chapter 13 (module 4) Flashcards by Meagan Strickland

the adaptive immunity is the product of a dual system, the

T and B lymphocytes

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the ability of the body to react with countless foreign substances

immunocompetence

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molecules that can be seen and identified by the immune system

antigens

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Antigens may or may not provoke an immune response after being sensed by the immune system, if they do provoke a response they can be called ________.

immunogens

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these molecules are usually protein or polysaccharide molecules on or inside all cells or viruses

antigens

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the precise molecular group of an antigen that defines its specificity and triggers the immune response

-> primary signal that a molecule is foreign

epitope

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adaptive immunity

specificity***

response is focused on a single specific antigen

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adaptive immunity

diversity

there is always at least one cell that can react against any antigem

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adaptive immunity

inductibility

only turned on when triggered

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adaptive immunity

tolerance

does not react with self antigens

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adaptive immunity

clonality

generates millions of cells with same specificity

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adaptive immunity

memory***

rapid mobilization of lymphocytes preprogrammed to recall their first engagement with the antigen

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the elegance and complexity of immune function are largely due to _______ working closely with ________

lymphocytes and phagocytes

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adaptive immune response

stage one: lymphocyte development and clonal deletion

arise from the same stem cell type but diverge into T (thymus) and B cells (specialized bone marrow sites)
T and B cells constantly migrate in and out of lymphoid organs

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adaptive immunity

stage two: entrance and presentation of antigens and clonal selection

foreign cells enters tissues
tissue macros ingest it and may induce inflamm response
tissue dendritic cells ingest the antigen and migrate it to the nearest lymphoid organ (often the lymph nodes)
the lymphoid organs process the antigen and present it to T and B lymphocytes
B cells may need help from Helper T cells to initiate response

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role of markers

each have a distinct and significant role in detection, recognition, and cell communication

-serve to activate different components of immunity

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a set of genes in mammals that produces molecules on surfaces of cells that differentiate among different individuals in the species

major histocompatibility complex (MHC)

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this genes complex gives rise to a series of glycoproteins found on all cells except RBCs

also called the human leukocyte antigen (HLA)

MHC genes

major histocompatibility complex

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three classes of MHC genes

Class I genes code for markers that appear on all nucleated cells
Class II MHC genes code for immune regulatory markers (found on macrophages, dendritic cells, and B cells, T cells)
Class II MHC genes encode proteins involved with the complement system, among others.

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CD molecules

cluster of differentiation, naming scheme for many of the cell surface molecules (well over 400 have been names)

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lymphocyte markers

frequently called receptors because it emphasizes there major role in accepting or grasping antigens in some form

-B cells have receptors that bind antigens and T cells have receptors that bind antigens that have been processed and complexed with MHC molecules on their presenting cell surface

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adaptive immunity

stage three: challenging B and T cells with antigens

when challenged by an antigen B and T cells proliferate and differentiate
the multiplication of a particular lymphocyte creates a clone, or group of genetically identical cells, some of which are memory cells that will ensure future reactiveness against that antigen

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adaptive immunity

stage 3a: How T cells respond to antigen

-T cell types and responses are extremely varied

when activated by an antigen, a T cell gives rise to a variety of different cells with different roles:
1. Helper T cells that activate macrophages, assist B cells, and help activate cytotoxic T cells
2. Regulatory T cells that control T-cell response by secreting anti-inflammatory cytokines or preventing proliferation
3. Cytotoxic T cells that lead to the destruction of infected host cells and other foreign cells

*T cells do not produce antibodies

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adaptive immunity

Stage 3b: How B Cells Respond to Antigen: Release of Antibodies

when a B cell is activated or sensitized by an antigen, it DIVIDES, giving rise to plasma cells, each with the same reactive profile

plasma cells release antibodies into the tissue and blood
when these antibodies attach to the antigen for which they are specific, the antigen is marked for destruction or neutralization

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13.2

Stage I: The development of Lymphocyte Diversity

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t cells reach maturity in the thymus, and also the ___________

GI tract

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In addition to the antigen-specific T cell receptor, all mature T lymphocytes express coreceptors called ___, which surround the T-cell receptor and assist in binding.

CD3

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T cells express CD3, ___, or a ___ coreceptor.

CD4, CD8

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___ is an accessory receptor protein mostly found on T Helper cells that helps the T cell receptor bind to MHC class II molecules

CD4

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___ is mostly found on cytotoxic T cells, and it helps bind MHC class II molecules

CD8

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Contrasting Properties of B and T Cells

Site of Maturation:
T- thymus
B- bone marrow

Specific Surface Markers:
T-T-cell receptor, several CD molecule
B- immunoglobulin

Circulation in Blood
T- high numbers
B- low numbers

Receptors for Antigens
T- T-cell receptor
B- B cell receptor (immunoglobulins)

Distribution in Lymphatic Organs
T- paracortical sites (interior to the follicles)
B- cortex (in follicles)

Require Antigen Presented with MHC
T- Yes
B- No

Product of Antigen Stimulation
T- several types of activated T cells and memory cells
B- plasma cells with memory cells

General Functions
T- cells activated to help other immune cells, suppress/kill abnormal cells, mediate hypersensitivity, synthesize cytokines
B- production of antibodies to inactivate, neutralize, target antigens

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DiGeorge Syndrome

thymus deficiency

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Severe Combined Immunodeficiency Syndromes (SCID)

group of genetic disorders resulting from defective hematopoietic precursor cells, causing a deficiency of both B and T lymphocytes

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Cancer (thymomas and thymic lymphomas)

tumors that originate from thymic epithelial cells (thymomas)
tumors originating from thymocytes (thymic lymphomas)

primary tumors affecting the thymus

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B cells develop in the bone marrow, and as a result of gene __________ and __________, hundreds of millions of distinct B cells develop

modification and selection

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it is estimated that each human produces antibodies with ___ trillion different specificities.

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large glycoprotein molecules that serve as the antigen receptors of B cells, and when secreted, as antibodies

-> the specific B-Cell receptor

immunoglobulins

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specific regions at the ends of the antibody “Y” molecule that recognize specific antigens; highly variable in shape so they can fit a wide variety of antigens

antigen binding site

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variable (V) region

the antigen-binding fragment of an immunoglobulin molecule, consisting of a combination of heavy and light chains whose molecular conformation is specific for the antigen

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what process is responsible for the increase in numbers of lymphocytes?

clonal expansion after antigen encounter causes B cells and T cells to proliferate

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receptor similarities and differences between B and T cells

T is similar to B in that

its receptor is formed from genetic modification
it has variable and constant regions
it is inserted into the membrane
it has an antigen binding site formed from parallel polypeptide chains

however, unlike the B cell receptor, T-cell receptor is relatively small and is NEVER secreted

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a conceptual explanation for the development of lymphocyte specificity and variety during immune maturation

clonal selection

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after activation, the B or T cell multiplies rapidly in a process called _______ _______

clonal expansion

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what are the two important features of clonal selection?

Lymphocyte specificity is preprogrammed, existing in the genetic makeup before an antigen has ever entered the tissues
Each genetically distinct lymphocyte expresses only a single specificity and can react to that chemical epitope

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the lymphocytes that develop a specificity for self molecules are eliminated in a process called _______ _______, and leads to ________ _________.

clonal deletion

immune tolerance

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mitotic division of a specific lymphocyte expand into a larger population of lymphocytes all bearing the same specificity, with the goal to fight the specific epitope they recognized

clonal expansion

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13.3 Stage II: Presentation of Antigens

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an antigen must be perceived as ________

foreign

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materials that serve as good immunogens

proteins and polypeptides (enzymes, cell surface structures, exotoxins)

lipoproteins (cell membranes)

glycoproteins (blood cell markers)

nucleoproteins (DNA complexed to proteins but not pure DNA)

polysaccharides (certain bacterial capsules) and lipopolysaccharides

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characteristics of “good” immunogens (provoking a strong response)

a. their chemical composition
b. their context–meaning what type of cytokines are present
c. their size

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we can generalize that ____ antigens are better than ____ antigens. however a large size alone is not sufficient for immunogenicity

large

2. small

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poor immunogens

trisaccharide
polypeptide

->small molecules and linear molecules are less likely to be good immunogens

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an incomplete or partial antigen, cannot stimulate a full immune response

hepten

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True or False
A hapten can link to a larger carrier molecule and the two combined can develop immunogenicity; the hepten serves as the epitope

true

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List some examples of haptens

drugs, metals, and ordinarily innocuous household, industrial, and environmental chemicals

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many haptens __________ develop antigenicity in the body by combining with larger molecules such as serum proteins

inappropriately

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cell surface molecules and markers that occur in some members of the same species but not others

-> are the basis for an individual’s blood group and major histocompatibility profile = responsible for incompatibilities that can occur in blood transfusion or organ grafting

Alloantigens

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bacterial toxins that are potent stimuli for T cells and can be a factor in diseases such as toxic shock

->their presence can activate T cells at a rate 100 times greater than ordinary antigens = the result can be an overwhelming release of cytokines and cell death

superantigens

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antigens that evoke allergic reactions

allergens

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cells that grab the antigen-carrying microbe and ingest it, degrade it, and pass it’s antigens back out onto their membranes complexed with MHC-I or MHC-II markers, and then presented to T lymphocytes

antigen-presenting cells (APCs)

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what three cells are APCs?

B cells, macrophages, and dendritic cells

-> dendritic being the most potent

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most antigens must first be presented to T cells, even though they will eventually activate T and B cell systems.

However, a few antigens can trigger a response directly from B lymphocytes without APCs or T helper cells, what are these called?

T-cell-independent antigens

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usually simple molecules such as carbs with many repeating and invariable determinant groups

ie. lipopolysaccharide from the cell wall of E. coli or polysaccharide from the capsule of Streptococcus pneumoniae, and molecules from rabies and Epstein-Barr virus

T-cell-independent antigens

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list characteristics of antigens that optimize their immunogenicity

Chemical composition
Size
what types of cytokines are present

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list the types of cells that can act as antigen presenting cells

Dendritic cells
Macrophages
B cells

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describe how the immune system responds to alloantigens and superantigens

superantigens: activates an on overwhelming response from T cells causing cell death and too much release of cytokines ie. toxic shock
alloantigens: can cause incompatibilities during organ grafting and blood transfusions, can cause self-attack

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13.4 Stages III and IV: T-Cell Response

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why are T cells referred to as “restricted”

they require some type of MHC (self) recognition before they can be activated

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what is the result of T cell stimulation?

mobilization of other T cells, B cells, and phagocytes

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Memory T cells are some of the ______-_____ blood cells known

longest-lived

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T Helper Cell 1

Co-receptor(s): CD4

Function:

activates the cell-mediated immunity pathway
secretes tumor necrosis factor and interferon gamma
responsible for delayed hypersensitivity (allergy occurring several hours or days after contact)
secretes IL-2

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T Helper Cell 2

Co-receptor(s): CD4

Function:

can activate macrophages to expel helminths or protozoans, phagocytose extracellular antigens
contributes to type 1 (allergic) hypersensitivity
can encourage tumor development

T Helper Cell 17

Co-receptor(s): CD4

Function:
-promotes inflammation

T Follicular Helper Cell

Co-receptor(s): CD4, CD40L

Function:

drives B-cell proliferation
aids B cells in antibody switching class

T Regulatory Cell

Co-receptor(s): CD4, CD25

Function:

controls adaptive immunity response
prevents autoimmunity
can contribute to cancer progression

T Cytotoxic Cell

Co-receptor(s): CD8

Function:

destroys a target foreign cell by lysis
important in destruction of complex microbes, cancer cells, virus-infected cells
graft rejection
requires MHC-I for function

Gamma-delta T cells

Function:

react in the innate and adaptive systems
responsive to lipid antigens

general overview of Helper T cells

they all bear the CD4 marker
critical in regulating immune reactions to antigens (B and T cells)
activate macrophages both directly (receptor contact) and indirectly (by releasing cytokines like interferon gamma)
some T helper cells secrete IL-2 and some secrete IL-4, 5, 6

**most prevalent type of T cell in the blood and lymphoid organs, making up about 65% of the T cell population

->the severe depression of T helper cells by HIV is what largely accounts for the pathology of AIDS

proteins released by cytotoxic T cells that produce pores in target cells

perforin

enzymes secreted by cytotoxic T cells that damage proteins of target cells

granzymes

a T lymphocyte programmed to directly affix cells and kill them

-for this cell to be activated it must recognize a foreign peptide complexed with self MHC-I and mount a direct attack upon the target cell; involves the secretion of perforins (punch holes in target cell membranes) and granzymes (enter said pores and attack proteins)

Killer T cells

cytotoxic T cells have one job: to destroy other cells such as what

virally infected cells - recognize telltale virus peptides expressed on virus surface (also target cells carrying intracellular bacteria)

cancer cells - attack any abnormal cells they encounter in the tissues (this fx is clearly seen in the susceptibility of T-cell-deficient people to cancer)

cells from other animals and humans - most important factor in graft rejection (attack foreign tissues that have been implanted into a recipient’s body)

what two types of T cells are always present in any given immune response?

T Helper cells and T Cytotoxic cells

T cells that are considered a bridge between the innate and adaptive immune responses due to the fact that they respond to certain kinds of PAMPs on microorganisms the way WBCs in the innate system do

-> particularly responsive to certain types of phospholipids and can recognize and react against tumor cells

Gamma-delta T Cells

type of lymphocyte related to T cells that lack specificity for antigens; they circulate the spleen, blood, and lungs, and are probably the first killer cells to attack cancer cells and virus-infected cells

-> destroy cells by similar mechanisms as T cells, but are not considered a part of the adaptive system

Natural Killer (NK) cells

hybrid kind of cells that is part killer cell and part T Cell, with T cell receptors for antigen and the ability to release large amounts of cytokine very quickly -> leading to cell death

= are considered to be a another important link between innate and adaptive immunity

Natural Killer T Cells (NKT Cells)

T cell system overview

T cells differentiate into five different types of cells (and also memory cells), each of which contributes to the orchestrated immune response, under the influence of a multitude of cytokines

13.4 Outcome

describe the main differences between T helper cells and C cytotoxic cells

The key difference between T helper cells and cytotoxic cells is that helper T cells are involved in coordination of the immune response against the pathogen with B cells and other T cells…..
while cytotoxic cells directly kill or destroy cancer cells and infected cells.

note the similarities and differences between gamma-delta T cells an other T cells

gamma-delts t cells are much faster because they respond to certain kinds of PAMPs
they both have t cell receptors, memory cells

13.5 Stages III and IV: B-Cell Response

the two arms that bind antigen are termed what

antigen binding fragments (Fabs)

composite of four polypeptide chains, a pair of identical heavy (H) chains and a pair of identical light (L) chains, and the two heavy chains are bonded to one another with disulfide bonds

“Y” shaped arrangement

immunoglobulin

what is at the end of each Fab fragment?

epitope

T or F

Fab fragments can change their angle to accommodate nearby antigen sites that vary slightly in distance and position

TRUE

the site on the antibody where the epitope binds is composed of a ________________, whose amino acid content can be extremely VARIED

hypervariable region

principal activity of an antibody

to immobilize, call attention to, or neutralize the antigen for which it was formed

= job of antibody is to ruin antigen

a process that makes microbes more readily recognized by phagocytes so that they can dispose of them

opsonization

performed by antibodies called opsonins

in _______ reactions, antibodies fill the surface receptors on a virus or the active site on a microbial enzyme to prevent it from attaching normally

neutralization

an ________ is a special type of antibody that neutralizes bacterial exotoxins

antitoxin

________ is the result of antibodies cross-linking cells or particles into large clumps, and rendering the microbes immobile and enhances phagocytosis

agglutination of antigens

the interaction of an antibody with complement can result in what?

the specific rupturing of cells and some viruses

the portion of the antibody below the Fabs

crystallized fragment the bottom portion of the “Y”

structural and functional classes of immunoglobulins

isotypes

The Fc end of an antigen can bind to receptors on the membranes of cells, such as macrophages, neutrophils, eosinophils, mast cells, basophils, and lymphocytes.

-> the effect of an antibody’s Fc end binding to a cells depends on _______

that cell’s role

The Fc end of the antibody of allergy (IgE) binds to basophils and mast cells, which causes the release of allergic mediators such as _____

histamine

IgG

Monomer
2 binding sites
% of total antibody in serum: 80%
average half life in serum (days): 23
crosses placenta
Fc binds to phagocytes
most prevalent antibody

-produced in primary response, neutralizes toxins, opsonizes, fixes complement

IgA

number of antigen binding sites: 4,2
% of total antibody in serum: 13%
average half life in days: 6
the dimer, secretory IgA, is formed by two monomers held together by a J chain
dimer is secretory antibody on mucous membranes
monomer is in small quantities in blood
high amount of IgA in colostrum
provides the most important adaptive local immunity to enteric, resp, and genitourinary pathogens

IgM

10 antigen binding sites
% of total antibody in serum: 6%
average half life in serum in days: 5
fixes complement

-produced at first response to antigen, it can serve as a B-cell receptor

complement-fixing antibody

antibody that combines with antigen leading to the binding and activation of complement, which may result in opsonization or cell lysis

IgD

2 antigen binding sites
% of total antibody in serum: 1%
average half life in serum in days: 3
pentamer

-is the receptor on B-cells and a triggering molecule for B cell activation

IgE

2 antigen binding sites
% of total antibody in serum: 0.002%
average half life in serum in days: 2.5
Fc binds to mast cells and basophils
antibody of allergy and of worm infections
it also mediates anaphylaxis, asthma, etc.

a blood protein produced in response to and counteracting a specific antigen

antibody

concentration of antibodies; determined by agglutination methods

titer

the first response of the immune system when exposed to an antigen

primary response

the rapid rise in antibody titer following a repeat exposure to an antigen that has been recognized from a previous exposure; this response is brought on by memory cells produced as a result of the primary exposure

secondary response

another name for secondary response; an augmented response or memory r/t a prior stimulation of the immune system by antigen, it boosts the level of immune substances

anamnestic response

latent phase of primary response

lack of antibodies for antigen, but the antigen is being processed by the correct clones of B lymphocytes

what antibody is most prevalent early in the primary response?

IgM (first class to be secreted by the plasma cells)

later in the primary phase, IgM changes over to mostly what antibody?

IgG or some other class (IgA or IgE)

-> remember, IgG is produced in a primary response and by memory cells (table 13.8)

what is now known about memory cells r/t the previous thought that memory B and T cells are only created from clones activated by a specific antigen?

it seems that exposure to a particular antigen can result in memory cells that will recognize antigens that are chemically related to it, even if those antigens have not been seen by the host

> this makes sense: adaptive immunity occurs via recognition of epitopes, so if other microbes share those same chemical signatures (epitopes), memory cells will react against them as well
ie. in Africa, vaccinating against measles also cuts death rates from pneumonia, sepsis, and diarrhea by one third

B cell activation

antigen binds to reg. B cell
antigen is endocytosed by the B cell and degraded into smaller peptide determinants -> the antigen is then bound to the MHC-II receptors on the surface of B cell
most B cell must interact with already activated T Helper cell, they engage in linked recognition
the combination of these stimuli on the membrane receptors causes a signal to be transmitted internally to the B cell nucleus -> B cell activation
differentiation -> regulatory cells, plasma cells, and memory B cells are produced
clonal expansion -> each type of cell expands its population by mitosis (memory cells seed the lymphatic circulation, reg cells proliferate and secrete IL-10 to regulate T cell response, plasma cells)

only antibody that crosses the placental barrier, and Fc binds to phagocytes; most prevalent antibody

IgG

IgG, IgE, IgM, IgA, IgD

isotypes of antibodies

immunity can be natural or __________, and it can be either active or _______.

artificial

passive

any immunity that is acquired during the normal biological experiences of an individual rather than through medical intervention

natural immunity

protection from infection obtained through medical procedures; induced by immunization with vaccines and immune serums

artificial immunity

occurs when an individual receives an immune stimulus (antigen) that activates the B and T cells, causing the body to produce immune substances such as antibodies

active immunity

characteristics of active immunity

creates a memory that renders the person ready for quick action upon re-exposure to the same antigen
it requires several days to develop
it lasts for a relatively long time, sometimes for life
* can be stimulated by natural or artificial means

occurs when an individual receives immune substances (usually anti-bodies) that were produced actively in the body of another animal or human donor; recipient is protected for a short time, even though he or she has not had prior exposure to the antigen

passive immunity

characteristics of passive immunity

lack of memory for the original antigen
lack of production of new antibodies against the disease
immediate onset of production (individual receives immune substances immediately, ie. antibodies)
short-term effectiveness because antibodies have limited time period of function, and ultimately, the recipient’s body disposes of them

*can be natural or artificial in origin

immunity that is for a short period of time, but offers immediate immunity

passive

give an example of natural passive immunity

prenatal/postnatal mother-child relationship

> IgG antibodies circulating in the maternal bloodstream can pass through the placenta
> IgA in Mother’s milk, provide special type of intestinal immunity

example of natural active immunity

after recovering from an infectious disease like the seasonal flu, and building immunity for it

give an example of artificial active immunity

vaccination

give an example of artificial passive immunity

involves a preparation that contains a particular infectious agent;

pooled human serum from donor blood (gamma globulin)
immune serum globulins containing high quantities of of antibodies

convalescent serum and SARS-CoV-2

serum containing antibodies from people who were ill with SARS-CoV-2 and had recovered

-> this approach is useful when there is no vaccine yet available

a hazardous, outmoded process deliberately introducing smallpox material scraped from a victim into the nonimmune subject in hope of inducing resistance (10th century attempt at immunization)

variolation

term originally used in reference to inoculation with the cowpox or vaccinia virus to protect against small pox; in general the term now pertains to injection of whole microbes (killed or attenuated), toxoids, or parts of microbes as a prevention or cure for disease

vaccine

phase I of vaccine clinical trials

20-100 healthy volunteers

is this vaccine safe
does it seem to work
are there any serious side effects
how is the size of the dose related to side effects

phase II of clinical trials

several hundreds of volunteers

what are the common short-term side effects
how are the volunteer’s immune systems responding to the vaccine

phase III of clinical trials

hundreds or thousands of volunteers

how do people who get the vaccine and people who do not get the vaccine compare
is the vaccine safe
is the vaccine effective
what are the most common side effects

the FDA licenses a vaccine only if:

it’s safe and effective

- its benefits outweigh its risks

vaccines are made in batches called ____.

lots

what are the only two natural forms of passive immunity

through placenta

2. through breastmilk (IgA)

Intravenous immunoglobulin (IVIG)

sometimes called gamma globulin

-contains immunoglobulin extracted from the pooled blood of human donors

method of processing IVIG

concentrates the antibodies to increase potency and eliminates potential pathogens such as HIV and Hep B

What patients is IVIG most useful in?

patients who have a diminished ability to mount their own immune response, or if the disease is so fast acting that it could be fatal before the victim develops their own antibodies (tetanus, rabies)

specific immune globulin (SIG)

derived from a more defined group of donors; derived from patients who are convalescing and in a hyperimmune state after infections such as Hep B, pertussis, tetanus, chicken pox

why is SIG preferable over IVIG?

because SIG contains higher titers of specific antibodies obtained from a smaller pool of patients

basic principle behind vaccination

to stimulate a primary response and a memory response that primes the immune system for future exposure to a virulent pathogen

qualities of an ideal vaccine

it should protect against exposure to natural, wild forms of the pathogen
it should have a low level of adverse side effects or toxicity and not cause harm
it should stimulate both antibody (B-cell) response and cell-mediated (T-Cell) response
it should have long-term, lasting effects (produce memory)
it should not require numerous doses or boosters
it should be inexpensive, have a relatively long shelf life, and be easy to administer

vaccines can be broadly categorized as either whole-organism or

part-of-organism

subcategories of vaccine preparations

Whole cells or viruses
a. live, attenuated microbial cells or viruses
b. killed cells or inactivated cells
Part-of-organism preparations: antigen molecules derived from bacterial cells or viruses (subunits)
a. subunits derived from cultures of cells or viruses
b. subunits chemically synthesized to mimic natural molecules found on pathogens
c. subunits manufactured via genetic engineering
d. subunits conjugated with carrier proteins (often from other microbes) to make them more immunogenic -> these are called conjugated viruses

Whole Cell Vaccines

a. live, attenuated microbial cells or viruses

virulence is eliminated or reduced -> alive, with same antigenicity -> administer -> vaccine microbes can multiply and boost immune system

ie. measles, mumps, rubella, polio, contain live nonvirulent viruses

Whole Cell Vaccines

b. killed or inactivated virus

antigens -> heat or chemicals -> dead, but antigenicity is retained -> vaccine stimulates immunity but pathogen cannot multiply

ie. Hep A vaccine, three forms of the influenza vaccine contain inactivated viruses

because the microbes does not multiply inside the host, ______ vaccines often require a larger dose and more boosters to be effective

killed vaccines

attenuated meaning

lessened or eliminated

disadvantage of using live microbes in vaccines

they require special storage facilities and could conceivably mutate back to become virulent again

advantages of live preparation vaccines

viable microorganisms can multiply and produce infection (but not disease) like the natural organism
they confer long-lasting protection
they usually require fewer doses and boosters than other types of vaccines
they are particularly effective at cell-mediated immunity

subunit vaccines (parts of organisms)

if the exact epitopes that stimulate immunity are known, it is possible to produce a vaccine based on a selected component of a microorganism

> the antigens used in these vaccines may be taken from cultures of the microbes, produced by genetic engineering, or chemically synthesized
ie. examples of components used are the capsules of pneumococcus and meningococcus, the surface protein of anthrax, and the surface proteins of Hep B virus.

toxoid vaccine

a toxin that has been rendered nontoxic but is still capable of eliciting the formation of protective antitoxin antibodies; used in vaccines

> purified bacterial exotoxin that has been chemically denatured
ie. vaccines for diphtheria, tetanus, and pertussis

DNA vaccines

DNA from a pathogen is inserted into a plasmid vector and inoculated into a recipient with the expectation that the human cells will take up some of the plasmids and express the foreign DNA in the form of proteins

> b/c the proteins are foreign, they will be recognized during immune surveillance and cause B and T cells to be sensitized and form memory cells.
currently there are more than 500 DNA vaccines in trial

immunotherapy for cancer

T cells or dendritic cells are removed from the patient

> in a lab the cells are sensitized to known cancer antigens
> the now activated cells are injected back into the patients in the hopes that the actual tumor antigens match the ones used for activation in the lab and the patients own immune system will attack the tumor

this vaccine route can stimulate protection (IgA) on the mucous membrane of the portal of entry, and are also easier to give than injections and are more readily accepted

oral or nasal route administration

any compound that enhances immunogenicity and prolongs antigen retention at the injection site

-> precipitates the antigen and holds it in the tissues so that it will be released gradually

adjuvant

some vaccines require the addition of a special binding substance, or __________.

adjuvant

a chemical vehicle that enhances antigenicity, presumably by prolonging antigen retention at the injection site

adjuvant

more serious reactions in vaccines are extremely rare: fewer than 1 case in ______

220,000

thimerosal

phased out preservative used in vaccines that is thought to cause allergies and other potentially harmful side effects

some patients experience allergic reactions to the _____ used to grow the vaccine organism ie. eggs or tissue culture

medium

a phenomenon in which a certain amount of the population is vaccinated, preventing the microbes from circulating through the population

herd immunity

outcome 13.6

qualities of an ideal vaccine

protects against exposure to natural and wild forms of the pathogen
low level of adverse effects or toxicity and not cause harm
should stimulate antibody B cell response and cell-mediated T cell response
should not require numerous doses or boosters
should be inexpensive, long shelf-life, easy to admin
should have long-term lasting effects

outcome 13.6

four types of immunity

natural passive - placenta, breast milk (short term/immediate)
natural active - getting the seasonal flu and building immunity (long term)

artificial passive - immunotherapy (short term/immediate)
artificial active - vaccination (long term/in time)

outcome 13.6

name the two major categories of vaccines + their subcats

whole cell/virus vaccines

a. live, attenuated vaccines ie. measles
b. killed, inactivated ie. Hep A

subunit vaccines

a. derived from cultures of cells or viruses
b. subunits chemically synthesized to mimic natural molecules found on pathos
c. subunits manufactured via genetic eng
d. subunits conjugated with proteins to make them more immunogenic (conjugated vaccines)
ie. capsules of pneumococcus and meningococcus

a single bacterium has _______ epitope(s)

a. a single
b. multiple
c. MHC
d. clonal

b. multiple

the primary B cell receptor is

a. IgD
b. IgA
c. IgE
d. IgG

a. IgD

some microbial products can activate B cells without the assistance of T cells. Which of the following can do this?

a. Capsule of S. pneumoniae
b. lipopolysaccharide
c. some viral capsids
d. all of these

d. all of these

if you draw a blood sample from a patient to determine whether he or she has herpes simplex infection, and the patient displays a large amount of IgG against the virus but low levels of IgM, what do you conclude?

the patient has had the infection for a while

IgM

produced at first response to antigen

Brainscape's Knowledge GenomeTM

chapter 13 (module 4) Flashcards

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