Final (Immuno Chapter 7 thru end of packet) Flashcards
B cells begin their lives in the BM. The initial __________________ differentiation step in BM ultimately leads to the mature naive B cells. Mature B cells migrate to secondary lymphatic organs/tissues such as spleen and lymph nodes and begin __________________ stages of B cell differentiation to plasma cells or memory B cells
antigen-independent, antigen-dependent
After B cells are activated by an antigen and helper T cells, the antibody is secreted by plasma cells. The Ab has 3 main functions in humoral immunity. What are they?
1) neutralization
2) opsonization
3) complement activation
Which Ab is always secreted first?
IgM
What is the major function of plasma cells?
secrete Abs
Which Abs can do neutralization? How do they do neutralization?
IgM, IgG, and IgA can neutralize the epitope by surrounding it and preventing the bacteria from multiplying
Which Ab is an opsonin? How does this work?
IgG coats the epitope to make it yummy for macrophages to eat it
Which complement protein is used in opsonization?
C3b
During the process of _____________, antigens are bound by Ab and/or complement molecules. Phagocytic cells express receptors that bind opsonin molecules; With the antigen coated with these opsonin molecules, binding of the antigen to the phagocyte is greatly enhanced.
opsonization
Some B-cells, do not differentiate into plasma cells, but remain as long-lived “___________”. Upon subsequent encounter with the same Ag, these memory cells undergo the immune memory phenomenon.
memory cells
_____________, also known as anamnestic response, is the rapid response with more Ab production with a booster shot or in a natural reencounter of antigen. Lymphocytes remember the past stimulation. After they encounter the same Ag again, B lymphocytes immediately go into action without much delay.
Immune memory
T/F: a vaccine is an antigen
true
What is class switching?
first Ab is always IgM
but then can switch to IgG, IgA, or IgE as needed
What is the difference between primary and secondary immune response with an antigen?
Cell Mediated Immunity is especially important for destroying intracellular bacteria, viral infections
and tumor cells. The effector cells involved in the Cell Mediated Immunity are….
-cytotoxic T lymphocytes (CTLs)
-NK-cells
-K-cells (killer cell, type of NK cell)
Cytotoxic T lymphocytes (CTLs), like other T-cells are both antigen and MHC-restricted. CTLs require:
recognition of a specific endogenous antigenic determinant; and recognition of “self” MHC. CTLs
recognize antigen via their T-cell receptor. This receptor makes specific contacts with the antigenic determinant and the target cell’s class ____ MHC molecule. CTLs also express CD____, which may assist the antigen recognition process.
1, 8
A host cell infected with a virus or cancer cell display the antigens on its surface complexed with a Class I MHC molecule. When recognition takes place, the CD8 co-receptor on the CD8 T cell binds to the MHC I on the Nucleated Cell. When activated CTLs recognize antigen fragments, the T cells begin to secrete toxins (______________________________) that cause lysis or apoptosis of the infected cell
perforin, granzymes, and granulysin
NK cells are part of a group know as the “large granular lymphocytes”. These cells are generally non-specific (Innate Immunity), MHC unrestricted cells involved primarily in the elimination of….
neoplastic or tumor cells
NK-cells contain immunoglobulin Fc receptors on their surface and are involved in ______________________ (ADCC). ADCC occurs as a consequence of antibody being bound to a target cell surface via specific antigenic determinants expressed by the target cell. Once bound, the Fc portion of the immunoglobulin can be recognized by the K-cell. Killing then ensues by a mechanism similar to that employed by CTLs.
Antibody-dependent Cell-mediated Cytotoxicity
Antibody-dependent Cell-mediated Cytotoxicity (ADCC) can result in type ____ hypersensitivities, for example, rheumatic fever from S. pyogenes
2
The complement system found in the blood of mammals is composed of 26 heat labile substances
(proteins) that combine with antibodies on cell surfaces. Most of the complement components are
numbered (e.g. C1, C2, C3, etc.) but some are simply referred to as “Factors”. The complement
system must be activated in order to function, which can be activated via three distinct pathways. All
of which lead to the production of C3 (the end of the early stage). What are the 3 pathways?
1) classical pathway
2) lectin pathway
3) alternative pathway
Are complement proteins always active?
no they circulate in the blood inactively until they’re needed
What cells produce complement proteins?
liver cells
Which complement protein pathway starts with an Ag-Ab complex/immune complex that binds together to make C1 and activates C2 + C4 to make C3 convertase?
classical pathway
Which complement protein pathway has a microbial mannose (sugar) interact with MBL (lectin) to make C3 convertase?
lectin pathway
Which complement protein pathway uses factor b and factor d to make C3 convertase?
alternative pathway
What 2 complement proteins make up C3 convertase in the classical pathway?
C2b and C4b
What is the function of C3b?
opsonization and phagocytosis
What is the function of C3a?
inflammation
What is the function of C5a?
inflammation
What complement proteins make up the MAC which leads to lysis of a microbe?
C5, C6, C7, C8, and multiple/polymerized C9
What are the 4 functions of the complement cascade/common pathway (this is once all 3 complement protein pathways make C3 convertase and now are the same pathway)?
***I’m assuming this will be a test question because he repeated it several times
1) opsonization by C3b makes bacteria more susceptible to phagocytosis
2) clearance of immune complex (immune complexes are small and help attach to RBCs to assist in clearance)
3) inflammation produces chemostactic substances like C3a and C5a to increase vascular permeability, cause smooth muscle contraction, and produce mast cell degranulation
4) MAC is made when C5b initiates the late stage of complement cascade and results in the production of C5b, C6, C7, C8, and polymerized C9, which forms MAC! It is called MAC bc it creates holes in cell membranes of target cells, directly lysing some bacteria and foreign cells
note: *During the process of opsonization, antigens are bound by antibody (i.e. Ig G) and/or complement (C3b) molecules. Phagocytic cells express receptors that bind opsonin molecules. These include the Fc receptors. With the antigen coated in these molecules, binding of the antigen to the phagocyte is greatly enhanced. Most phagocytic binding cannot occur without opsonization of the antigen.
Which 2 complement proteins are produced as an inflammatory response and increases vascular permeability, causes smooth muscle contraction, and promotes mast cell degranulation?
C3a and C5a
C5b initiates the late stage of the complement cascade, resulting in the production of C5b, C6, C7, C8, and polymerized C9, which forms the MAC. Where does MAC get its name from? aka what does MAC do?
MAC creates holes in cell membranes of target cells, directly lysing some bacteria and foreign cells
What portion of the Ab binds to complement and the antigen in the classical pathway?
Fc portion, and once it binds then it is known as the C1 complex which starts the whole pathway
T/F: immunization can also be called vaccination
FALSE
vaccines are a part of immunization, so vaccines can be said as immunization but not the other way around
What are vaccines made of (generally)?
-killed or attenuated bacteria, virus, or attenuated toxin known as toxoids
-a toxoid is a bacterial toxin whose toxicity has been inactivated by chemicals or heat while the immunogenicity is maintained
What are booster injections?
-additional inoculations introduced to increase immune response- make response faster and stronger
-causes anamnestic (memory) response
What are the 4 categories under immunizations?
1) vaccine
2) booster injections
3) attenuated
4) titer
What does attenuated mean?
-rendered incapable of causing disease (mutated), but is capable of inducing immunity and is still a live organism
-reduced toxicity, is not as lethal
What does titer mean?
-concentration, may be used for describing conc. of Ab or virus
-an Ab titer is a measurement of how much antibody and organism has been produced that recognizes a particular epitope
What is an adjuvant?
-substance that can enhance the immune response to an immunogen, such as a vaccine, while having few if any direct effects when given by itself
-adjuvants may have side effects like fever and inflammation
-adjuvants do not increase immune response, but rather increase immunogenicity
What are the 4 different types/modes of acquiring immunity?
1) natural active immunity
2) artificial active immunity
3) natural passive immunity
4) artificial passive immunity
Which type of immunity is where the host makes their own antibodies?
active immunity
Which type of immunity is where the host receives Abs made by others or from an animal serum?
passive immunity
Which immunity type is where the Ab formation is stimulated by the presence of an antigen such as living organisms or their products which causes disease?
natural active immunity
Which immunity type is this an example of?
-you caught the flu while walking through a sneeze from a fellow student
-this is accidental, you’re just living everyday life
-your body makes the Ab for this flu
natural active immunity (body is actively working to gain immunity)
Which immunity type will recover from a flu or smallpox?
natural active immunity
Which immunity type will have life-long immunity?
natural active immunity (like with measles, mumps, and smallpox)
Which immunity type is where the Ag is composed of an attenuated (living but reduced toxicity) microorganism or detoxified products like a toxoid and is administered to the host which stimulates Ab production?
artificial active immunity
Which immunity type has intentional exposure?
artificial active immunity
Which immunity type is all vaccines?
artificial active immunity
Which immunuty type is a flu shot?
artificial active immunity
Which immunity type has solid protection for many years and is long lasting especially after a booster shot?
artificial active immunity
Which immunity type is where the Ab acquired in utero is while the baby is in the womb?
natural passive immunity
Which immunity type is where the Ab conferred while the baby is nursing is in the mother’s breast milk?
natural passive immunity
Which immunity type makes Abs when fetus is in the uterus, or baby is getting breast milk?
natural passive immunity
Which immunity type would IgG transplacental fall under?
natural passive immunity
Is natural passive immunity short term or long term immunity?
short term (weeks to months)
Which immunity type is conferred by injection of serum containing Abs from an immune animal or human being to a susceptible individual?
artificial passive immunity
Which immunity type is uses Ab serums to provide immediate but temporary protection?
artificial passive immunity
An antitoxin of tetanus or diphtheria is an example of which type of immunity?
artificial passive immunity
Which immunity type has the Ab formation stimulated artificially and the protection only lasts a few weeks (short-term)?
artificial passive immunity
What are the 5 main types of vaccines?
1) live attenuated vaccines (ex: MMR, rotavirus, smallpox, chickenpox, yellow fever, etc.)
2) inactivated vaccines (ex: Hep A, flu shot, polio shot, rabies vaccine, etc.)
3) subunit, recombinant, polysaccharide, and conjugate vaccines
4) toxoid vaccines
5) DNA vaccines
Hypersensitivities refers to undesirable overreactions produced by the normal immune system to certain allergens. Allergens are antigens that causes the allergic reaction, e.g. pollen, mites, bee stings, dust…etc. Hypersensitivity reactions require a ________________________ of the host, i.e. have a first exposure to the allergen.
pre-sensitized (immune) state
How many types of hypersensitive are there?
5 types
Type 1 hypersensitivity reaction is also known as….
IgE mediated reaction or anaphylactic reaction
Which hypersensitivity reaction is commonly referred to as an allergy?
type 1 hypersensitivity/ IgE mediated
Type 1 hypersensitivity/ IgE mediated reaction usually occurs in individuals who have formed allergen specific IgE Abs following exposure and sensitization to specific allergens. Allergens are normally proteins derived from food, drugs, house-dust mites, animal dander, grass, and tree pollen. This reaction involves what cells?
mast cells and basophils
Type 1 hypersensitivity/ IgE mediated reaction usually occurs in individuals who have formed allergen specific IgE Abs following exposure and sensitization to specific allergens. Allergens are normally proteins derived from food, drugs, house-dust mites, animal dander, grass, and tree pollen. This reaction involves mast cells and basophils. What are the mast cell mediators that are released through degranulation following the activation of cell surface receptors on mast cells?
1) histamine
2) thromboxane
3) prostaglandin
4) leukotriene
5) platelet activating factor
There are 5 mast cell mediators in IgE mediated hypersensitivity/type 1 hypersensitivity. The 5 mediators are:
1) histamine
2) thromboxane
3) prostaglandin
4) leukotriene
5) platelet activating factor
What effects do these mediators have?
1) vasodilation and increased permeability
2) airway smooth muscle spasm
3) leukocyte extravasation
Generally, anything that has “allergy” in the name is considered a…..
type 1 hypersensitivity/ IgE hypersensitivity
What are some examples of type 1 hypersensitivity/ IgE hypersensitivity reaction?
-allergic asthma
-allergic conjunctivitis
-allergic rhinitis (hay fever)
-urticaria (hives)
-atopic dermatitis
What is the worst case scenario of type 1 hypersensitivity/IgE mediated reactions? What are the most common causes of this?
systemic anaphylaxis
-severe histamine and other chemicals release occurs resulting in smooth muscle contraction, especially of the bronchioles causing life threatening respiratory distress, usually followed by vascular collapse and shock
-most commonly caused by penicillin injection, bee stings, latex allergy, food allergy
-adrenaline/epi is injected immediately at the first sign of anaphylaxis (has the opposite effects of histamine and other other mast cell mediators)
What is desensitization?
-allergy shots
-they help turn down the immune response to the allergen
-this results in less production of IgE Ab to this antigen
-this also helps produce “good” Ab IgG to neutralize the antigen
-basically the shot helps you to class switch Abs to train your body
Which antibodies are involved in type 2 hypersensitivity?
IgG and IgM, known as dependent cytotoxicity
Which hypersensitivity reaction is this?
-dependent cytotoxicity
-complement dependent
-Ab is directed against Ag on cells such as RBCs or extracellular membranes like the basement membrane
-the resulting Ag Ab complex activates complement via the classical pathway and leads to cell lysis or extracellular tissue damage
type 2
If a hypersensitivity reaction is receptor mediated then it is a….
type 5 hypersensitivity
What are some examples of type 2 hypersensitivity reactions?
-autoimmune anemia
-idiopathic thrombocytopenia purpura
-erythroblastosis fetalis (hemolytic disease of the newborn)
-acute hemolytic transfusion reactions
-pernicious anemia
-rheumatic fever from S. pyogenes (IgG/IgM affects the heart)
-goodpasture’s syndrome
-bullous pemphigoid
-pemphigus vulgar
-Grave’s disease and MG (these are type 5 hypersensitivity)
What Abs are involved in type 3 hypersensitivity?
IgG or IgM
Which hypersensitivity reaction is also known as immune complex hypersensitivity?
type 3
Which hypersensitivity reaction is this?
-occurs when there is an accumulation of immune complexes that have not been adequately cleared giving rise to an inflammatory response and attraction of leukocytes
-this can lead to immune complex diseases
type 3 hypersensitivity
What are some examples of type 3 hypersensitivity reactions?
-serum sickness
-arthus reaction (swelling and inflammation following tetanus vax)
-lupus
-polyarteritis nodosa
-poststreptococcal glomerulnephritis from S. pyogenes
-RA
note: there is also hypersensitivity pneumonitis but that is a mixed type hypersensitivity reaction with type 3 and 4
Which hypersensitivity reaction is also known as cytotoxic T cell CD8 mediated DELAYED reaction or delayed type?
type 4
Which hypersensitivity is this?
-takes 2-3 days to develop
-not Ab mediated, it is CELL mediated
-cytotoxic T cells cause direct damage whereas helper T cells secrete cytokines which activate cytotoxic T cells and recruit and activate monocytes and macrophages, which cause the bulk of the damage
type 4
What are some examples of type 4 hypersensitivity?
-MS
-guillain barre syndrome
-graft vs. host disease
-PPD and mantoux skin tests for TB caused by M. tuberculosis
-contact dermatitis (poison oak or ivy, nickel allergy, metal allergy like in jewelry)
Which Abs are involved in type 5 hypersensitivity?
IgG or IgM
Which hypersensitivity is an autoimmune disease and is receptor mediated?
type 5
What is the rarest hypersensitivity?
type 5 (its a special type of type 2)
What are the 2 examples of type 5 hypersensitivity?
graves disease and MG
What is an autograft?
tissue moved from one location to another in the same individual
What is an isograft or isogenic graft?
transplant from identical twins
What is an allograft or homograft?
transplant from genetically different members of the same species
What is a xenograft or heterograft?
graft from different species (does not last very long)
example: use an animal and transplant something into a human, like a pig valve for heart
T/F: if the graft is not auto or isogenic then it will be rejected
true
Graft rejection is a highly destructive phenomenon that can severely limit the success of organ and tissue transplantation. Graft rejection is a normal immune response against foreign MHC proteins on the surface of graft cells. Once graft rejection has begun, it can be classified in one of three ways in humans. These categorizations are based on how quickly rejection occurs. What are the 3 types?
1) hyperacute
2) acute
3) chronic
What is hyperacute graft rejection?
happens in minutes to hours because of performed anti-donor Ab and complement (humoral immunity causes it, Abs start circulating in the blood very fast)
What is acute graft rejection?
-takes days-weeks
-happens from primary activation of T cells (cell mediated immunity causes it)
What is chronic graft rejection?
-takes months-years
-cause is not clear
-may be Ab and cell mediated immunity
What is more common- graft rejecting host or host rejecting graft?
host rejecting graft
In Graft-versus-Host Disease, donor bone marrow T cells may regard the patient’s cells as foreign
and mount an immune response against them. Especially in __________ and ______ (organs rich
in lymphocytes) transplantation. Symptoms include rash, jaundice, diarrhea, GI hemorrhage.
bone marrow, liver
Tregs are involved in ______________ the immune response
turning down
Like helper T-cells, suppressor T-cells are stimulated by antigen but instead of releasing lymphokines that activate B-cells (and other cells), suppressor T-cells release factors that __________ the B-cell response.
suppress
too little helper T cells=
immunodeficiency
too much T reg cells= increased T8 cells=
immunodeficiency
too much T helper cells=
autoimmunity
too little T reg cells=
autoimmunity
