Exam 4: Adaptive Immunity

Question 1

Antigen

Answer 1

A foreign substances that induces an immune response in the body

Question 2

Epitope

Answer 2

The part of an antigen that is recognized by a specific antibody

Question 3

Lymph

Answer 3

A fluid derived from the tissues of the body, resembling blood plasma and containing white blood cells, and conveyed to the bloodstream by the lymphatic vessels

Question 4

Cluster of Differentiation

Answer 4

A protocol used for the identification and investigation of cell surface molecules providing targets for immunophenotyping of cells

Question 5

Leucocytes

Answer 5

cells of the immune system involved in defending the body against both infectious disease

Question 6

Lymphocytes

Answer 6

A cell of the adaptive immune system

Question 7

Cytokine

Answer 7

Signaling molecules secreted by certain cells of the immune system and have a direct effect on other cells.

Question 8

Chemokines

Answer 8

Ability to induce directed chemotaxis in nearby responsive cells

Question 9

Cytotoxic

Answer 9

Toxic to living cells

Question 10

Clonal Expansion

Answer 10

An immunological response in which lymphocytes stimulated by antigen proliferate and amplify the population of relevant cells.

Question 11

Opsonization

Answer 11

The process by which a pathogen is marked for ingestion and destruction by a phagocyte

Question 12

Agglutination

Answer 12

A reaction in which particles suspended in a liquid collect into clumps

Question 13

List and describe the attributes of the adaptive immune response.

Answer 13

-Adaptive immunity: the body’s ability to recognize and defend itself against distinct invaders and their products
-adaptive immunity unlike innate immunity has a resistance to a particular foreign agent (memory), its resistance increases with repeated exposure’s traits are
*Antigenic specificity: has specific responses for specific antigens
*Diversity: can remember and defend against a wide range of pathogens
*Immunologic memory: defense gets stronger upon repeated exposure
*Self-nonself recognition: able to differentiate between normal cells/products in body and those of antigens

Question 14

Define antigens and discuss the role of antigens in the immune response.

Answer 14

*antigens are foreign substances that induce an immune response in the body
1. response in the body their role includes
2. triggering the body to respond and fight
3. being what epitopes recognize
4. can be found in pathogens, food, and dust

*Properties of antigens
1. Molecules the body recognizes as foreign and worthy of attack
2. Recognized by three-dimensional regions called epitopes
3. Include various bacterial components as well as proteins of viruses, fungi, and protozoa
4. Food and dust can also contain antigenic particles

Question 15

List the elements of the adaptive immune response, including cells, organs, tissues, and signaling molecules, and describe their specific roles.

Answer 15

antigens are a foreign substances that induces an immune response in the body their role includes
-triggering the body to respond and fight
-being what epitopes recognize
-can be found in pathogens, food, and dust
-it’s like the key and foundation for shit

the lymphatic system screens tissues of the body for foreign antigens (aka where antigen presentation occurs and transitions from innate to adaptive), it is composed of lymphatic vessels and lymphatic cells, tissues, and organs
-lymph: liquid with similar composition to
blood plasma, arises from fluid leaked from
blood vessels into the surrounding tissues
-lymphatic vessels and flow of lymph: is a
one-way system that conducts lymph from
tissues and returns it to the circulatory
system
-primary lymphoid organs: where things arise
and mature, redbone marrow and thymus
-secondary lymphoid organs: sites of antigen
presentation, lymph nodes, spleen, tonsils,
mucosa-associated lymphatic tissues (MALT)

lymphocytes (aka the cells of the adaptive immune system) 3 major populations exist
T cells: produced in primary lymphoid organs, circulate in the lymph and blood (where they migrate to secondary lymphoid tissue), use TCR receptors on the membranes have cytotoxic versions and helper versions, and are a part of MHC classes I and II
B cells: arise in primary lymphoid organs BUT are found in the secondary ones, not really big on being in the red, major function is differentiation into the plasma cells and the secretion of antigen, contain BCRs that are specific like TCRs
natural killer cells: participate in cytotoxic activity by secreting toxins onto surface of virally infected cells and tumors, recognize abnormal cells by mult mechanisms like reduced MHC I (missing self) and Fc portion of antibodies WHICH makes them non-specific

cytokines are soluble regulatory proteins that act as intercellular signals, they are secreted by various leukocytes

cytokine network is a complex web of signals among all the cells of the immune system
examples of cytokines are…
interleukins (ILs) signal among leukocytes
chemokines are chemotactic cytokines that signal leukocytes to move

Question 16

Discuss antibody structure, including different types, and function.

Answer 16

-Antibodies are immunoglobulins similar to BCR’s
-Secreted by activated B cells called plasma cells
-Identical antigen binding sites and specificity as BCR of activated B cell
-Composed of Fc Body, 2 heavy chains, and 2 light chains
Linked by disulfide bonds
Chains have constant and variable regions-
form binding sites
-Fc body determines the type and function of antibody
-Antibody Function- antigen binding sites complementary to epitopes
-Activation of complement
Neutralization- bind to receptor sites on the
invader
Opsonization-display to phagocyte
Killing by oxidation
Agglutination- makes bacterial cells clump
together, and bind to each other’s
receptors
Antibody-dependent cellular cytotoxicity
-5 classes of antibodies
IgM: 1st antibody produced,
neutralization/agglutination
IgG: most common, longest-lasting antibody,
all functions
IgA: associated with body secretions-
neutralization, agglutination
IgE: response to parasitic infections, allergies
IgD: function unknown

Question 17

Compare and contrast the two classes of MHC molecules.

Answer 17

Major Histocompatibility Complex- antigens bind in the groove of MHC molecules, hold and position antigenic determinants for presentation to T cells
-MHC class 1: these proteins found on all nucleated cells, show self/altered self
Display to CD8+ cytotoxic T cells
-MHC class 2: these are found on antigen-presenting cells (APCs) and B cells, display foreign antigen
Display to CD4+ T helper cells

Question 18

Compare and contrast clonal selection and clonal deletion.

Answer 18

clonal selection explains how a single B or T cell that recognizes an antigen that enters the body is selected from the pre-existing cell pool of differing antigen specificities and then reproduced to generate a clonal cell population that eliminates the antigen.

clonal deletion explains how the body eliminates self-reactive lymphocytes, lymphocytes that react to autoantigens undergo apoptosis; this is a vital part of immune responses

Question 19

Describe the process by which different immune system cells communicate with each other.

Answer 19

• cytokines are soluble regulatory proteins that act as intercellular signals, they are secreted by various leukocytes
• cytokine network is a complex web of signals among all the cells of the immune system
• examples of cytokines are…
  interleukins (ILs) signal among leukocytes
  chemokines are chemotactic cytokines that
  signal leukocytes to move

Question 20

List the receptors and signaling molecules used

Answer 20

BCRs: are specific, each B-cell generates a single BCR
each BCR only recognize one epitope
each B-cell has mult copies of the receptor
membrane bound immunoglobulin
plasma cells secrete soluble form

TCRs: are specific they do not recognize epitopes directly
act primarily against cells that harbor epitopes directly
only bind epitopes associated with a MHC protein

antigens are a foreign substances that induces an immune response in the body their role includes
triggering the body to respond and fight
being what epitopes recognize
can be found in pathogens, food, and dust
it’s like the key and foundation for shit

antibodies are…
-antigen-binding sites are complementary to epitopes (and function in: activation of complement, neutralization, opsonization, killing by oxidation, agglutination, and antibody-dependent cellular toxicity ADCC)
-antibodies are immunoglobulins similar to BCRs
-secreted by activated B cells called plasma cells
-have identical antigen-binding sites and antigen specificity as the BCR of the activated B-cell
-contain heavy and light chain variable regions from binding sites
-Fc body determines type/specific function of antibody
-composed of a Fc body, 2 heavy chains, and 2 light chains (linked by disulfide bonds and chains have constant and variable regions)
-because threats to the immune system are variable, the capabilities of antibodies also have to be variable so there are classes of antibodies. CLASSES are dependent on antigen type, portal of entry, and antibody function needed, 5 classes exist…
1. IgM first antibody produced, good at agglutination and neutralization
2. IgG most common and long lasting antibody, most versatile (all functions)
3. IgA associated with body secretions, good at agglutination and neutralization
4. IgE involved in response to parasitic infections and allergies
5. IgD exact function is not known

Question 21

Describe the main events in cellular and humoral immune responses.

Answer 21

cellular: cells killing other cells (think NK cells, cytotoxic T-cells aka CD8+, and activation of APCs), they respond to and kill viruses, cancer cells, and intracellular bacteria and protozoa

humoral: this is more antibody mediated immunity, B cells and the secretion of antibodies by plasma cells, mounted against exogenous pathogens

Question 22

Discuss the role of memory cells in the immune response, including the primary and secondary immune response.

Answer 22

memory B-cells: produced by B cell proliferation but do not secrete antibodies, they have BCRs complementary to the antigenic determinant that triggered their production, persist for months or years in the lymphoid tissue, and initiate antibody production if antigen is encountered again

memory T-cells: some activated T cells become memory T cells, persist for months or years in lymphoid tissues, immediately functional upon subsequent contacts with epitope specifits to its TCR

Question 23

Compare and contrast the two types of acquired immunity. Differentiate between active and passive.

Answer 23

-naturally acquired immunity is a response against antigens encountered in daily life/nature
-artificially acquired immunity is a response to antigens introduced from a vaccine
-both are further distinguished by…
*active, your cells are doing this and it can get stronger over time (getting sick)
* passive, so they are passively received antibodies from another individual, weakens over time (vaccine and breast milk)

Question 24

Discuss the how the innate and adaptive immune responses work together to fight off infection.

Answer 24

innate acts at first fighting off new pathogens with it’s granulocytes, physical barriers, and chemical barriers. from the innate immune system dendritic cells pass on the antigen information to the adaptive immune system so that the body is able to prevent infection and illness if the pathogen appears again

Question 25

Describe the course of infection from physical barriers at a portal of entry all the way to killing of the microorganism.

Answer 25

the pathogen must first make it to a portal of entry and survive the defenses there, if it enters through a body cavity it must sustain itself through the mucus membranes (getting stuck and then vocalized out, or just dying stuck) and if it enters through the skin it must sustain itself out of the high salt concentration on the skin, lowered pH from sebum, and multiple shedding layers of skin cells. it also must look out for lysozymes, phagocytes, and antimicrobial peptides