Adaptive & Specific Immunity

Question 1

Humoral Immunity

Answer 1

protective molecules (mainly antibodies) carried in the fluids of the body

Question 2

Cell-Mediated Immunity

Answer 2

The type of immune responses brought about by T cells, such as cytotoxic, regulatory, and helper effects. An activated T cell interacts directly with antigen-bearing cells in order to bring about its end result

Question 3

Antigen

Answer 3

any cell, particle, or chemical that has properties that allow it to stimulate a specific immune response by B cells or T cells

Question 4

Antibody

Answer 4

a large protein molecule evoked in response to an antigen that interacts specifically with that antigen

Question 5

Titer

Answer 5

a measure of antibody levels in a patient’s serum or specimen, as determined by agglutination methods

Question 6

Seroconversion

Question 7

T marker (receptor)

Answer 7

binds free antigens

Question 8

B marker (receptor)

Answer 8

bind processed antigens together with MHC molecules on antigen presenting cells

Question 9

Immunocompetence

Answer 9

the ability of the body to recognize and react with multiple foreign substances

Question 10

Antiserum

Answer 10

Antibody-rich serum derived from people who have recovered from specific infections such as hepatitis; sometimes taken from the blood of animals deliberately immunized against an infectious or toxic antigen. Used in passive immune therapy

Question 11

Origin of all cells

Answer 11

all cells rise from stem cells in bone marrow

Question 12

Properties of B cells

Answer 12

• differentiate in bone marrow
• humoral response: stimulated by an antigen to produce specific antibodies
• defends against bacteria, protozoans, and fungi

Question 13

Properties of T cells

Answer 13

• differentiate in the thymus
• cell-mediated response: stimulated by an antigen inside a host cell or in a cell membrane
• defends against viruses and cancer cells

Question 14

Properties of B AND T Cells

Answer 14

• Found in lymphatic tissue
• Migrates to secondary lymphoid tissue (lymph nodes)
• Millions of distinct B & T cells develop and migrate to lymph nodes, spleen, GALT (SALT, MALT)

Question 15

MHC-1

Answer 15

markers display unique characteristics of “self” and allow for recognition

Question 16

MHC-2

Answer 16

• receptors that recognize and react with “non-self” (foreign antigens)
• Found on Antigen Presenting Cells (APCs): macrophages, dendritic, and B cells; important for presenting to T cells

Question 17

Receptor Gene Rearrangement

Answer 17

• We have 500+ genes that code for the variable tips of all antibodies. 100s of genes code for millions of distinct surface receptors
• During early embryonic development, stem cells rapidly differentiate
• Early embryonic lymphocyte genes randomly shuffle generating millions of new gene combinations -> massive variation before you are even born
• We have everything we need; it;s just a matter of using them at the moment we need them

Question 18

Clonal Deletion Theory

Answer 18

• Lymphocytes do not attack our own cells normally
• during embryonic development all lymphocytes with “self” antigens ar removed (organism develops tolerance to itself)
• Result: you are born with a passive pool of genetically distinct, immature lymphocytes called clones which will protect you from pathogens for the rest of your life. Each clone bears a different receptor which will react with only a single type of antigen.
• clones carrying a specificity for self molecules are eliminated and immune tolderance is achieved. Result = a repertoire of lymphocyte clones each with unique receptors

Question 19

Clonal Selection Theory

Answer 19

• Explains development of lymphocyte specificity and variety during maturation of the immune system
• Lymphocytes circulate in the lymphatic organs, encounter an invading antigen, and only clones with matching surface receptors bind.
• Selected clones proliferate (multiply by mitosis)
• Selected clones migrate home to the lymphatic organs ready to encounter antigens

Question 20

B-Cell Clonal Selection Theory

Answer 20

• B-cell binds to antigen and responds by proliferating
• Some b-cells turn into Memory Cells (which are kept forever) and some turn into Plasma Cells (which are the ones that FIGHT by secreting antibodies into circulation)
• T-cell clones respond to specific antigens in a similar way

Question 21

self-tolerance

Answer 21

the ability of the immune system to recognize self-produced antigens as a non-threat while appropriately mounting a response to foregin substances

Question 22

Characteristics of Antigens

Answer 22

• Large, complex protein, mwt = 10,000+ (sometimes a lipo/glycol/nucleoprotein or a polysaccharide)
• located on the surface of all cells and viruses
• recognized by Immune System as “non-self”
• each antigen is made of many epitopes: the portion of a foreign cell or cirurs that is the precise stimulus of an immune response

Question 23

Haptens

Answer 23

• molecules that are too small to elicit an immune response
• a single epitope that may bind to a carrier group (e.g. plasma protein)
• Ex: penicillin, household chemicals)

Hydralazine can cause drug-induced Lupus erythematosus

Question 24

The Humoral Response Antigen Entrance, and Processing Clonal Selection

Answer 24

1. Macrophages, b-cells and t-cells work together
2. specific B-lymphocytes bind to pathogen surface receptors (PAMPs)
3. B-cell clones are selected and activated
4. Selected b-cell rapidly divides
5. product cells mature into plasma and memory b-cells
6. plasma cells synthesize and release antibodies (2000 Ab/sec)

Question 25

Entrance and Processing of Antigens

Answer 25

1. Macrophage/Dendritic Cell (APC) phagocytizes pathogen
2. Processed antigen is presented on APC’s sticky membrane surface complexed with MHC-2. IL-1 is released.
3. Helpter T-cells recognize and bind to foreign antigen/MHC complex. IL-2 is released
4. Activation of T-cells, proliferation of B-cells