Med Micro 6.1 - Specific Defense Part 1B (AB class)

Question 1

Main cellular components of humoral immune response involved in defense

Answer 1

B cells and plasma cells

Question 2

Plasma cells

Answer 2

Descendants of B cells (clonal expansion) that secrete ABs that act against extracellular pathogens

Question 3

What do antibodies bind to?

Answer 3

To epitopes (specific part of antigens)

Question 4

Cell mediated Immunity

Answer 4

Descendants of T lymphocytes do not involve antibodies and attack intracellular pathogens; Long lived descendants of B and T cells provide immunological memory

Question 5

How are antigens recognized? Which produce the better immune response?

Answer 5

By their epitopes, 3D regions. Large ones are better immunogens (important for vaccines, needs to be big enough)

Question 6

Another name for Epitopes

Answer 6

aka antigenic determinant

Question 7

Endogenous, exogenous, and auto-antigens and their responses

Answer 7

Endogenous have a T cell response (often a B one too), exogenous have a B cell response, auto-antigens identify self

Question 8

Conjugate vaccines

Answer 8

If antigen is small, we link many many copies in sequence to generate a good response

Question 9

Linear and conformational epitope

Answer 9

Linear is a.a. sequence, conformational is 3D (more than sequence - most are this type). About 15 a.a. when defined by spatial contact of antibody and epitope; of the 15 only 5 are strongly involved in binding

Question 10

B lymphocytes

Answer 10

Found primarily in the spleen, lymph nodes, red bone marrow, and Peyer’s patches; small % in the blood; naïve and activated (gets primed first then active)??; mature into plasma or memory cells once activated; secretes antibodies

Question 11

Antibody functions

Answer 11

Neutralization, opsonization (macrophage recognize constant region on an AB), agglutination (cross-linking and precipitate out), antibody-dependent cellular cytotoxicity (ADCC)

Question 12

ADCC

Answer 12

Antibody-dependent cellular cytotoxicity. NK cell secretes perforin and granzyme when it recognizes constant region of AB. Perforin makes channel, granzyme enters and triggers apoptosis

Question 13

Passive immunotherapy

Answer 13

Get an injection of antibodies developed in another host which will help neutralize a toxin etc. Won’t work a second time because we will have a immune response to the antibody.

Question 14

5 isotypes of antibodies immunoglobulins. What determines which gets used?

Answer 14

IgG, IgA, IgM, IgE, IgD. The class involved in the immune response depends on the type of foreign antigen, the portal of entry, and the antibody function needed

Question 15

IgG function and location

Answer 15

Complement activation, neutralize, opsonize, produce H2O2, agglutination, ADCC; only one that can cross placenta to fetus. In serum and mast cell surfaces, can leave blood

Question 16

IgA function and location

Answer 16

Neutralize and agglutination; dimer is secretory antibody (often has secretory component to protect is from intestinal enzymes). Monomer in serum, dimer in mucous membrane, tears and milk

Question 17

IgM function and location

Answer 17

Monomer acts as BCR; pentamer is secreted and acts in complement activation, neutralization, agglutination. First one to be made. In serum

Question 18

IgE function and location

Answer 18

in allergic responses or worms, bound to mast cells; it releases histamine from basophils and mast cells, and release antiparasitic molecules from eosinophils. In serum and mast cell surfaces.

Question 19

IgD function and location

Answer 19

Unknown, perhaps just acts as BCR. On B cell surface, not secreted

Question 20

Which AB class is the longest lasting and most abundant? Which is least abundant?

Answer 20

IgG, makes up about 80% and lasts longest. IgD is least abundant in serum, IgE is a close second.

Question 21

Which AB class has J chains?

Answer 21

IgM and IgA. J stands for joining (not same as J segment of AB!). IgM is pentamer, IgA is sometimes dimer