Lecture 10

Question 1

Give the 5 classes of antibodies.

Answer 1

IgD, IgM, IgG, IgA, IgE

Question 2

IgD

Answer 2

A monomer attached to the surface of B cells, important in B cell activation.

Question 3

IgM.

Answer 3

A pentamer released by plasma cells during the primary immune response

Question 4

IgG

Answer 4

A monomer that is the most abundant and diverse antibody in primary and secondary response; crosses the placenta and confers passive immunity.

Question 5

IgA

Answer 5

A dimer that helps prevent attachment of pathogens to epithelial cell surfaces.

Question 6

IgE

Answer 6

A monomer that binds to mast cells and basophils, causing histamine release when activated.

Question 7

Antibodies themselves don’t destroy ______; they instead _______and ____ it for _________.

All antibodies form an _________________ complex.

Answer 7

antigen; inactivate; tag; destruction

antigen-antibody (immune)

Question 8

Defensive mechanisms used by antibodies are… (4)

Answer 8

neutralization; agglutination; precipitation; complement fixation

Question 9

Explain neutralization.

Answer 9

Antibodies bind to and block specific sites on viruses or exotoxins…preventing these antigens from binding to receptors on tissue cells.

Question 10

Explain agglutination.

Answer 10

Antibodies bind the same determinant on more than one antigen.
Makes antigen-antibody complexes that are cross-linked into large lattices.
Cell-bound antigens are cross-linked, causing clumping (agglutination).

Question 11

Explain precipitation.

Answer 11

Soluble molecules are cross-linked into large insoluble complexes.

Question 12

What is complement fixation?
What does it enhance?
Uses a positive feedback cycle to promote ____________.

Answer 12

The main mechanism used against cellular antigens. Antibodies bound to cells change shape and expose complement binding sites. This triggers complement fixation and cell lysis.
Enhances the inflammatory response.
…phagocytosis

Question 13

Which antibody defenses enhances to phagocytosis? Enhances Inflammation? Leads to Cell lysis?

Answer 13

Neutralization, agglutination, precipitation and complement
Complement
Complement

Question 14

Describe the immunological memory of the primary immune response.

Answer 14

Cellular differentiation and proliferation, which occurs on the first exposure to a specific antigen.
Lag period: 3 to 6 days after antigen challenge.
Peak levels of plasma antibody are achieved in 10 days.
Antibody levels then decline .

Question 15

Describe the immunological memory of the second immune response.

Answer 15

It is the re-exposure to the same antigen.
Sensitized memory cells respond within hours.
Antibody levels peak in 2 to 3 days at much higher levels.
Antibodies bind with greater affinity, and their levels in the blood can remain high for weeks to months.

Question 16

What are the types of humoral immunity?

Answer 16

Active (naturally and artificially) and passive humoral immunity

Question 17

What is active immunity? 2 types.

Answer 17

When B cells encounter antigens and produce antibodies against them.
Naturally acquired – response to a bacterial or viral infection
Artificially acquired – response to a vaccine of dead or attenuated (weakened) pathogens

Question 18

What is passive immunity? 2 types.

Answer 18

When B cells are not challenged by antigens. Immunological memory does not occur.
Naturally acquired – from the mother to her fetus via the placenta or colostrum
Artificially acquired – from the injection of serum, such as gamma globulin