Lecture 19 - B Lymphocytes and Antibodies

Question 1

Interferons?

Answer 1

interfere w virus replication, detects ribosome usage by virus, induce transient virus resistance in cells surrounding infected, and activate natural killer cells

Question 2

Pro-inflammatory cytokines (interleukin and TNF)?

Answer 2

tissue repair - fibroblast proliferation, bone reabsorption, prostaglandin and collagenase synthesis

Question 3

Chemokines?

Answer 3

affect neutrophil migration and allergic inflammation, can be haemiopoetic (from bone marrow)

Question 4

Antibody structure - light chain?

Answer 4

constant region proximal, distal variable region (with hypervariable regions)

Question 5

Antibody structure - heavy chain?

Answer 5

inf. an proximal constant region (CH2 is complement-binding region), distal variable regions, hinge region - bottom (CH2 and 3) is Fc region

Question 6

Antibody classes?

Answer 6

differentiated by amino acid sequences of constant heavy chains, named by heavy chain isotypes: IgM, IgG, IgA, IgD, IgE

Question 7

Antibodies around birth?

Answer 7

maternal IgG across placenta in utero and diminish over first 10 months (protected from infection), IgA in breast milk, post natal rise in IgG after first month, IgM progression starts prior to birth

Question 8

B Cell Clonal activation?

Answer 8

antigen detected, mediation with T helper cell (aided by CD40->CD40L interaction and cytokines) to proliferate and differentiate into plasma and memory cells

Question 9

Antibody effects?

Answer 9

blocking and neutralising (prevent attachment and entry, immobilise flagella), agglutination and opsonisation (assist phagocytosis), antibody-dependent cellular cytotoxicity, complement activation

Question 10

Complement activation?

Answer 10

C3b attachment to antibody-antigen complex triggering opsonisation and lysis; C3a acts to promote chemotaxis

Question 11

IgM?

Answer 11

first in primary (naive) antibody response, effective aggultinator and complement activator, defence of blood-borne spread of infection (bacteria)

Question 12

IgG?

Answer 12

most of Ig pool, diffuses into extravascular spaces, antitoxic, effective against viruses, good complement, strong binding and activation of phagocytosis

Question 13

IgA?

Answer 13

predominate of mucus, protection of external body surfaces, surface protection of gut, resp. and GU tracts

Question 14

IgD?

Answer 14

trace amounts, found on surface of B cells to activate naive response

Question 15

IgE?

Answer 15

trace amounts, binds strongly to mast cells, important in parasitic infections and allergies