11 Antibodies

Question 1

what are the types of binding antibody family to proteins

Answer 1

conformational determinant

linear determinant

Question 2

Conformational determinant

Answer 2

when denatured determinant lost by denaturation

- antibodies bind only when the protein

Question 3

Linear determinant

Answer 3

when denatured:

• Ig binds to determinant in denatured protein only
• Ig binds to determinant in both native in denatured protein

Question 4

Antibody diversity

Answer 4

B cell precursor
Antibody rearrangement is random (only one of each segment)
Two segments join in heavy chain gene (D-J, then V to D) and the DNA in between is cut
Remove introns
Forms mRNA
mRNA translates into light chain

Question 5

Antibody binding diversity

Answer 5

DNA segments of heavy chain are rearranged to produce gene V, D, J and C

Question 6

Can B cells expressed more than one VH domain

Answer 6

VH domain is rearranged the other loci stops rearranging = Allelic exclusion
Therefore, a given B cell clone only expresses ONE Variable domain

Question 7

Why during second response the antibody is ‘better’

Answer 7

• secondary response is mainly mediated by memory cells
• memory cells are product of T and B cell differentiation
• after second activation with antigen memory cells undergo the process of somatic mutation of their variable region gene
• after affinity selection, positive selected clones expand and differentiate into memory cells
• somatic mutations

Question 8

Do Vh domains improve with time

Answer 8

Accumulating mutations
Increasing binding affinity to the molecule
Why there are sometimes more vaccinations – to try improve the affinity towards the antigen

Question 9

Events that change Ab response from just IgM

Answer 9

• after antigen encounter some B cells switches irreversibly to other downstream antibody isotopes (IgG, A and E)
• once switched cells lose ability to express IgM and IgD
• those alterations occurs at DNA level similar to V gene rearrangement

Question 10

what drives class switching

Answer 10

cytokines

Question 11

specific opsonins

Answer 11

antibodies

Question 12

non-specific opsonins

Answer 12

complement system, fibronectin, lectins, fibrinogen, C-reactive proteins

Question 13

Recognition driven by complement

Answer 13

complement activation (labelling and lysis)
- immune adherence