IMG57 (4)

28. As corrtplenient »s aćtivated by compfexas of antibody-coated bactoria, bystander tysis of naarby nost cells is prevented by

8- 0 fańg+liyed thioester bond on active complamant proteins & covalent attachment of alt activo compłcment proteina to the pathogen surface £ plasma proteina that inactivate the anaphyiatoxina 4 proteina on host celi membranes that inhibit MAC formatron.

§■ the slow catalytic ratęs of compiement proteases

29. An antibody Fab contalns

8 complementarity determlning regłons. b. H and L Chain yar/able regions.

£. one antigen binding region.

d.    one H-L interchain disulfide bond.

e.    afi of the above.

30. Which statement about antigen epitopes is FALSE?

ą. An epitope may be shared by two different antigens. b. A protein molecule usually contains multiple epitopes.

£. B ce//s bind only processed antigen epitopes.

d.    Epitopes may be linear (composed of sequential amino acids) or assembled by protein folding from amino acids far apart in the protein primary amino acid sequence.

e.    Some epitopes are morę immunogenic than others.

31. The gene segments needed to encode the variable region of a k Chain are

a.    one Jk plus one Dk.

b.    one Jk plus one Ck.

c.    one Vk plus one Dk.

d.    one Vk plus one Jk.

e.    one Vk plus one Jk plus one Dk.

32. Isotype switching

a.    changes the leader sequence exon so the antibody is secreted.

b.    improves the antigen binding specificity of an Ig molecule.

g. increases the affinity of antibodies in a process called affinity maturation.

d.    increases the functional diversity of Ig molecules.

e.    occurs randomly between switch regions.

33. B celi differentiation begins with the expression of

a membranę p chain + surrogate L Chain. b. membranę IgD. g. Membranę IgM. d. germline IgM. e RAG-1, RAG-2 and TdT.

34. Which statement about B celi deve!opment is FALSE? a. Cells which fail to synthesize and express p chains usually die.

to 10.10

Ż- ONA joining event in Ig genes has a 67% probability of resulting in a nonproductive rearrangement The earliest developing B celi which could be stained with FITC-anti-p chain would be a pro B celi.

The earliest developing B celi which could be stained with FITC-anti- k chain would be an icgmature B ceft The enzyme which can add nucleotides not encoded in the DNA to Ig genes during recombination is TdT