IMG56 (3)

21. Central (primary) fymphoid orgąns

-r^are efficient fn expbśing T cellś to foreign antigen. g are the primary site of aritibbdy synthesis and release -•Srfflter biciod and trap blood-bome antigens. tj. provide the mtcroenyfronment for maturation of T and B cells. e tfne the mucosaf surfaces of the body for efficient antigen contact.

22. What Is the first rearrangement that appears in B-celi developrnent?

a.    VD

b.    D J

c.    VD and DJ simultaneous/y

d.    VJ of light Chain

23. Antibod/es are antigen binding proteina that are produced by:

a.    dendritic cells.

b.    B cells.

c.    T ce/is.

d.    monocytes.

24. Humanized monoclonal antibody is:

a.    a chimeric human-mouse antibody where CDRs are grafted from mice and the rest originate from human Ab.

b.    Fc regions of Ab are mouse and Fab fragments are from human. ę. Fc regions are from human and Fab fragments are from mice.

d. a heteroconjugate in which one half is tumor specific mouse antibody and the other half is specific for CD3/TCR complex.

25. A polyclonal antibody response

a.    is not antigen-specific.

b.    is produced only in response to polymeric antigens.

ę. is produced by severaI B cells recognizing different epitopes on the same antigen. d. occurs during the lag phase of the immune response. ę. violates clonal selection.

26. Complement

ą. is a group of active proteolytic enzymes found in serum.

b. is secreted by macrophages and hepatocytes in response to antigen binding.

ę. participates in both innate and adaptive immune responses.

d. pręventś łysis of viriis-ińfected cells.

ę. Ali of the above statements about complement are true.

27. Complement is involved in all of the following excepl

a. attraction of neutrophils to an infection site. increased presertce of serum proteins in the infected tissues. j?'1y$is ofbacteria in the absence of specific antibodies.

Hopsonization of microorganisms for phagocytosis.

§ sensitization of T cells to antigen