NBME1-section2#12 - doubleblessing

[ArchivalUser]

After a full course of immunization with a new vaccine consisting of a recombinant polypeptide. 10% of adults fail to make antibody to the polypeptide. The norespnders have an increased frequency of one HLA type. What is the most likely explanation for the failure of this group to respond to immunization?
a.. failure of B lymphocytes to recongnize the polypeptide
b. failure to T lymphocytes to recognize the polypeptide
c. lack of class I MHC presentation of the polypeptide
d. lack of class II MHC presentation of the polypeptide

[ArchivalUser]

bbbb???

[ArchivalUser]

d. lack of class II MHC presentation of the polypeptide

[ArchivalUser]

its humeral immunity cause its failure of Ab formation .. ithink A is rt correct me if im wrong please

[ArchivalUser]

usmle light
B cells cannot produce Abs only with help of TH2
If any produced are IgM and nonspecific without memory
I hope I am clear

[ArchivalUser]

so the answer is ?????

[ArchivalUser]

ahhh D

[ArchivalUser]

i checked kaplan generation of humoral effector mechanism it says :B-cells need two signals for fully differentiatio into antibodysecreting cell and memory cell : 1st after leaving the bone marrow it enter follicular area of lymph node and spleen where it cross -link with Ag ....the 2nd signal is congugation with TH ie MHC class2 and the release of its cytokines..