Disease Associated with Immune System - Medical Science

Q1:

X-linked hyper IgM syndrome, resulting in high levels of serum IgM and low levels of serum IgG, is caused by a defect in CD40L expression. The specific immune event that would be prevented by a defective CD40L would be

A activation of B cells by T-independent antigens

B failure of B cells to provide co-stimulation for Th2 activation

C failure of Th2 cells to provide co-stimulation for B cell isotype switching

D failure of Th2 cells to provide co-stimulation for B cell proliferation

ANS:C - failure of Th2 cells to provide co-stimulation for B cell isotype switching

No answer description is available.