Disease Associated with Immune System
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

failure of Th2 cells to provide co-stimulation for B cell proliferation
failure of B cells to provide co-stimulation for Th2 activation
failure of Th2 cells to provide co-stimulation for B cell isotype switching
activation of B cells by T-independent antigens

ANSWER DOWNLOAD EXAMIANS APP

Disease Associated with Immune System
Chronic granulomatous disease results from a failure to perform oxidative burst. This deficiency would be most likely to interfere with

macrophage intracellular killing of bacteria
dendritic cell activation to become a mature APC
CTL killing of viruses
infected cell processing of virus peptides

ANSWER DOWNLOAD EXAMIANS APP