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

ANSWER DOWNLOAD EXAMIANS APP

Disease Associated with Immune System
Bone marrow given to an infant with SCID must

come from a donor that shares some MHC alleles with the recipient
contain mature T cells that can begin making immune responses immediately
be irradiated to eliminate GVHD
come from one of the child's parents

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

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

ANSWER DOWNLOAD EXAMIANS APP