A child has a history of recurrent infections with organisms having polysaccharide antigens (i.e., Streptococcus pneumoniae and Hemophilus influenzae). This susceptibility can be explained by a deficiency of A. C3 nephritic factor
B. C5
C. IgG subclass 2
D. myeloperoxidase in phagocytic cells
E. secretory IgA
Selective IgA deficiency: E, remember Tx with ATBs not Igs (possibility of anaphylaxis)
Ans is E
I agree with gautedoc.
i think its D..defect in phagocytic cells causing capsulated organisms infections
why not C?
igG is opsonin causes phagocytosis.
might be inhibit phsgocytosis of encapsulated bacteria,just a guess
whats the right ans?
The correct answer is C. IgG is the predominant antibody in the secondary immune response. IgG subclass 2 is directed against polysaccharide antigens and is involved in the host defense against encapsulated bacteria.
C3 nephritic factor (choice A) is an IgG autoantibody that binds to C3 convertase, making it resistant to inactivation. This leads to persistently low serum complement levels and is associated with Type II membranoproliferative glomerulonephritis