A 2-Year-Old Boy Suffers from Recurrent Bacterial Infection of His

Multiple Choice

A 2-year-old boy suffers from recurrent bacterial infection of his ears,sinuses,lungs,and skin;laboratory studies indicate absence of sialylated Lewis X on his leukocytes.He is diagnosed with leukocyte adhesion deficiency type 2 (LAD-2) .Which type of adhesive interaction required for leukocyte migration is defective in this boy?

A) E-selectin ligand binding to E-selectin
B) CD4 binding to class II MHC
C) VLA-4 binding to VCAM-1
D) Ig Fc receptor binding to Ig-coated cells
E) LFA-1 binding to ICAM-1