Patients with the Disease X-Linked Lymphoproliferative Syndrome (XLP) Lack Expression

Patients with the disease X-linked lymphoproliferative syndrome (XLP) lack expression of the small adapter protein SAP, which associates with receptors of the SLAM family. One characteristic of this disease is an inability of cytotoxic T cells to control infections with a virus, Epstein-Barr virus (EBV) , that replicates in B cells. This defect in control of EBV results from:

A) A defect in antibody responses to EBV due to impaired T cell help for B cells
B) A defect in adhesion of cytotoxic T cells to EBV-infected B cells
C) Impaired migration of activated B cells to the germinal center
D) Impaired survival of activated B cells, normally induced by CD40 stimulation
E) A defect in T_FH differentiation, normally induced by ICOS on B cells binding to ICOS-ligand on T_FH cells