It is noteworthy that among these studies, both Chowdhury (17) and Misumi (35) found that absence of antigen specific B cells either from SCID mice without B cells or treatment of anti-CD20 mAb did not impact the priming of CD4 T cells in viral infection but impaired the development and effector function of memory CD4 T cells. This evidence concerns the gene CD4 and viral infectious disease.