Direct mechanisms of HIV infection include interactions with surface molecules on B lymphocytes, including: (i) viral glycoprotein gp120 interaction with membrane immunoglobulins from the variable heavy chain 3 (VH3) family; (ii) interaction with C-type lectin receptors on B lymphocytes [100,101]; (iii) binding to CD1 in B cells; and (iv) CD21-dependent interactions [102]. This evidence concerns the gene CR2 and HIV infectious disease.