The bispecific CD4-based CARs such as CD4–MBL (67, 68) are advantageous in that the second moiety prevents the CD4 from acting as an HIV entry receptor on CAR-expressing CD8+ T cells; however, an additional mode of protection is required for CAR-expressing CD4+ T cells, which are susceptible to infection via the endogenous CD4 molecules. The gene discussed is CD4; the disease is infection.