CXCR5 and infection: In the case of our CD4-MBL CAR/CXCR5 T cells, the lack of persistence of the cells in the study animals may be a complex interaction between the ADA in the serum and, possible infection of the CAR T cells by SIV, exhaustion of the CAR T cells post-treatment, the low level of antigen present at the time of ART release, or potential cell-mediated CAR-T cell clearance.