Antibody-suppressor CXCR5 + CD8 + T cellular therapy ameliorates antibody-mediated rejection following kidney transplant in CCR5 KO mice.

CCR5 KO kidney transplant (KTx) recipients are extraordinarily high alloantibody producers and develop pathology that mimics human antibody-mediated rejection (AMR). C57BL/6 and CCR5 KO mice (H-2 b ) were transplanted with A/J kidneys (H-2 a ); select cohorts received adoptive cell therapy (ACT) with alloprimed CXCR5 + CD8 + T cells (or control cells) on day 5 after KTx. ACT efficacy was evaluated by measuring posttransplant alloantibody, pathology, and allograft survival. Recipients were assessed for the quantity of CXCR5 + CD8 + T cells and CD8-mediated cytotoxicity to alloprimed IgG + B cells. Alloantibody titer in CCR5 KO recipients was four-fold higher than in C57BL/6 recipients. The proportion of alloprimed CXCR5 + CD8 + T cells 7 days after KTx in peripheral blood, lymph node, and spleen was substantially lower in CCR5 KO compared to C57BL/6 recipients. In vivo cytotoxicity towards alloprimed IgG + B cells was also reduced six-fold in CCR5 KO recipients. ACT with alloprimed CXCR5 + CD8 + T cells (but not alloprimed CXCR5 - CD8 + or third-party primed CXCR5 + CD8 + T cells) substantially reduced alloantibody titer, ameliorated AMR pathology, and prolonged allograft survival. These results indicate that a deficiency in quantity and function of alloprimed CXCR5 + CD8 + T cells contributes to high alloantibody and AMR in CCR5 KO recipient mice, which can be rescued with ACT.