Effect of CD4 + Memory T Cells on Rejection Response of Ectopic Heart Transplantation in Mice

Abstract

Background CD4 + memory T cells mediate resistance of the body to infection by exotic pathogens. This study investigated the effects of alloreactive CD4 + memory T cells on acute graft rejection responses toward ectopic hearts in the abdominal cavities of mice. Methods BALB/C mice were used as recipients and C57BL/6 mice as donors. The animals in the CD4 + memory T-cell group were infused with CD4 + memory T cells, those in the other group were infused with nonsensitized CD4 + T cells, and those in the control group received no CD4 + T cells. Heart transplantation was performed at 3 weeks after the cell infusion with cyclosporine administered beginning 1 day before transplantation via intraperitoneal injection. Results The survival among the CD4 + memory T-cell group was significantly shorter than that of the nonsensitized CD4 + T-cell group or the control group ( P < .01; n = 10). There was no significant difference between the survival times of the nonsensitized CD4 + T-cell group and the control group ( P > .05; n = 10). On the 5th day after the transplantation of heart, the histologic grades of the nonsensitized CD4 + T-cell and the blank control group were lower than those of the CD4 + memory T-cell group. There was no significant difference in the histologic grades between the nonsensitized CD4 + T-cell and control groups. Conclusion The CD4 + memory T cells that mediate acute rejection of allografted hearts are insensitive to cyclosporine.