Functional analysis of alloreactive memory CD4+ T cells derived from skin transplantation recipient and naïve CD4+ T cells derived from untreated mice

Abstract

Background: Memory T cells (T(M)s) exhibit differential susceptibility to many immunomodulatory strategies that induce immunologic tolerance in naïve T cells, which are believed to be an important barrier to inhibiting rejection and inducing tolerance. As skin grafts are a common model for acquiring T(M)s, we evaluated function of T(M)s derived from skin grafts. We also assessed the modulatory effects on memory T cells function of the microRNAs miR-155 and miR-181a, which are involved in regulating cytokine secretion and TCR sensitivity to antigen, respectively.

Methods: Memory CD4(+) T cells derived from skin-graft recipient mice, and naïve CD4(+) T cells from untreated mice, were isolated by negative magnetic selection, and then stimulated with dendritic cells pulsed with donor-specific antigens. Effector function and regulating mechanisms were assessed.

Results: In contrast to naïve CD4(+) T cells, CD4(+) T(M)s stimulated with donor-specific antigen could quickly generate effector function in terms of proliferation and cytokine secretion; miR-155 and miR-181a levels in CD4(+) T(M)s rapidly increased during immune response compared to naïve CD4(+) T cells.

Conclusion: Memory CD4(+) T cells derived from skin grafts could be used as an experimental tool for evaluating effects of different immune-modulating strategies on T(M)s. Levels of miR-155 and miR-181a up-regulated quickly in T(M)s, which could be an important mechanism by which T(M)s mediate immune responses rapidly.