[Proliferative response of CD62L(-)/CD62L(+) T cells in mice to antigen stimulation]

The aim of this study was to investigate the ability of CD62L(-)/CD62L(+) T cells responding to antigens so as to explore the role of CD62L in GVHD. The T cells were stimulated by DCs-presenting specific antigen hCD4; the expression of CD62L on surface of T cells was detected by flow cytometry, the CD62(-) T/CD62L(+) T cells were gained by sorting selection method, then were stimulated with a new antigen (freeze-thaw antigen of EL4 cells), and the proliferation activity of CD62L(-) and CD62L(+) T cells was detected by flow cytometry after stimulating with different antigens at twice. The results showed that after stimulating with antigen, the expression level of CD62L(+) on surface of T cells was down-regulated from 60.34% to 36.75%, and the expression of CD62L(-) on surface of T cells increased from 30.04% to 63.15%. Compared with cells counts in area with high CFSE (M1), the average percentages of CD62L(+) T cells under stimulating with specific antigen (hCD4) on days 1 and 6 were (87.88 +/- 1.08)% and (86.88 +/- 1.46)% respectively (p > 0.05), and the average percentages of CD62L(+) T cells after stimulating with specific antigen on days 1 and 6 were (84.52 +/- 2.73)% and (84.21 +/- 2.33)% respectively (p > 0.05), there was no significant difference between two T cell groups on days 1 and 6. After stimulating with non-specific antigen, the average percentages of CD62L(+) T cells in MI area on days 1 and 6 were (76.49 +/- 2.41)% and (22.25 +/- 3.29)% respectively (p < 0.001), the average percentages of CD62l(-) T cells under conditions mentioned above were (77.35 +/- 3.82)% and (74.76 +/- 3.90)% respectively (p < 0.05). The results indicated that the proliferation activity of CD62L(+) T cells appeared, and the proliferation of CD62L(+) T cells did not occur. It is concluded that the CD62L(-) T/CD62l(+) T cells are gained in vitro, no proliferation reaction occurred in these two kinds of cells under stimulation of specific antigen, but the mitotic proliferation occur in CD62L(+) T cells under stimulation of nonspecific antigen, while no this reaction exists in CD62L(-) T cells under this condition. These results provide a new thinking to obtain the CD62L(-) T cells in vitro, to selectively eliminate the CD62L(+) T cells from graft and to decrease occurrence of GVHD in clinical practice.