[The role of costimulatory molecule 4-1BB and CD28 in activating of various T cell subsets from human peripheral blood].

Aim: To explore the role of 4-1BB molecule in the activation and proliferation of CD4(+) T cells and CD8(+) T cells and compare it with that of CD28 molecule.

Methods: Human peripheral blood mononuclear cells (PBMCs) were stimulated in-vitro with anti-CD3 mAb. Anti-4-1BB mAb and anti-CD80 mAb were added so as to block respectively costimulatory signals of 4-1BB/4-1BBL and CD28/B7-1. Flow cytometry was used to detect the proliferation ratio of CD4(+) T cells and CD8(+) T cells and the secretion of IFN-gamma.

Results: When 4-1BB/4-1BBL and CD28/B7-1 signals were blocked by anti-4-1BBL mAb and anti-CD80 mAb, the proliferative response and the secretion of IFN-gamma by CD4(+) T cells and CD8(+) T cells were obviously decreased. In the group stimulated with anti-CD3 mAb only, the ratio of CD8/CD4 T cells was 1.98+/-0.06. In the groups blocked with anti-4-1BBL mAb and anti-CD80 mAb, the ratios were 0.96+/-0.03 and 2.69+/-0.16, respectively.

Conclusion: 4-1BB molecule could provide a costimulatory signal for activation and proliferation of CD4(+) T cells and CD8(+) T cells. The costimulatory signal mediated by 4-1BB molecule could mainly induce the proliferative response of CD8(+) T cells, while that mediated by CD28 molecule could induce the activation of CD4(+) T cells mainly.