Objective   To explore the inhibition factors which CD4 ⁺T lymphocyte secreted after infection with SIVmac239, whether or not these factors Could inhibit the Blymphocyte proliferation activity and it's inhibition mechanism, some helpful clue for pathogenology research of AIDS would be supplied.

  Methods   Proliferation activity of MM133 cells treated by the supernatant of C8166 cells infected SIVmac239 tested by MTT assay. The inhibition of DNA synthesis of supernatant of C8166 cells infected by SIVmac239 on B cells estimated by ³H thymidine uptake assay. Whether or not the apoptosis happened when the DNA synthesis inhibiton judged by DNA fragmentation detection. Cyclin D1 expression was examined through western blot assay.

  Results   SIVmac239 could stimulate CD4 ⁺T lymphocyte to secret some inhibitant factors for the macques B lymphocyte. These factors could inhibit the DNA synthesis of B cells through ³H thymidine uptake assay, electrophoresis result did not show DNA ladder, there was not Cyclin D1 bands on western blot assay for the concentration of 25% and 12.5% supernantant of C8166 infected by SIVmac239.

  Conclusion   CD4⁺T lymphocyte infected by SIVmac239 can produce some inhibitant factors on the macques B lymphocyte; these factors also can inhibit the DNA synthesis of B cells, but the factors do not induce the apoptosis of B cells. The major mechanism of inhibition of the factors on the B cells is to arrest the cells in G1 phase duing cell cycling. A new phenomenon has been found in this experiment, B cells can not be infected by SIVmac239, but they will be arrested in G1 phase by some factor produced by CD4 ⁺T Lymphocyte infected with SIVmac239. Thus the function of B lymphocytes and the humoral immunity may be limited.