Interleukin-2 receptor beta and gamma chain dysregulation during the inhibition of CD4 T cell activation by human immunodeficiency virus-1 gp120.

Abstract

We have observed that CD4 T lymphocytes from human immunodeficiency virus (HIV)-infected patients marginally express interleukin-2 receptor (IL-2R) beta and IL-2R gamma chains which are essential for IL-2 signal transduction. To analyze this observation further, we studied the influence of gp120 on the cell surface expression of IL-2R beta and IL-2R gamma by purified CD4 lymphocytes in vitro. Cross-linking of the T cell receptors of these lymphocytes initiates entry into the cell cycle as measured by CD69 and CD71 cell surface expression and [3H]thymidine incorporation. It also induces the cell surface expression of IL-2R beta and IL-2R gamma. We have shown that treatment of the CD4 T lymphocytes with HIV-1 gp120 before anti-CD3 stimulation impedes cell cycle progression as measured by reduced CD71 expression and inhibition of [3H]thymidine incorporation. Furthermore, cell surface expression of IL-2R beta and IL-2R gamma subunits, which from the functional intermediate-affinity IL-2R, are significantly inhibited. More importantly, addition of exogenous IL-2 does not restore the proliferation of the CD4 T cells treated with gp120, suggesting that cells are anergic and/or that the remaining IL-2R are not functional. This is the first study of IL-2R beta and IL-2R gamma dysregulation in the context of HIV infection and shows that CD4 is also involved in IL-2R expression.