Altered cytokine genes expression by conA-activated spleen cells from mice infected by lymphocytic choriomeningitis virus.

The intravenous injection of mice with lymphocytic choriomeningitis virus (LCMV) induces a rapid and long-lasting immunodeficiency. T lymphocytes from 7-day-infected mice do not proliferate in vitro in response to ConA stimulation, do not produce IL-2 but display high affinity IL-2 receptors on their membrane. The non-coordinated regulation of these genes suggested that other cytokine-encoding genes may also be affected in their regulation. We have thus analyzed the expression of the genes encoding different cytokines transcribed during spleen cell activation by ConA. The genes encoding T lymphocyte-derived cytokines can be classified in three groups: the genes expressed similarly by normal and LCMV-cells (the p55 and the p75 chains of the IL-2 receptor [1]), the genes under expressed in LCMV-cells (IL-2, IL-3, IL-4 and IL-5) and the genes over expressed by these cells (GM-CSF and IFN-gamma). These results show that the viral infection has provoked a profound alteration of the overall regulation of the genetic program that follows T lymphocyte activation. Since T cell activation depends strictly on accessory cell-derived cytokines, we measured the level of transcription of IL-1, IL-6 and TNF-alpha; and our data show that the expression of these genes is equivalent in normal cells and in cells from LCMV-infected mice.