Inhibition of lymphocyte mitogenesis in mice infected with Newcastle disease virus: viral interference with the interleukin system.

Spleen cells from mice infected with Newcastle disease virus (NDV) fail to proliferate when cultured with allogeneic cells or with concanavalin A (Con A). This failure is not due to impairment of interleukin-1 (IL-1) production or to a lack of accessory cell function as stimulator cells from NDV-infected mice induce DNA synthesis in the mixed lymphocyte reaction. However, spleen cells from NDV-infected mice fail to produce detectable amounts of interleukin-2 (IL-2) when stimulated with mitogenic doses of Con A and do not respond to exogenous IL-2-containing preparations. Furthermore, absorption experiments suggest that cells from NDV-infected mice fail to bind appreciable amounts of exogenous IL-2. All these events seem to be infection-dependent, as cells from mice injected with ultraviolet-inactivated NDV (UV-NDV) behave normally.