In vivo inhibition by intact mouse serum of the activity of the flavivirus-induced T-suppressors of autoreactive T-lymphocytes.

In the serum of healthy mice a factor was found inhibiting the in vivo effect of T-suppressors of autoreactive T-lymphocytes (TSart1) induced in mice by tick-borne encephalitis (TBE) virus, Langat virus, dengue virus type 2 (D2) and attenuated strain 17D of yellow fever virus. Activity of the serum factor (s) was demonstrated providing that the TSart1 had H-2 antigens completely or partially identical with the H-2 antigens of serum donors. The activity was not connected with destruction of TSart1. The factor (s) did not inhibit the in vivo activity of TBE virus-induced T-suppressors directed to the effectors of graft versus host reaction (GVHR) in allogeneic mice. These suppressors differed from TSart1 in their distribution in the organs of immune system. As suggested, the serum factor (s) inhibiting TSart1 may be involved in pathogenesis of virus infections and in regulation of virus-induced autoimmune processes.