Role of virus-induced autoreactive T-lymphocytes, T-suppressors and the serum factor regulating their activity in the pathogenesis of experimental infection caused by the Langat virus in mice

The precursors of autoreactive T-lymphocytes (PARTL) have been detected in the spleen of mice infected with Langat virus. When introduced into syngeneic recipients, PARTL differentiate in their lymph nodes into autoreactive T-lymphocytes (ARTL) causing a fatal autoimmune disease in the syngeneic recipients in vivo and capable of destroying syngeneic cell cultures in vitro. In the thymus of mice infected with Langat virus T-suppressors (TS) inhibiting the differentiation of PARTL into ARTL have been detected. The serum of intact mice has been shown to contain the serum blocking factor (SBF) which suppresses the differentiation of PARTL and the activity of TS from donors having common H-2 haplotypes of the gene complex with serum donors. In the course of viral infection the decrease of SBF activity and, simultaneously, the activation of PARTL and TS occur. The activation of PARTL and TS in infected mice may be suppressed by the injection of the serum of intact donors identical in H-2 haplotypes. The injection of ARTL induced by Langat virus into syngeneic recipients infected with this virus provokes the transformation of asymptomatic infection into acute infection, while TS and SBF blocking the differentiation of PARTL protect the animals from death.