[Change in host immune response to heterologous antigen when exposed to togavirus infection].

The influence of some members of the togavirus family (tick-borne encephalitis, dengue 2, Langat, Tahyna) and the vaccines used extensively for prophylaxis of tick-borne encephalitis and yellow fever on the immune response to a heterologous antigen was studied. The tick-borne encephalitis, Langat and dengue 2 viruses as well as the tick-borne encephalitis and yellow fever vaccines were found to alter the immune response of the recipient to subsequent administration of sheep erythrocytes. Some togaviruses (tick-borne encephalitis, Langat, yellow fever, dengue 2) stimulate formation of specific hemolysin-synthesizing cells, while others (Tahyna, dengue 2) under certain conditions may inhibit heterologous immune response. The nature of the influence depends upon genetically determined factors in the recipient, however, the conditions favouring the adjuvant or immunodepressive effect of one virus are not identical to those for another.