In vitro studies on cell-mediated immune response to tick-borne encephalitis virus: findings in convalescents and human subclinical infections.

Peripheral blood leukocytes from tick-borne encephalitis (TBE) convelescents (manifest and inapparent forms) working with TBE virus-containing material and from individuals without specific serum virus neutralizing antibodies (VNA) were studied in capillary tube leukocyte migration experiments. Partially purified TBE virus preparations were used as antigen. Under standardized conditions a strong inhibitory reaction was observed in convalescents with significantly higher values in persons recovered from an abortive form of infection only. These results differed markedly from values recorded in persons without specific VNA. Significance of correlation between humoral VNA titres and the intensity of the cell-mediated component of the immune response (CM IR), as indicated by leukocyte migration inhibition (LMI) values, was less than P equals 0.25.