Preliminary evidence for cell-mediated immunity in cross-protection among group A arboviruses

Unfractionated and T cell-enriched populations from spleens of mice immunized with Sinbdis virus confer cross-protection against Semliki forest virus challenge in recipient mice. Both Group A viruses are serologically related, but not by tests for cross-neutralizing antibody. The protection in mice persisted for three consecutive cell passages in uninfected mice. The results suggest that cell-mediated immunity accounts for cross-protection.