Semliki Forest virus vectors expressing the H and HN genes of measles and mumps viruses reduce immunity induced by the envelope protein genes of rubella virus.

A Semliki Forest virus (SFV) recombinant particle vaccine vector was constructed expressing the viral E1 and E2 envelope proteins of the RA27/3 vaccine strain of rubella virus. This vector induced high titres of antibody after intramuscular administration to Balb/C mice, both following initial vaccination and a boost 4 weeks later. This occurred for antibody as measured by ELISA and as measured by a latex agglutination test. However, co-administration of similar particles expressing the measles virus H protein and the mumps virus HN protein with the rubella protein expressing vector resulted in reduction of the anti-rubella immune response.