FP85A

FP85A is a candidate vaccine developed for the prevention of tuberculosis (TB). It is a recombinant viral vector vaccine, specifically based on the fowlpox virus (FP9) engineered to express antigen 85A (Ag85A), a major immunodominant protein from Mycobacterium tuberculosis. The vaccine was designed to induce cellular immune responses against TB, particularly in individuals previously vaccinated with Bacillus Calmette-Guérin (BCG). In phase I clinical trials, FP85A was evaluated both alone and in combination with MVA85A (another Ag85A-expressing viral vector) as part of prime-boost regimens. While FP85A was well tolerated and induced anti-FP9 IgG antibodies, it did not significantly enhance Ag85A-specific cellular immunity in humans. There is evidence that pre-vaccination with FP85A may reduce the immunogenicity of subsequent MVA85A vaccination due to cross-reactive antibody responses[1][4][6].