Robust HIV type 2 cellular immune response measured by a modified anthrax toxin-based enzyme-linked immunospot assay

Evaluation of immune mechanisms responsible for control of viral replicatio n is critical to understanding HIV-2 attenuated biological characteristics in pathogenesis and transmission. Evaluation of the cellular immune respons e is often based on labor-intensive techniques that limit the scope of most studies performed. A simple and rapid anthrax toxin-based ELISPOT method t o assess HIV-2 cellular immune response was developed. The modified anthrax toxin-based antigen presentation process performed better than a recombina nt vaccinia system and the ELISPOT method significantly enhanced the ease a nd simplicity of the assay. Using this method, a robust HIV-2 cellular immu ne response directed toward the p26 core protein was exhibited in 21 of 24 (87.5%) infected women, and all 8 seronegative subjects were negative in bo th assays. Cellular immune responses were associated with low HIV-2 viral l oad. This simple and rapid modified anthrax toxin-based ELISPOT method allo wed us to demonstrate, strong cellular immune responses that may be critica l determinants in the HIV-2 attenuated phenotype.