Along with its in vitro properties of being a potent activator of the immune system and stimulating HIV gene expression, M. penetrans holds a position as the best possible candidate for a cofactor of HIV in the development of AIDS [6]. M. penetrans has the ability to induce an in vitro proliferative response of CD4 and CD8 T cells with expression of some activation markers such as CD69, HLA-DR, and CD 25 [23]. Here, CD4 is linked to AIDS.