CD4 and infection: Because FIV predominately targets CD4+ T-lymphocytes for infection in domestic cats [1,2,3,4,6,8], it is possible that immunosuppressive doses of prednisolone and CsA could broadly reduce lymphocyte proliferation and activation in FIV-infected cats, thereby decreasing the number of target cells for FIV infection and as a result, reduce FIV viral and proviral loads in circulation.