Cross-Reactivity with SIVmac in East African HIV-1-Positive Sera: Evidence against Double Infection with HIV-1 and a SIVmac/HIV-2-like Virus

Abstract

IgG antibodies reactive with simian immunodeficiency virus isolated from a rhesus monkey suffering from simian acquired immunodeficiency syndrome (SIVmac, strain 239, a virus which is very closely related to human immunodeficiency virus type 2-HIV-2) were found in 18 of 120 Swedish and 8 of 11 east African confirmed HIV-1 antibody positive (HIV-1 ab + ) sera, both by enzyme immunoassay and electrophoretic immunoblotting (p = 1 × 10 ⁶). In electrophoretic immunoblotting most of the cross-reactivity of SlVmac-reactive sera occurred on p27, the major gag protein of SIVmac. The possibility that SIVmac antibody reactivity could be due to double infection with HIV-1 and a SIVmac-related virus was eliminated by the results of absorptions between sera of Swedish and west and east African origin and viral antigens (SIVmac and North American or African/Haitian strains of HIV-1) coupled to agarose beads. HIV-2 ab+ and SIVmac reactive west African sera recognized SIVmac epitopes unrelated to HIV-1, whereas HIV-1 ab + , SIVmac reactive east African, and Swedish sera recognized SIVmac epitopes cross-reactive with epitopes present in both African and North American HIV-1 strains. No unique SIVmac-reactive African HIV-1 epitopes could thus be defined. Neither did absorption of Swedish and African HIV-1-positive sera with different HIV-1 strains (1 Haitian, 2 Zairian, and 1 North American) give evidence for unique epitopes.

MLV-Derived Retroviral Vectors Selective for CD4-Expressing Cells and Resistant to Neutralization by Sera from HIV-Infected Patients

“…However, the use of [MLV(HIV-1)] in HIV-seropositive individuals is hampered by the presence of antibodies directed against HIV-1 envelope proteins, which are expected to significantly reduce transduction efficiencies. Although neutralization of [MLV(SIVmac)] vector particles by HIV-1-specific antibodies was not studied by Indraccolo et al (1998), it is known from previous reports that sera from HIV-1-infected individuals cross-react with SIVmac (Blomberg et al, 1990). In contrast, the simian immunodeficiency virus (SIVagm) from African green monkeys (Chlorocebus pygerythrus) is only poorly neutralized by HIV-1-specific antibodies (Cichutek and Norley, 1993).…”