Human immunodeficiency virus isolated from a serum sample collected in 1976 in Central Africa.

Abstract

The screening of 454 serum samples from northern Zaire for antibodies to the Ebola virus has revealed the earliest human immunodeficiency virus (HIV) isolated identified to date. The serum tested in this study were collected in 1976; previously an HIV isolate collected in 1983 was believed to be the 1st such case. 5 (1%) of the 454 serum samples from 1976 were positive by ELISA and Western blot. 1 of the positive samples was obtained from a 26-year-old unmarried woman who died in 1978 of an illness suggestive of acquired immunodeficiency syndrome (AIDS). Her symptoms included prolonged fever substantial weight loss headaches oral lacerations dysphagia and persistent cough with hemoptysis. The women was from a small village in Northwest Zaire but had lived in Kinshasa in 1971-1975. The isolates obtained in this series were compared to HIV isolates from other populations in terms of viral proteins antigenic cross-reactivity and Southern hybridization. A unique pattern of reactivity was found for all 5 Zairian isolates. Homologous radioimmunoassay indicated that the major core proteins of Zairian HIV (CDC451) and HZ 321 were identical. All 5 isolates showed major bands at molecular bands of 18000 24000 and 41000. In addition the strains showed reactivity with the p65 polymerase gene product. The distinct nature of HZ 321 was further confirmed by the production of hybridization patterns different from human T-cell lymphotropic virus (HTLV-III). This study suggests that HIV was circulating in rural Zaire several years before its recognition in Kinshasa. The finding that HIV can be isolated from serum frozen initially at minus 70 C and later at minus 20 C should encourage additional analyses of serum samples collected in the 1970s in rural Africa.