GENOTYPIC AND PHENOTYPIC CHARACTERIZATION OF HIV-1 IN PATIENTS WITH PRIMARY INFECTION

Better characterization of human immunodeficiency virus-type 1 (HIV-1) in patients with primary infection has important implications for the development of an acquired immunodeficiency syndrome (AIDS) vaccine b ecause vaccine strategies should target viral isolates with the proper ties of transmitted viruses. In five HIV-1 seroconverters, the viral p henotype was found to be uniformly macrophage-tropic and non-syncytium -inducing. Furthermore, the viruses were genotypically homogeneous wit hin each patient, but a common signature sequence was not discernible among transmitted viruses. In the two cases where the sexual partners were also studied, the sequences of the transmitted viruses matched be st with minor variants in the blood of the transmitters. There was als o a stronger pressure to conserve sequences in gp120 than in gp41, nef , and p17, suggesting that a selective mechanism is involved in transm ission.