In contrast to HIV-1, no studies have been published on the genetic an
d functional analysis of the envelope gene of primary NSI isolates of
HIV-2. However several studies on HIV-1 have shown that NSI strains ar
e the most frequently transmitted strains and probably the most import
ant strains in the pathogenesis of HIV infection. Furthermore, it has
been shown that the genetic and biological characteristics of primary
isolates of HIV-1 differ widely from those of T-cell-line adapted isol
ates. Two different polymerase chain reaction (PCR) methods, nested-po
lymerase chain reaction and overlapp-extension amplification, were use
d to amplify the envelope genes from a primary non-syncytium-inducing
HIV-2 isolate, HIV-2(ALI), and from the T-cell line adapted syncytium-
inducing isolate, HIV-2(ROD). These methods could amplify the complete
envelope gene from both viruses. Nested-polymerase chain reaction met
hod was highly sensitive, enabling the amplification of one proviral c
opy of HIV-2(ALI) in 10000 peripheral blood mononuclear cells. The use
of the methods described herein may help to expand our knowledge on t
he genetic diversity of HIV-2 as well as on the structure and function
of the envelope glycoproteins of primary HIV-2 isolates. (C) 1996 Aca
demic Press Limited