Arch Virol (1998) 143: 513–521
Mapping the genetic determinants of human immunodeﬁciency
virus type 2 for cell tropism and replication efﬁciency
M. Kawamura, R. Shimano, T. Ogasawara, R. Inubushi, K. Amano,
H. Akari, and A. Adachi
Department of Virology, School of Medicine, University of Tokushima,
Accepted October 15, 1997
Summary. Two distinct infectious molecular clones of human immunodeﬁciency
type 2 (HIV-2) were analyzed for their biological properties in six cell lines.
Fourteen chimeric and ten mutant viruses were constructed from these two viral
genomes to localize the genetic determinants responsible for the phenotypes.
Growth property of the viruses in the cell lines, together with the biochemical
data, showed that a major determinant for the viral tropism resides in the env
gene. In addition, in some cell lines, the accessory genes vif and nef affected the
efﬁciencyof virus replication. Thus, like HIV-1, mutations in the auxiliary and env
genes of HIV-2 contributed much to the differences in virological characteristics.
Strains of human immunodeﬁciency virus type 1 (HIV-1) display a high degree of
biological heterogeneity which may be linked to certain clinical manifestations
of AIDS. They vary in their cellular host range or tropism, kinetics of replication,
cytopathology, and so on . Some of these biological properties in vitro corre-
lates with virus pathogenicity in vivo. HIV-1 isolates recovered from patients with
advanced disease are more cytopathic, replicate with faster kinetics and exhibit
a wider cellular host range than isolates obtained from the same individual in a
previously healthy state [3, 20].
HIV-2 and simian immunodeﬁciency virus isolated from macaques (SIVmac)
represent a distinct and unique class of various primate immunodeﬁciency viruses
. While HIV-1 can not grow and cause AIDS in monkeys routinely used, viruses
of this group replicate in the animals wellandefﬁciently induce the disease [7, 11].
Molecular clones, essential for molecular genetic study, of this virus subgroup
have been available [7, 11]. Therefore, many of the important ﬁndings on in
vivo properties of HIV/SIV have come from experimental infections of macaque