P. Trivedi et al., SELECTIVE AMPLIFICATION OF SIMIAN IMMUNODEFICIENCY VIRUS GENOTYPES AFTER INTRARECTAL INOCULATION OF RHESUS-MONKEYS, Journal of virology, 68(11), 1994, pp. 7649-7653
Animal models for sexual transmission of human immunodeficiency virus
can define the influences of virus type, dose, and route of inoculatio
n on infection and clinical outcome. We used an uncloned simian immuno
deficiency virus stock (SIVmac) to inoculate cells in vitro and to ino
culate rhesus monkeys by intravenous and intrarectal routes. The distr
ibution of virus genotypes present in each of these infection examples
was characterized by DNA sequence analysis of viral long terminal rep
eats (LTRs). Our analysis of LTR sequences from in vitro and in vivo i
nfections revealed three main genotypes: one genotype was observed onl
y for in vitro infection, and two other genotypes were recovered only
from infected animals. By comparing animals inoculated with high intra
rectal doses of SIVmac and those inoculated with low doses, we demonst
rated that unique subsets of the stock were selected after intrarectal
infection. Our findings indicate that minor genotypes present in the
stock cross the rectal mucosa and are amplified selectively to become
prominent in peripheral blood mononuclear cells from acutely infected
animals. Studies with a molecular recombinant of SIV and human immunod
eficiency virus type 1 sequences, SHIV, showed that viral LTR sequence
s do not undergo especially rapid sequence variation or rearrangement
after intrarectal inoculation. The mucosal barrier exerts a significan
t influence on infection and disease progression by reducing the effic
iency of SIVmac infection and by permitting distinct, pathogenic genot
ypes to become established in the host.