Yj. Hernandez et al., Latent adeno-associated virus infection elicits humoral but not cell-mediated immune responses in a nonhuman primate model, J VIROLOGY, 73(10), 1999, pp. 8549-8558
Latent infection with wild-type (wt) adeno-associated virus (AAV) was studi
ed in rhesus macaques, a species that is a natural host for AAV and that ha
s some homology to humans with respect to the preferred locus for wt AAV in
tegration. Each of eight animals was infected with an inoculum of 10(10) IU
of wt AAV, administered by either the intranasal, intramuscular, or intrav
enous route. Two additional animals were infected intranasally with wt AAV
and a helper adenovirus (Ad), while one additional animal was inoculated wi
th saline intranasally as a control. There were no detectable clinical or h
istopathologic responses to wt AAV administration. Molecular analyses, incl
uding Southern blot, PCR, and fluorescence in situ hybridization, were perf
ormed 21 days after infection. These studies indicated that AAV DNA sequenc
es persisted at the sites of administration, albeit at low copy number, and
in peripheral blood mononuclear cells. Site-specific integration into the
AAVS1-like locus was observed in a subset of animals. All animals, except t
hose infected by the intranasal route with wt AAV alone, developed a humora
l immune response to wt AAV capsid proteins, as evidenced by a greater than
or equal to fourfold rise in anti-AAV neutralizing titers. However, only a
nimals infected with both wt AAV and Ad developed cell-mediated immune resp
onses to AAV capsid proteins. These findings provide some insights into the
nature of anti-AAV immune responses that may be useful in interpreting res
ults of future AAV-based gene transfer studies.