Abstract
BackgroundAlthough pig-tailed macaques (Macaca nemestrina) have been used in AIDS research for years, less is known about the early immunopathogenic events in this species, as compared to rhesus macaques (Macaca mulatta). Similarly, the events in early infection are well-characterized for simian immunodeficiency viruses (SIV), but less so for chimeric simian-human immunodeficiency viruses (SHIV), although the latter have been widely used in HIV vaccine studies. Here, we report the consequences of intrarectal infection with a CCR5-tropic clade C SHIV-1157ipd3N4 in pig-tailed macaques.ResultsPlasma and cell-associated virus was detectable in peripheral blood and intestinal tissues of all four pig-tailed macaques following intrarectal inoculation with SHIV-1157ipd3N4. We also observed a rapid and irreversible loss of CD4+ T cells at multiple mucosal sites, resulting in a marked decrease of CD4:CD8 T cell ratios 0.5–4 weeks after inoculation. This depletion targeted subsets of CD4+ T cells expressing the CCR5 coreceptor and having a CD28-CD95+ effector memory phenotype, consistent with the R5-tropism of SHIV-1157ipd3N4. All three animals that were studied beyond the acute phase seroconverted as early as week 4, with two developing cross-clade neutralizing antibody responses by week 24. These two animals also demonstrated persistent plasma viremia for >48 weeks. One of these animals developed AIDS, as shown by peripheral blood CD4+ T-cell depletion starting at 20 weeks post inoculation.ConclusionThese findings indicate that SHIV-1157ipd3N4-induced pathogenesis in pig-tailed macaques followed a similar course as SIV-infected rhesus macaques. Thus, R5 SHIV-C-infection of pig-tailed macaques could provide a useful and relevant model for AIDS vaccine and pathogenesis research.
Highlights
Pig-tailed macaques (Macaca nemestrina) have been used in AIDS research for years, less is known about the early immunopathogenic events in this species, as compared to rhesus macaques (Macaca mulatta)
These findings suggest that the efforts to develop an AIDS vaccine may be well served by examining a diverse range of antiviral responses and disease susceptibilities in different animal models
We evaluated the infectivity and pathogenicity of simian-human immunodeficiency viruses (SHIV)-1157ipd3N4 in pig-tailed macaques to determine its potential role as an alternative challenge model in future AIDS vaccine studies
Summary
Pig-tailed macaques (Macaca nemestrina) have been used in AIDS research for years, less is known about the early immunopathogenic events in this species, as compared to rhesus macaques (Macaca mulatta). In a comparative study of Asian macaques infected intravenously with simian immunodeficiency virus (SIV) or simian-human immunodeficiency virus (SHIV) strains, SIVmac251 or SHIV89.6P, Reimann et al found lower plasma viral loads, higher levels of peripheral CD4+ T cells, and higher survival rates in cynomolgus and Chinese rhesus, compared to infected Indian rhesus [12]. Consistent with the Reimann et al report above, Ling et al showed a differential response to lentiviral infection at the subspecies level Compared to their Indian counterparts, Chinese rhesus infected with SIVmac239 had lower plasma viral loads in acute infection, maintained lower setpoint plasma viremia, and experienced less severe depletion of intestinal CD4+ effector cells, all of which resulted in better clinical outcomes [14]. Burdo et al found that serial passage of SIVmac128 in Chinese rhesus resulted in increased steady-state viral loads as compared to animals infected with the virus derived from Indian monkeys, implying that host adaptation plays an important role in viral fitness and pathogenicity [15]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
