Genetic diversity in the env V1-V2 region of proviral quasispecies from long-term controller MHC-typed cynomolgus macaques infected with SHIVSF162P4cy

Intra-host evolution of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) has been shown by viral RNA analysis in subjects who naturally suppress plasma viremia to low levels, known as controllers. However, little is known about the variability of proviral DNA and the inter-relationships among contained systemic viremia, rate of reservoir reseeding and specific major histocompatibility complex (MHC) genotypes, in controllers. Here, we analysed the proviral DNA quasispecies of the env V1-V2 region, in PBMCs and in anatomical compartments of 13 long-term controller monkeys after 3.2 years of infection with simian/human immunodeficiency virus (SHIV)SF162P4cy. A considerable variation in the genetic diversity of proviral quasispecies was present among animals. Seven monkeys exhibited env V1-V2 proviral populations composed of both clusters of identical ancestral sequences and new variants, whereas the other six monkeys displayed relatively high env V1-V2 genetic diversity with a large proportion of diverse novel sequences. Our results demonstrate that in SHIVSF162P4cy-infected monkeys there exists a disparate pattern of intra-host viral diversity and that reseeding of the proviral reservoir occurs in some animals. Moreover, even though no particular association has been observed between MHC haplotypes and the long-term control of infection, a remarkably similar pattern of intra-host viral diversity and divergence was found within animals carrying the M3 haplotype. This suggests that in animals bearing the same MHC haplotype and infected with the same virus, viral diversity follows a similar pattern with similar outcomes and control of infection

Infection of a simian B cell line by human and simian immunodeficiency viruses

It is well known that HIV-1 does not establish infection in nonhuman primates, nor in cell lines derived from them, due to the existence of saturable resistance factors. In this study, we show that an in vitro established Macaca fascicularis-derived CD4(-) B cell line (F6) can be productively infected by the laboratory-adapted T-tropic HXBc2/HIV-1 strain at low multiplicity of infection, apparently because it does not express the restriction factor that has been detected in other simian cell lines. Moreover, efficient entry into F6 cells was obtained with pseudotyped recombinant HIV-1 viruses containing the laboratory-adapted T-tropic (HXBc2) or the dual-tropic (89.6) envelope glycoproteins, whereas entry of virus containing the envelope glycoproteins of the M-tropic Ba-L strain was less efficient. Virus containing primary T-tropic (Eli) envelope glycoproteins did not infect F6 cells. Furthermore, although CCR5 was not present on the cell surface and gpr15 and strl33 mRNAs were not expressed in the cells, a high level of infection of F6 cells by the M-tropic simian immunodeficiency virus SIVmac316 was observed. In contrast, F6 cells were poorly infected by T-tropic SIVmac239. Given the unique properties of the F6 cell line, i.e., that it is of simian origin yet is able to be infected by HIV-1 in a CD4-independent manner, F6 cells represent a useful model for studying cellular factors mediating resistance or permissivity to HIV-1 infection and may help to evaluate HIV-1 and SIV cell tropism

Effect of MHC haplotype on immune response upon experimental SHIVSF162P4cy infection of Mauritian cynomolgus macaques.

Little is known about the effects of Major Histocompatibility Complex (MHC) haplotypes on immunity to primate lentiviruses involving both acquired and innate immune responses. We present statistical evidence of the influence of MHC polymorphism on antiviral immunity of Mauritian cynomolgus macaques (MCM) following simian/human immunodeficiency virus SHIVSF162P4cy infection, involving the production of pro- and anti-inflammatory cytokines and α-defensins, which may modulate acquired immune responses. During the acute phase of infection, IL-10 correlated positively with viral load and negatively with CD4+T cell counts. Furthermore, α-defensins production was directly correlated with plasma viral RNA, particularly at peak of viral load. When the effects of the MHC were analyzed, a significant association between lower anti-Env binding and neutralizing antibody levels with class IB M4 haplotype and with class IA, IB M4 haplotype, respectively, was observed in the post-acute phase. Lower antibody responses may have resulted into a poor control of infection thus explaining the previously reported lower CD4 T cell counts in these monkeys. Class II M3 haplotype displayed significantly lower acute and post-acute IL-10 levels. In addition, significantly lower levels of α-defensins were detected in class IA M3 haplotype monkeys than in non-M3 macaques, in the post-acute phase of infection. These data indicate that the MHC could contribute to the delicate balance of pro-inflammatory mechanisms, particularly with regard to the association between IL-10 and α-defensins in lentivirus infection. Our results show that host genetic background, virological and immunological parameters should be considered for the design and interpretation of HIV-1 vaccine efficacy studies

Regression analyses between immunological and virological parameters in infected monkeys during the acute phase of SHIV_SF162P4cy infection.

<p>A significant relationship was detected between: A) IL-10 production and plasma viral load (p = 0.0023); B) α-defensins production and viral RNA (p = 0.0286); C) IFNγ and IL-10 production (p<0.0001). D) AUC: significant relationship between viral load and α-defensins (p = 0.0002).</p

Plasma α-defensin, IL-10 and IFN-γ levels with respect to the pre-infection values in naïve (n = 11) and adjuvant treated monkeys (n = 10) inoculated with SHIV_SF162P4cy.

<p>No significant differences were observed between naive and adjuvant treated monkeys during the observation period. Mean values with standard deviations are connected by dotted lines.</p

Frequency of MHC class IA, class IB and class II and recombinant haplotypes in animals included in the study.

<p>Animals carrying specific Mhc class I haplotypes. MHC class IA: M1 = 7, M2 = 5, M3 = 9, M4 = 6, M5 = 1, M6 = 2, M7 = 4, rec = 6; frequency of MHC class IB: M1 = 9, M2 = 5, M3 = 11, M4 = 7, M5 = 1, M6 = 3, M7 = 4, rec = 1; frequency of MHC class II: M1 = 9, M2 = 4, M3 = 13, M4 = 6, M5 = 1, M6 = 4, M7 = 3, rec = 2 <i>rec</i> recombinant haplotype.</p

Effects of MHC class I<i>A</i> and I<i>B</i> haplotypes on IgG anti-Env antibodies and neutralizing Ab following infection with SHIV_SF162P4cy.

<p>Mean values with standard error are depicted for all animals positive or negative for the indicated haplotype: M4 (n = 6) non-M4 (n = 15) class I<i>A</i>; M4 (n = 7), non-M4 (n = 14) class I<i>B</i>.</p