Identification of a New Subgroup of SIVagm in Tantalus Monkeys

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Caribbean-born African green monkeys (AGMs) were classified as .). CD4 ؉ T-cell counts in the blood showed a transient depletion at the peak of VL, and then returned to near preinfection values by day 28 p.i. and remained relatively stable during the chronic infection. Preservation of CD4 T cells was also found in lymph nodes (LNs) of chronic SIVagm.sab-infected Caribbean AGMs. No activation of CD4؉ T cells was detected in the periphery in SIV-infected Caribbean AGMs. These virological and immunological profiles from peripheral blood and LNs were identical to those previously reported in African-born AGMs infected with the same viral strain (SIVagm.sab92018). Due to these similarities, we conclude that Caribbean AGMs are a useful alternative to AGMs of African origin as a model for the study of SIV infection in natural African hosts.

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confidence: 99%

Simian Immunodeficiency Virus SIVagm.sab Infection of Caribbean African Green Monkeys: a New Model for the Study of SIV Pathogenesis in Natural Hosts

Pandrea

Apetrei

Dufour

et al. 2006

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221

“…Each of the four AGM species, i.e., vervet (Chlorocebus pygerythrus), grivet (C. aethiops), sabaeus (C. sabaeus), and tantalus (C. tantalus), carries its species-specific SIVagm subtype, referred to as SIVagm.ver, SIVagm.gri, SIVagm.sab, and SIVagm.tan, respectively (1,26,29,49). SIVagm infections in AGMs were repeatedly reported to be nonpathogenic (6,9,18,22,23), similar to what has been reported for other SIV infections in natural hosts (32).…”

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confidence: 99%

Impact of Viral Factors on Very Early In Vivo Replication Profiles in Simian Immunodeficiency Virus SIVagm-Infected African Green Monkeys

Pandrea

Kornfeld

Ploquin

et al. 2005

To better understand which factors govern the levels of viral loads in early lentiviral infections of primates, we developed a model that allows distinguishing between the influences of host and viral factors on viremia. Herein we report that two species of African green monkeys (Chlorocebus sabaeus and C. pygerythrus) infected with their respective wild-type simian immunodeficiency virus SIVagm viruses (SIVagm.sab92018 and SIVagm. ver644) consistently showed reproducible differences in viremia during primary infection but not at later stages of infection. Cross-infections of SIVagm.sab92018 and SIVagm.ver644 into, respectively, C. pygerythrus and C. sabaeus revealed that the dynamics of viral replication during primary infection were dependent on the viral strain used for the infection but not on the host. Hence, the kinetics of SIVagm.sab92018 and SIVagm.ver644 were similar in both sabaeus and vervet animals, indicating that the difference in viremia levels between the two groups during the early phase of infection was not associated with the host. Coreceptor usage for these two strains showed a larger coreceptor repertoire for SIVagm.sab92018, which is able to efficiently use CXCR4 in addition to CCR5, than for SIVagm.ver644, which showed a classical CCR5 coreceptor usage pattern. These differences could not be explained by different charges of the V3 loop for SIVagm.sab92018 and for SIVagm. ver644. In conclusion, our study showed that the extent of virus replication during the primary infection is primarily dependent on viral determinants.

“…For example, SIV lineages have been identified that are specific for SM (SIVsm) and AGM (SIVagm). The initial identification of distinct subtypes of SIVagm (SIVagmGri, -Ver, -Sab, and -Tan) specific to the four geographically separated AGM species, namely, grivet (7), vervet (1,22,45), sabaeus (21), and tantalus (18,29) monkeys (Chlorocebus aethiops, C. pygerythrus, C. sabaeus, and C. tantalus, respectively), suggested that these viruses have coevolved with their primate host species over a long period of time (3,29). Despite high seroprevalence rates in feral and captive populations, natural infections of African primates with their own SIV strains are not generally associated with immunodeficiency (16).…”

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confidence: 99%

Comparison of Simian Immunodeficiency Virus SIVagmVer Replication and CD4 ⁺ T-Cell Dynamics in Vervet and Sabaeus African Green Monkeys

Goldstein

Brown

Ourmanov

et al. 2006

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The simian immunodeficiency viruses (SIV) naturally infect a wide range of African primates, includingAfrican green monkeys (AGM). Despite moderate to high levels of plasma viremia in naturally infected AGM, infection is not associated with immunodeficiency. We recently reported that SIVagmVer90 isolated from a naturally infected vervet AGM induced AIDS following experimental inoculation of pigtailed macaques. The goal of the present study was to evaluate the replication of this isolate in two species of AGM, sabaeus monkeys (Chlorocebus sabaeus) and vervets (C. pygerythrus). Inoculation of sabaeus AGM with SIVagmVer90 resulted in low and variable primary and set-point viremia (<10 2 to 10 4 copies/ml). In contrast, inoculation of vervet AGM with either SIVagmVer90 or blood from a naturally infected vervet (Ver1) resulted in high primary viremia and moderate plateau levels, similar to the range seen in naturally infected vervets from this cohort. CD4 ؉ T cells remained stable throughout infection, even in AGM with persistent high viremia. Despite the lack of measurable lymphadenopathy, infection was associated with an increased number of Ki-67 ؉ T cells in lymph node biopsies, consistent with an early antiviral immune response. The preferential replication of SIVagmVer in vervet versus sabaeus AGM shows that it is critical to match AGM species and SIV strains for experimental models of natural SIV infection.