Functional analysis of frequently expressed Chinese rhesus macaque MHC class I molecules Mamu-A1*02601 and Mamu-B*08301 reveals HLA-A2 and HLA-A3 supertypic specificities

The Simian immunodeficiency virus (SIV)-infected Indian rhesus macaque (Macaca mulatta) is the most established model of HIV infection and AIDS-related research, despite the potential that macaques of Chinese origin is a more relevant model. Ongoing efforts to further characterize the Chinese rhesus macaques?? major histocompatibility complex (MHC) for composition and function should facilitate greater utilization of the species. Previous studies have demonstrated that Chinese-origin M. mulatta (Mamu) class I alleles are more polymorphic than their Indian counterparts, perhaps inferring a model more representative of human MHC, human leukocyte antigen (HLA). Furthermore, the Chinese rhesus macaque class I allele Mamu-A1*02201, the most frequent allele thus far identified, has recently been characterized and shown to be an HLA-B7 supertype analog, the most frequent supertype in human populations. In this study, we have characterized two additional alleles expressed with high frequency in Chinese rhesus macaques, Mamu-A1*02601 and Mamu-B*08301. Upon the development of MHC?Cpeptide-binding assays and definition of their associated motifs, we reveal that these Mamu alleles share peptide-binding characteristics with the HLA-A2 and HLA-A3 supertypes, respectively, the next most frequent human supertypes after HLA-B7. These data suggest that Chinese rhesus macaques may indeed be a more representative model of HLA gene diversity and function as compared to the species of Indian origin and therefore a better model for investigating human immune responses.     

Frequency of the major histocompatibility complex Mamu-A*01 allele in a closed breeding colony of rhesus monkey (Macaca mulatta) from Brazil

Background  Rhesus monkeys are relevant models for human diseases. The simian immunodeficiency virus (SIV) infection is an useful macaque model for assessing human immunodeficiency virus (HIV) vaccine strategies. Susceptibility and resistance to viruses have been associated with particular major histocompatibility complex (MHC) molecules. Several epitopes in the HIV structural and non-structural protein restricted by distinct MHC class I haplotypes are important targets for human cytotoxic T lymphocytes, which mediate protection against SIVmac infection. Mamu-A*01 , for example, is a MHC class I molecule of rhesus monkeys that presents a peptide from SIV gag protein.
Methods  Our study determined the frequency of Mamu-A*01 in a closed colony of rhesus monkeys from Brazil by polymerase chain reaction.
Results  A high frequency of the allele was found in the study colony.
Conclusion  This colony provides a significant source of A*01 -positive animals to investigators.     

MHC class I alleles influence set-point viral load and survival time in simian immunodeficiency virus-infected rhesus monkeys

In HIV-infected humans and SIV-infected rhesus macaques, host genes influence viral containment and hence the duration of the disease-free latency period. Our knowledge of the rhesus monkey immunogenetics, however, is limited. In this study, we describe partial cDNA sequences of five newly discovered rhesus macaque (Mamu) class I alleles and PCR-based typing techniques for the novel and previously published Mhc class I alleles. Using 15 primer pairs for PCR-based typing and DNA sequence analysis, we identified at least 21 Mhc class I alleles in a cohort of 91 SIV-infected macaques. The results confirm the presence of multiple class I genes in rhesus macaques. Of these alleles, Mamu-A*01 was significantly associated with lower set-point viral load and prolonged survival time. Mamu-A*1303 was associated with longer survival and a "novel" Mhc class I allele with lower set-point viral load. The alleles are frequent in rhesus macaques of Indian origin (12-22%). In addition, survival probability of individual SIV-infected rhesus monkeys increased with their number of alleles considered to be associated with longer survival. The results contribute to improve the interpretation and quality of preclinical studies in rhesus monkeys.     

Unique peptide-binding motif for Mamu-B*037:01: an MHC class I allele common to Indian and Chinese rhesus macaques

Indian and Chinese rhesus macaques are often used in biomedical research. Genetic analyses of the major histocompatibility class I region have revealed that these macaques display a substantial level of polymorphism at Mamu-A and Mamu-B loci, which have been subject to duplication. Only a few Mamu class I allotypes are characterised for their peptide-binding motifs, although more information of this nature would contribute to a better interpretation of T cell-mediated immune responses. Here, we present the results of the characterisation of the functional properties of Mamu-B*037:01, an allotype commonly encountered in rhesus macaques of Indian and Chinese origin. Mamu-B*037:01 is seen to have a strong preference for acidic amino acids at the third residue, and for arginine, lysine, and tyrosine at the carboxyl terminus. This peptide-binding motif is not described in the human population.     

Initiation of antiretroviral therapy during chronic SIV infection leads to rapid reduction in viral loads and the level of T-cell immune response

In the present era of increasing resistance of human immunodeficiency virus (HIV) to antiviral drugs, exploration of adjunct therapies directed at immune responses in combination with antiretroviral drugs may be of value for the treatment of acquired immunodeficiency syndrome. In this study, we designed a model for immune therapy using SIVmac251 infection in rhesus macaques. We explored the outcomes of primary infection on viral loads and the resulting T-cell immune responses in primates. The SIV-infected rhesus macaque model exhibited features similar to those observed in HIV-1 infection of humans. Major histocompatibility complex (MHC) segregation with viral loads were found to associate with viral containment and hence the duration of the disease-free latency period. Thus a better understanding of the relative roles of MHC class I allele in control of viral replication may provide important information for prophylactic or therapeutic vaccine designs. Mamu-A01 is significantly associated with higher immune response and control of viral replication. This allele is frequent in rhesus macaques of Indian origin (22%). Interestingly, Mamu-B01 (26% animals) was associated with lower immune responses and higher viral loads. Another allele, A08 was also predominantly present in 37% of the animals in this study. We observed higher viral replication in individual SIV-infected rhesus monkeys that did not demonstrate strong cellular immune responses. The results are important for understanding SIV disease progression in different MHC Mamu alleles and also for improving the interpretation and quality of pre-clinical studies in rhesus monkeys.     

Peptide-binding motifs associated with MHC molecules common in Chinese rhesus macaques are analogous to those of human HLA supertypes and include HLA-B27-like alleles

Chinese rhesus macaques are of particular interest in simian immunodeficiency virus/human immunodeficiency virus (SIV/HIV) research as these animals have prolonged kinetics of disease progression to acquired immunodeficiency syndrome (AIDS), compared to their Indian counterparts, suggesting that they may be a better model for HIV. Nevertheless, the specific mechanism(s) accounting for these kinetics remains unclear. The study of major histocompatibility complex (MHC) molecules, including their MHC/peptide-binding motifs, provides valuable information for measuring cellular immune responses and deciphering outcomes of infection and vaccine efficacy. In this study, we have provided detailed characterization of six prevalent Chinese rhesus macaque MHC class I alleles, yielding a combined phenotypic frequency of 29 %. The peptide-binding specificity of two of these alleles, Mamu-A2*01:02 and Mamu-B*010:01, as well as the previously characterized allele Mamu-B*003:01 (and Indian rhesus Mamu-B*003:01), was found to be analogous to that of alleles in the HLA-B27 supertype family. Specific alleles in the HLA-B27 supertype family, including HLA-B*27:05, have been associated with long-term nonprogression to AIDS in humans. All six alleles characterized in the present study were found to have specificities analogous to HLA supertype alleles. These data contribute to the concept that Chinese rhesus macaque MHC immunogenetics is more similar to HLA than their Indian rhesus macaque counterparts and thereby warrants further studies to decipher the role of these alleles in the context of SIV infection.     

云南地区恒河猴MHC部分基因频率及多态性的分析

目的不同种群恒河猴（Macaca mulatta）主要组织相容性复合体（major histocompatibility complex,MHC）基因的差异性,很大程度上影响了用其作为动物模型的实验研究结果的稳定性、可靠性和可重复性。清晰了解云南地区恒河猴种群免疫遗传学背景对于运用该种群开展各项研究非常重要。恒河猴基因Mamu（Macaca mulatta）-A＊01就被公认与猴免疫缺陷病毒（SIV）的感染与延缓病程相联系。Mamu-Ⅱ类等位基因Mamu-DRB1＊0306、0309有研究表明也与SIV感染后的病程发展有关。方法针对目前研究热点的Mamu-A＊01基因及Ⅱ类Mamu-DRB1＊0306、0309基因,采用序列特异性引物-聚合酶链式反应方法（PCR-SSP）,对云南地区的140只恒河猴（其中92只来源于云南景东野外自然繁殖群、48只来源于本灵长类中心自繁群）进行检测。并对阳性样本用部分测序结合单链构象多态性分析（SSCP）的方法加以验证。结果Mamu-A＊01检测结果为阴性。Mamu-DRB1＊0306、0309基因频率分别为32%及45%。结论初步显示云南地区恒河猴种群Mamu-A＊01基因可能缺失或基因频率很低,但存在Mamu-DRB1＊0306、0309基因。初步证明SSCP方法代替大规模测序是可行的,为云南地区恒河猴在AIDS研究中的应用提供了部分依据,一定程度上填补了该种群的遗传背景资料。     

Mamu-B*08-positive macaques control simian immunodeficiency virus replication

Certain major histocompatibility complex (MHC) class I alleles are associated with the control of human immunodeficiency virus and simian immunodeficiency virus (SIV) replication. We have designed sequence-specific primers for detection of the rhesus macaque MHC class I allele Mamu-B*08 by PCR and screened a cohort of SIV-infected macaques for this allele. Analysis of 196 SIV(mac)239-infected Indian rhesus macaques revealed that Mamu-B*08 was significantly overrepresented in elite controllers; 38% of elite controllers were Mamu-B*08 positive compared to 3% of progressors (P = 0.00001). Mamu-B*08 was also associated with a 7.34-fold decrease in chronic phase viremia (P = 0.002). Mamu-B*08-positive macaques may, therefore, provide a good model to understand the correlates of MHC class I allele-associated immune protection and viral containment in human elite controllers.     

Preliminary observations of MHC class I A region polymorphism in three populations of Chinese-origin rhesus macaques

Rhesus macaques are an animal model for the study of a variety of human diseases. The Chinese rhesus macaques have been widely used in biomedical research in recent years. However, the polymorphism of major histocompatibility complex (MHC) class I A region among different local populations of Chinese rhesus macaques has never been investigated. In this study, we identified 46 Mamu-A alleles by cDNA cloning and sequencing on a cohort of 53 Chinese rhesus monkeys including Zhiming, Chuanxi, and Fujian populations, of which 5 were first reported in rhesus monkeys. The frequencies of alleles were identified for each population. The result suggests that the repertoire of allelic variants of MHC class I A region found in different populations of Chinese macaques is largely non-overlapping. The frequencies of alleles and the popular allele are also different for different populations. PCR-SSP experiment further confirms the different frequencies of two alleles, Mamu-A*026:01 and Mamu-A*022:01, in additional 99 Zhiming monkeys and 191 Chuanxi monkeys. Our findings have important practical implications in that the origin of the individuals and the genetic polymorphism of the monkeys need to be considered at the level of local populations for Chinese rhesus monkeys in biomedical research. Further immunogenetic work is needed to investigate the MHC polymorphism among different populations of Chinese rhesus macaques and to reveal the functional implication of such polymorphism and disease outcome correlations.     

CD8+ and CD20+ lymphocytes cooperate to control acute simian immunodeficiency virus/human immunodeficiency virus chimeric virus infections in rhesus monkeys: modulation by major histocompatibility complex genotype

We have previously described two isogenic molecularly cloned simian immunodeficiency virus/human immunodeficiency virus chimeric viruses (SHIVs) that differ from one another by 9 amino acids and direct distinct clinical outcomes in inoculated rhesus monkeys. SHIV(DH12R-Clone 7), like other highly pathogenic CXCR4-tropic SHIVs, induces rapid and complete depletions of CD4+ T lymphocytes and immunodeficiency in infected animals. In contrast, macaques inoculated with SHIV(DH12R-Clone 8) experience only partial and transient losses of CD4+ T cells, show prompt control of their viremia, and remain healthy for periods of time extending for up to 4 years. The contributions of CD8+ and CD20+ lymphocytes in suppressing the replication of the attenuated SHIV(DH12R-Clone 8) and maintaining a prolonged asymptomatic clinical course was assessed by treating animals with monoclonal antibodies that deplete each lymphocyte subset at the time of virus inoculation. The absence of either CD8+ or CD20+ cells during the SHIV(DH12R-Clone 8) acute infection resulted in the rapid, complete, and irreversible loss of CD4+ T cells; sustained high levels of postpeak plasma viremia; and symptomatic disease in Mamu-A*01-negative Indian rhesus monkeys. In Mamu-A*01-positive animals, however, the aggressive, highly pathogenic phenotype was observed only in macaques depleted of CD8+ cells; SHIV(DH12R-Clone 8) was effectively controlled in Mamu-A*01-positive monkeys in the absence of B lymphocytes. Taken together, these results indicate that both CD8+ and CD20+ B cells contribute to the control of primate lentiviral infection in Mamu-A*01-negative macaques. Furthermore, the major histocompatibility complex genotype of an infected animal, as exemplified by the Mamu-A*01 allele in this study, has the additional capacity to shift the balance of the composite immune response.     

Characterization of 47 MHC class I sequences in Filipino cynomolgus macaques

Cynomolgus macaques (Macaca fascicularis) provide increasingly common models for infectious disease research. Several geographically distinct populations of these macaques from Southeast Asia and the Indian Ocean island of Mauritius are available for pathogenesis studies. Though host genetics may profoundly impact results of such studies, similarities and differences between populations are often overlooked. In this study we identified 47 full-length MHC class I nucleotide sequences in 16 cynomolgus macaques of Filipino origin. The majority of MHC class I sequences characterized (39 of 47) were unique to this regional population. However, we discovered eight sequences with perfect identity and six sequences with close similarity to previously defined MHC class I sequences from other macaque populations. We identified two ancestral MHC haplotypes that appear to be shared between Filipino and Mauritian cynomolgus macaques, notably a Mafa-B haplotype that has previously been shown to protect Mauritian cynomolgus macaques against challenge with a simian/human immunodeficiency virus, SHIV_89.6P. We also identified a Filipino cynomolgus macaque MHC class I sequence for which the predicted protein sequence differs from Mamu-B*17 by a single amino acid. This is important because Mamu-B*17 is strongly associated with protection against simian immunodeficiency virus (SIV) challenge in Indian rhesus macaques. These findings have implications for the evolutionary history of Filipino cynomolgus macaques as well as for the use of this model in SIV/SHIV research protocols. Kevin J. Campbell and Ann M. Detmer contributed equally to this work.     

Attenuation of simian immunodeficiency virus SIVmac239 infection by prophylactic immunization with dna and recombinant adenoviral vaccine vectors expressing Gag

The prophylactic efficacy of DNA and replication-incompetent adenovirus serotype 5 (Ad5) vaccine vectors expressing simian immunodeficiency virus (SIV) Gag was examined in rhesus macaques using an SIVmac239 challenge. Cohorts of either Mamu-A*01(+) or Mamu-A*01(-) macaques were immunized with a DNA prime-Ad5 boost regimen; for comparison, a third cohort consisting of Mamu-A*01(+) monkeys was immunized using the Ad5 vector alone for both prime and boost. All animals, along with unvaccinated control cohorts of Mamu-A*01(+) and Mamu-A*01(-) macaques, were challenged intrarectally with SIVmac239. Viral loads were measured in both peripheral and lymphoid compartments. Only the DNA prime-Ad5-boosted Mamu-A*01(+) cohort exhibited a notable reduction in peak plasma viral load (sevenfold) as well as in early set-point viral burdens in both plasma and lymphoid tissues (10-fold) relative to those observed in the control monkeys sharing the same Mamu-A*01 allele. The degree of control in each animal correlated with the levels of Gag-specific immunity before virus challenge. However, virus control was short-lived, and indications of viral escape were evident as early as 6 months postinfection. The implications of these results in vaccine design and clinical testing are discussed.     

Comparison of the frequencies of major histocompatibility (MHC) class-II DQA1 and DQB1 alleles in Indian and Chinese rhesus macaques (Macaca mulatta)

The major histocompatibility complex (MHC) comprises related gene families, some of which are highly polymorphic, whose protein products mediate immune response. Rhesus macaques (Macaca mulatta) are a vital animal model for research in human diseases and are native to regions extending from Afghanistan in the west to the Eastern Plains of China and from Peking to the north, southward through islands of Southeast Asia. The distributions of MHC class-II Mamu DQA1 and Mamu DQB1 alleles in two groups of domestically bred rhesus macaques of Indian and Chinese origin and the Mamu DQA1 genotypes of a small number of Burmese rhesus macaques were compared. Major allelic differences were observed between the Indian and Chinese rhesus macaques, and gene diversity decreased from east to west. These and other intra-specific genetic differences among regional populations of rhesus macaques might influence the outcome of biomedical research in which they are used as subjects, and illustrate the importance of completely genetically characterizing subjects used as animal models in biomedical research.     

The most common Chinese rhesus macaque MHC class I molecule shares peptide binding repertoire with the HLA-B7 supertype

Of the two rhesus macaque subspecies used for AIDS studies, the Simian immunodeficiency virus-infected Indian rhesus macaque (Macaca mulatta) is the most established model of HIV infection, providing both insight into pathogenesis and a system for testing novel vaccines. Despite the Chinese rhesus macaque potentially being a more relevant model for AIDS outcomes than the Indian rhesus macaque, the Chinese-origin rhesus macaques have not been well-characterized for their major histocompatibility complex (MHC) composition and function, reducing their greater utilization. In this study, we characterized a total of 50 unique Chinese rhesus macaques from several varying origins for their entire MHC class I allele composition and identified a total of 58 unique complete MHC class I sequences. Only nine of the sequences had been associated with Indian rhesus macaques, and 28/58 (48.3%) of the sequences identified were novel. From all MHC alleles detected, we prioritized Mamu-A1*02201 for functional characterization based on its higher frequency of expression. Upon the development of MHC/peptide binding assays and definition of its associated motif, we revealed that this allele shares peptide binding characteristics with the HLA-B7 supertype, the most frequent supertype in human populations. These studies provide the first functional characterization of an MHC class I molecule in the context of Chinese rhesus macaques and the first instance of HLA-B7 analogy for rhesus macaques.     

Pathogenicity of simian-human immunodeficiency virus SHIV-89.6P and SIVmac is attenuated in cynomolgus macaques and associated with early T-lymphocyte responses

Because most studies of AIDS pathogenesis in nonhuman primates have been performed in Indian-origin rhesus macaques (Macaca mulatta), little is known about lentiviral pathogenicity and control of virus replication following infection of alternative macaque species. Here, we report the consequences of simian-human immunodeficiency virus SHIV-89.6P and SIVmac251 infection in cynomolgus (Macaca fascicularis) and rhesus macaques of Chinese origin. Compared to the pathogenicity of the same viruses in Indian rhesus macaques, both cynomolgus and Chinese rhesus macaques showed lower levels of plasma virus. By 9 to 10 months after infection, both viruses became undetectable in plasma more frequently in cynomolgus than in either Chinese or Indian rhesus macaques. Furthermore, after SHIV-89.6P infection, CD4+ T-cell numbers declined less and survival was longer in cynomolgus and Chinese rhesus macaques than in Indian rhesus macaques. This attenuated pathogenicity was associated with gamma interferon ELISPOT responses to Gag and Env that were generated earlier and of higher frequency in cynomolgus than in Indian rhesus macaques. Cynomolgus macaques also developed higher titer neutralizing antibodies against SHIV-89.6 at 10 and 20 weeks postinoculation than Indian rhesus macaques. These studies demonstrate that the pathogenicity of nonhuman primate lentiviruses varies markedly based on the species or geographic origin of the macaques infected and suggest that the cellular immune responses may contribute to the control of pathogenicity in cynomolgus macaques. While cynomolgus and Chinese rhesus macaques provide alternative animal models of lentiviral infection, the lower levels of viremia in cynomolgus macaques limit the usefulness of infection of this species for vaccine trials that utilize viral load as an experimental endpoint.     

Identification of MhcMafa-DRB Alleles in a Cohort of Cynomolgus Macaques of Vietnamese Origin

Cynomolgus macaques have been used widely to build a research model of infectious and chronic diseases, as well as in transplantation studies, where disease susceptibility and/or resistance are associated with the major histocompatibility complex (MHC). To better elucidate polymorphisms and genetic differences in the Mafa‐DRB locus, and facilitate the experimental use of cynomolgus macaques, we used pool screening combined with cloning and direct sequencing of polymerase chain reaction products to characterize MhcMafa‐DRB gene alleles in 153 Vietnamese cynomolgus macaques. We identified 30 Mafa‐DRB alleles belonging to 17 allelic lineages, including four novel sequences that had not been documented in earlier reports. The highest frequency allele was Mafa‐DRB*W27:04, which was present in 7 of 35 (20%) monkeys. The next most frequent alleles were Mafa‐DRB*3:07 and Mafa‐DRB*W7:01, which were detected in 5 of 35 (14.3%) and 4 of 35 (11.4%) of the monkeys, respectively. The high‐frequency alleles in this Vietnamese population may be high priority targets for additional characterization of immune functions. Only the DRB1*03 and DRB1*10 lineages were also present in humans, whereas the remaining alleles were monkey‐specific lineages. We found 25 variable sites by aligning the deduced amino acid sequences of 29 identified alleles. Evolutionary and population analyses based on these sequences showed that human, rhesus, and cynomolgus macaques share several Mhc‐DRB lineages and the shared polymorphisms in the DRB region may be attributable to the existence of interbreeding between rhesus and cynomolgus macaques. This information will promote the understanding of MHC diversity and polymorphism in cynomolgus macaques and increase the value of this species as a model for biomedical research. Am. J. Primatol. 74:958‐966, 2012. © 2012 Wiley Periodicals, Inc.     

Mamu-DQA1 allele and genotype frequencies in a randomly sampled breeding colony of rhesus macaques (Macaca mulatta)

We studied the allelic and genotypic distribution of the major histocompatibility class-II locus DQA1 observed in a random sample of Indian rhesus macaques (Macaca mulatta) from a major breeding facility in the United States. The DNA was isolated from whole blood samples collected between 1991 and 1994 from 65 Indian rhesus monkeys. Polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP), which involves use of specific amplification of DQA1 exon 2 and subsequent restriction digestion of the 242-base pair fragment, was used to genotype the animals for the 20 known macaque (Mamu)-DQA1 alleles. Frequencies for four alleles (DQA1*240x, *2502, *2503 and *0102) differed significantly from those reported in a smaller sample of rhesus macaques from the German Primate Center. The modest genetic survey of Mamu-DQA1 genotypes presented here will be particularly useful in designing epidemiologic studies that investigate associations between immunogenetic background and disease susceptibility in macaque models of human disease.     

Morphologic and immunophenotypic characteristics of malignant lymphomas in SIV-infected rhesus macaques

Eight cases of extranodal non-Hodgkin's lymphoma in simian immunodeficiency virus (SIV)-infected rhesus macaques, aged 4-9 years, were phenotypically and immunologically characterized, using the updated Kiel classification, in order to determine both the differences and the similarities between these types of lymphoma in immunodeficient rhesus macaques (Macaca mulatta) and man. The high-grade malignant tumors were of B-cell origin, with a predilection for extranodal growth in viscera and periorbital tissues. Immunophenotypical characterization showed that the monkey lymphomas were similar in many aspects to human immunodeficiency virus-associated lymphomas. The number of Ki67 positive cells varied from case to case and ranged from 50 to 90%. A serological screening for the simian equivalent of the Epstein-Barr virus (sEBV) by immunofluorescence assay revealed a prevalence of 92% of the sEBV antibodies in our cohort. The presence of Ebstein-Barr virus nuclear antigen (EBNA-2) could be demonstrated by immunohistochemistry in four out of eight cases. In situ hybridization revealed the presence of small EBV-encoded RNAs (EBER-1, EBER-2) in six of the eight cases. Further studies should define the precise role of herpesvirus infection for lymphomagenesis in SIV-induced immunodeficiency.     

Vectored Gag and Env but not Tat show efficacy against simian-human immunodeficiency virus 89.6P challenge in Mamu-A*01-negative rhesus monkeys

Simian-human immunodeficiency virus (SHIV) challenge studies in rhesus macaques were conducted to evaluate the efficacy of adenovirus-based vaccines in the context of different major histocompatibility complex class I genetic backgrounds and different vaccine compositions. Mamu-A*01 allele-negative rhesus monkeys were immunized with one of the following vaccine constructs: (i) replication-defective recombinant adenovirus type 5 (Ad5) expressing human immunodeficiency virus type 1 (HIV-1) Tat (Ad5/HIVTat); (ii) Ad5 vector expressing simian immunodeficiency virus (SIV) Gag (Ad5/SIVGag); (iii) Ad5 vector expressing the truncated HIV-1(jrfl) Env, gp140 (Ad5/gp140_jrfl); (iv) Ad5 vector expressing the SHIV-89.6P gp140 (Ad5/gp140_89.6P); or (v) the combination of Ad5/SIVGag and Ad5/gp140_jrfl. Following intravenous challenge with SHIV-89.6P, only those cohorts that received vaccines expressing Gag or Env exhibited an attenuation of the acute viremia and associated CD4-cell lymphopenia. While no prechallenge neutralizing antibody titers were detectable in either Ad5/gp140-vaccinated group, an accelerated neutralizing antibody response was observed in the Ad5/gp140_89.6P-vaccinated group upon viral challenge. The set-point viral loads in the Ad5/SIVGag- and Ad5/gp140_jrfl-vaccinated groups were associated with the overall strength of the induced cellular immune responses. To examine the contribution of Mamu-A*01 allele in vaccine efficacy against SHIV-89.6P challenge, Mamu-A*01-positive monkeys were immunized with Ad5/SIVGag. Vaccine-mediated protection was significantly more pronounced in the Mamu-A*01-positive monkeys than in Mamu-A*01-negative monkeys, suggesting the strong contributions of T-cell epitopes restricted by the Mamu-A*01 molecule. The implications of these results in the development of an HIV-1 vaccine will be discussed.     

A Large‐Scale SNP‐Based Genomic Admixture Analysis of the Captive Rhesus Macaque Colony at the California National Primate Research Center

Some breeding facilities in the United States have crossbred Chinese and Indian rhesus macaque (Macaca mulatta) founders either purposefully or inadvertently. Genetic variation that reflects geographic origins among research subjects has the potential to influence experimental outcomes. The use of animals from different geographic regions, their hybrids, and animals of varying degrees of kinship in an experiment can obscure treatment effects under study because high interanimal genetic variance can increase phenotypic variance among the research subjects. The intent of this study, based on a broad genomic analysis of 2,808 single nucleotide polymorphisms (SNPs), is to ensure that only animals estimated to be of pure Indian or Chinese ancestry, based on both demographic and genetic information, are used as sources of infants for derivation and expansion of the California National Primate Research Center's (CNPRC) super‐Specific Pathogen Free (SSPF) rhesus macaque colony. Studies of short tandem repeats (STRs) in Indian and Chinese rhesus macaques have reported that heterozygosity of STRs is higher in Chinese rhesus macaques than in Indian rhesus macaques. The present study shows that heterozygosity of SNPs is actually higher in Indian than in Chinese rhesus macaques and that the Chinese SSPF rhesus macaque colony is far less differentiated from their founders compared to the Indian‐origin animals. The results also reveal no evidence of recent gene flow from long‐tailed and pig‐tailed macaques into the source populations of the SSPF rhesus macaques. This study indicates that many of the long‐tailed macaques held in the CNPRC are closely related individuals. Most polymorphisms shared among the captive rhesus, long‐tailed, and pig‐tailed macaques likely predate the divergence among these groups. Am. J. Primatol. 74:747‐757, 2012. © 2012 Wiley Periodicals, Inc.