Chinese Rhesus Macaques Research Articles

Aikeqing decreases viral loads in SHIV89.6-infected Chinese rhesus macaques

BackgroundAikeqing (AKQ) has been shown in clinical studies to improve quality of life of HIV/AIDS patients, but anti-HIV activity has not been determined. The SHIV-infected macaque is an important animal model for testing antiviral drugs. This study aimed to determine the anti-HIV activity of AKQ in chronically SHIV89.6-infected Chinese rhesus macaques.MethodsNine Chinese rhesus macaques were inoculated intravenously with SHIV89.6 virus. At 11 weeks post-infection, the animals were arbitrarily divided into three groups: high-dose (AKQ 1.65 g/kg; n = 3), low-dose (AKQ 0.55 g/kg; n = 3), and control (water 1 mL/kg; n = 3). Treatment was administered by the intragastric gavage route once-daily for 8 weeks. Blood (5 mL) was collected biweekly. Viral loads were analyzed by real-time quantitative RT-PCR assays, and T cell counts were monitored by FACS analyses throughout the treatment.ResultsAKQ induced a persistent decline (P = 0.02) in plasma viral loads during treatment in the high-dose group compared with their baseline levels, and cessation of the therapy caused viral load rebound to the pretreatment levels. No significant difference (P = 0.06) was found in the plasma viral loads during treatment in the low-dose group. The CD4+ T cell counts and CD4/CD8 ratios remained at stable high levels during the treatment period.ConclusionAKQ reduced plasma viral loads in the SHIV89.6-infected Chinese rhesus macaque model.Electronic supplementary materialThe online version of this article (doi:10.1186/s13020-016-0105-x) contains supplementary material, which is available to authorized users.

SIV Infection Impairs the Central Nervous System in Chinese Rhesus Macaques.

The central nervous system (CNS) impairment is a consequence seen in SIV infection of rhesus macaques of Indian-origin, which is more common in infected macaques with rapid disease progression than in those with conventional disease progression. Here, we investigated the CNS damages in SIVmac239-infected Chinese rhesus macaques. We demonstrated that SIV infection of Chinese macaques could cause neuropathological impairments, which was evidenced by appearance of SIV-RNA positive cells, the infiltration of activated macrophages and abundant multinucleated giant cells (MNGCs) in the different regions of the brains. The animals with high viremia and short survival time (average of 16weeks, rapid progression, RP) had severer neuropathological changes than those with conventional progression (CP). As compared with the RP animals, CP macaques had lower viremia and much longer survival time (average of 154weeks). These findings indicate that SIVmac239 infection of Chinese rhesus macaque can be used as a suitable animal model and alternative resource for nueroAIDS research.

Potent neutralizing monoclonal antibodies against Ebola virus infection.

Ebola virus infections cause a deadly hemorrhagic disease for which no vaccines or therapeutics has received regulatory approval. Here we show isolation of three (Q206, Q314 and Q411) neutralizing monoclonal antibodies (mAbs) against the surface glycoprotein (GP) of Ebola virus identified in West Africa in 2014 through sequential immunization of Chinese rhesus macaques and antigen-specific single B cell sorting. These mAbs demonstrated potent neutralizing activities against both pseudo and live Ebola virus independent of complement. Biochemical, single particle EM, and mutagenesis analysis suggested Q206 and Q411 recognized novel epitopes in the head while Q314 targeted the glycan cap in the GP1 subunit. Q206 and Q411 appeared to influence GP binding to its receptor NPC1. Treatment with these mAbs provided partial but significant protection against disease in a mouse model of Ebola virus infection. These novel mAbs could serve as promising candidates for prophylactic and therapeutic interventions against Ebola virus infection.

Development of Broadly Neutralizing Antibodies and Their Mapping by Monomeric gp120 in Human Immunodeficiency Virus Type 1-Infected Humans and Simian-Human Immunodeficiency Virus SHIVSF162P3N-Infected Macaques.

To improve our understanding of the similarities and differences between neutralizing antibodies elicited by simian-human immunodeficiency virus (SHIV)-infected rhesus macaques and human immunodeficiency virus type 1 (HIV-1)-infected humans, we examined the plasma of 13 viremic macaques infected with SHIVSF162P3Nand 85 HIV-1-infected humans with known times of infection. We identified 5 macaques (38%) from 1 to 2 years postinfection (p.i.) with broadly neutralizing antibodies (bnAbs) against tier 2 HIV-1. In comparison, only 2 out of 42 (5%) human plasma samples collected in a similar time frame of 1 to 3 years p.i. exhibited comparable neutralizing breadths and potencies, with the number increasing to 7 out of 21 (30%) after 3 years p.i. Plasma mapping with monomeric gp120 identified only 2 out of 9 humans and 2 out of 4 macaques that contained gp120-reactive neutralizing antibodies, indicating distinct specificities in these plasma samples, with most of them recognizing the envelope trimer (including gp41) rather than the gp120 monomer. Indeed, a total of 20 gp120-directed monoclonal antibodies (MAbs) isolated from a human subject (AD358) and a Chinese rhesus macaque (GB40) displayed no or limited neutralizing activity against tier 2 strains. These isolated MAbs, mapped to the CD4-binding site, the V3 loop, the inner domain, and the C5 region of gp120, revealed genetic similarity between the human and macaque immunoglobulin genes used to encode some V3-directed MAbs. These results also support the use of envelope trimer probes for efficient isolation of HIV-1 bnAbs. HIV-1 vaccine research can benefit from understanding the development of broadly neutralizing antibodies (bnAbs) in rhesus macaques, commonly used to assess vaccine immunogenicity and efficacy. Here, we examined 85 HIV-1-infected humans and 13 SHIVSF162P3N-infected macaques for bnAbs and found that, similar to HIV-1-infected humans, bnAbs in SHIV-infected macaques are also rare, but their development might have been faster in some of the studied macaques. Plasma mapping with monomeric gp120 indicated that most bnAbs bind to the envelope trimer rather than the gp120 monomer. In support of this, none of the isolated gp120-reactive monoclonal antibodies (MAbs) displayed the neutralization breadth observed in the corresponding plasma. However, the MAb sequences revealed similarity between human and macaque genes used to encode some V3-directed MAbs. Our study sheds light on the timing and development of bnAbs in SHIV-infected macaques in comparison to HIV-1-infected humans and highlights the use of envelope trimer probes for efficient recovery of bnAbs.

Translocation of microbes and changes of immunocytes in the gut of rapid- and slow-progressor Chinese rhesus macaques infected with SIVmac239.

Human/simian immunodeficiency virus (HIV/SIV) infection can cause severe depletion of CD4(+) T cells in both plasma and mucosa; it also results in damage to the gut mucosa barrier, which makes the condition more conducive to microbial translocation. In this study, we used SIV-infected Chinese rhesus macaques to quantify the extent of microbial translocation and the function of immune cells in the entire gastrointestinal tract and to compare their differences between rapid and slow progressors. The results showed that in the slow progressors, microbial products translocated considerably and deeply into the lamina propria of the gut; the tissue macrophages had no significant differences compared with the rapid progressors, but there was a slightly higher percentage of mucosal CD8(+) T cells and a large amount of extracellular microbial products in the lamina propria of the intestinal mucosa of the slow progressors. The data suggested that although microbial translocation increased markedly, the mucosal macrophages and CD8(+) T cells were insufficient to clear the infiltrated microbes in the slow progressors. Also, therapies aimed at suppressing the translocation of microbial products in the mucosa could help to delay the progression of SIV disease.

The effects of TRIM5α polymorphism on HIV-2ROD and SIVmac239 replication in PBMCs from Chinese rhesus macaques and Vietnamese-origin cynomolgus macaques

Because of the difficulty of obtaining Indian-origin rhesus macaques, Chinese-origin rhesus macaques (CR) and Vietnamese-origin cynomolgus macaques (CM) are now used frequently in HIV/AIDS research. Nonetheless, the effects of TRIM5α polymorphism on viral replication in both CR and CM are unclear. To address these questions, we recruited 70 unrelated CR and 40 unrelated CM and studied the effect of TRIM5α polymorphism on HIV-2ROD and SIVmac239 replication in PBMCs. We found that 3 polymorphisms, located in the B30.2 domain of CR TRIM5α formed a haplotype and affected HIV-2ROD replication. In addition, we found that the variant Y178H, located in the Coiled-coil domain of CM TRIM5α, affected TRIM5α-mediated HIV-2ROD restriction. Finally, two polymorphisms, located in the Coiled-coil domain, altered anti-SIVmac239 activity in CR. We concluded that, CM TRIM5α polymorphism could alter HIV-2ROD infection; however, a different domain of CR TRIM5α was responsible for restricting different virus replication.

Identifying rhesus macaque gene orthologs using heterospecific human CNV probes.

We used the Affymetrix® Genome-Wide Human SNP Array 6.0 to identify heterospecific markers and compare copy number and structural genomic variation between humans and rhesus macaques. Over 200,000 human copy number variation (CNV) probes were mapped to a Chinese and an Indian rhesus macaque sample. Observed genomic rearrangements and synteny were in agreement with the results of a previously published genomic comparison between humans and rhesus macaques. Comparisons between each of the two rhesus macaques and humans yielded 206 regions with copy numbers that differed by at least two fold in the Indian rhesus macaque and human, 32 in the Chinese rhesus macaque and human, and 147 in both rhesus macaques. The detailed genomic map and preliminary CNV data are useful for better understanding genetic variation in rhesus macaques, identifying derived changes in human CNVs that may have evolved by selection, and determining the suitability of rhesus macaques as human models for particular biomedical studies.

Assessment of the hybridization between rhesus (Macaca mulatta) and long-tailed macaques (M. fascicularis) based on morphological characters.

Hybridization between rhesus (Macaca mulatta) and long-tailed (M. fascicularis) macaques has become a focal point of interest. The majority of such studies have evaluated their genetics, but not their morphological characters. We analyzed morphological characters of eight free-ranging populations of Indochinese rhesus and long-tailed macaques distributed at the proposed hybrid zone (15.75-21.58° N) in comparison with one population each of Chinese and Indian-derived rhesus macaques and three populations of Sundaic long-tailed macaques. Chinese and Indian rhesus macaques had a heavier body mass, longer crown-rump length, shorter relative facial length and relative tail length, and a greater contrast of reddish and yellowish dorsal pelage color than the Sundaic long-tailed macaques for which the latter three parameters could be used to visually discriminate between the two species. Although the morphological characters of Indochinese rhesus and long-tailed macaques were intermediate between the Chinese/Indian rhesus and Sundaic long-tailed macaques, they were more similar to their respective conspecifics. The species-specific characters of a shorter tail (<70%) and a bipartite pelage color pattern were retained in the Indochinese rhesus macaques while the longer tail (>90%) and no bipartite pattern was found in the Indochinese long-tailed macaques. No morphological cline was observed across the species and the variations were abrupt to some extent. The hybridization between rhesus and long-tailed macaques may be results of multiple contacts and isolations over a long period of time, thus their evolutionary history should not be drawn solely by genetic or morphological analysis.

Complete Taiwanese Macaque (Macaca cyclopis) Mitochondrial Genome: Reference-Assisted de novo Assembly with Multiple k-mer Strategy.

The Taiwanese (Formosan) macaque (Macaca cyclopis) is the only nonhuman primate endemic to Taiwan. This primate species is valuable for evolutionary studies and as subjects in medical research. However, only partial fragments of the mitochondrial genome (mitogenome) of this primate species have been sequenced, not mentioning its nuclear genome. We employed next-generation sequencing to generate 2 x 90 bp paired-end reads, followed by reference-assisted de novo assembly with multiple k-mer strategy to characterize the M. cyclopis mitogenome. We compared the assembled mitogenome with that of other macaque species for phylogenetic analysis. Our results show that, the M. cyclopis mitogenome consists of 16,563 nucleotides encoding for 13 protein-coding genes, 2 ribosomal RNAs and 22 transfer RNAs. Phylogenetic analysis indicates that M. cyclopis is most closely related to M. mulatta lasiota (Chinese rhesus macaque), supporting the notion of Asia-continental origin of M. cyclopis proposed in previous studies based on partial mitochondrial sequences. Our work presents a novel approach for assembling a mitogenome that utilizes the capabilities of de novo genome assembly with assistance of a reference genome. The availability of the complete Taiwanese macaque mitogenome will facilitate the study of primate evolution and the characterization of genetic variations for the potential usage of this species as a non-human primate model for medical research.

High immune activation and abnormal expression of cytokines contribute to death of SHIV89.6-infected Chinese rhesus macaques.

Chinese rhesus macaques (CRMs) are ideal experimental animals for studying the pathogenesis of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) and for vaccine research. SHIV89.6 has been reported to be an attenuated virus because, in most cases, SHIV89.6 infection only causes limited alteration of immune cells and tissues, and it has been used commonly for vaccine research. After two serial passages in vivo, SHIV (SHIV-89.6P) induces CD4 lymphopenia and an AIDS-like disease with wasting and opportunistic infections. However, the pathogenic ability of SHIV89.6 is not well understood. In this study, we found that 6 of 14 SHIV89.6-infected CRMs died within 127 weeks after infection. We found especially high immune activation, low IFN-α expression, and distinctive cytokine expression profiles in the infected and dead (ID) group of monkeys, while there was only few change in the CD4(+) T counts and distribution of T cell subsets in the ID group monkeys. Also, there was a similar dynamic of viral load between infected and surviving (IS) and ID group monkeys. Furthermore, we found various correlations among immune activation, IFN-α expression, and frequencies of cytokine-secreting cells. These results suggest that SHIV89.6 infections have pathogenic potential in CRMs and that high immune activation and abnormal expression of cytokines contribute to death of SHIV89.6-infected CRMs. This also implies that high immune activation may be relevant to dysfunction of immune cells. It is proposed that high immune activation and dysfunction of immune cells may be good predictors for disease progression and markers for therapy.

Correlation of central memory CD4+ T-Cell decrease in the peripheral blood with disease progression in SIVmac251-infected Chinese rhesus macaques.

Correlation of CD4(+) Tcm cells in the peripheral blood to disease progression in SIVmac251 infection was examined in Chinese rhesus macaques. Plasma viral RNA loads were measured by a quantitative real-time reverse transcription-PCR (qRT-PCR) assay for SIV gag. Disease progression was determined based on time of survival. Phenotyping of CD4(+) T-cell subsets in the peripheral blood was longitudinally performed by flow cytometry. Although CD4(+) T-cell decrease and low CD4(+)/CD8(+) T-cell ratio in the peripheral blood after SIVmac251 infection did not correlate with disease progression, CD4(+) Tcm cell decrease was observed to be correlated to disease progression in the SIVmac251-infected Chinese rhesus macaques. Our findings suggest that CD4(+) Tcm cell decrease could be used as a predictive marker for defining the pathogenesis of the SIV disease and consequently HIV/SIV vaccine efficacy in Chinese rhesus macaques.

Immune restoration, activation and viral reservoirs in gut-associated lymphoid tissue in SIV-infected long-term nonprogressing Chinese rhesus macaques on antiretroviral therapy (VIR1P.1130)

Abstract HIV infected long-term nonprogressors (LTNPs) and elite controllers (ECs) maintain enduring control of HIV infection without antiretroviral therapy. However, persistent tissue reservoirs and chronic inflammation still exist. We previously found that 1/3 of SIV-infected Chinese rhesus macaques mimics HIV-infected LTNPs/ECs. Here we studied whether therapy can further decrease tissue reservoirs, restore immune function and decrease inflammation in this model. Six LTNPs/ECs and 4 progressors were treated with PMPA and FTC daily for up to 24 weeks during chronic infection. Blood, lymph nodes and gut tissues were collected. Cell-associated viral DNA levels from purified CD4+ T cells in blood and gut lymphocytes were quantified by real-time PCR. The size of reservoirs was evaluated by quantitative coculture assays and real-time PCR. Immune cells restoration including IL-17+ subsets, proliferation and immune activation were monitored by flow cytometry. We found that plasma viral loads in all animals were suppressed and maintained to undetectable throughout ART. The levels of IL-17 expression in CD4 and CD8 T cells were not fully restored but slightly increased after ART. Immune activation significantly decreased. In conclusion, the ChRM nonhuman primate model is excellent for testing novel therapeutic interventions on TP and LTNPs/ECs for HIV eradication. Initiation of ART may be necessary for improvement of immune function for HIV/SIV infected LTNP/ECs.

Evolutionary distance of amino acid sequence orthologs across macaque subspecies: identifying candidate genes for SIV resistance in Chinese rhesus macaques.

We use the Reciprocal Smallest Distance (RSD) algorithm to identify amino acid sequence orthologs in the Chinese and Indian rhesus macaque draft sequences and estimate the evolutionary distance between such orthologs. We then use GOanna to map gene function annotations and human gene identifiers to the rhesus macaque amino acid sequences. We conclude methodologically by cross-tabulating a list of amino acid orthologs with large divergence scores with a list of genes known to be involved in SIV or HIV pathogenesis. We find that many of the amino acid sequences with large evolutionary divergence scores, as calculated by the RSD algorithm, have been shown to be related to HIV pathogenesis in previous laboratory studies. Four of the strongest candidate genes for SIVmac resistance in Chinese rhesus macaques identified in this study are CDK9, CXCL12, TRIM21, and TRIM32. Additionally, ANKRD30A, CTSZ, GORASP2, GTF2H1, IL13RA1, MUC16, NMDAR1, Notch1, NT5M, PDCD5, RAD50, and TM9SF2 were identified as possible candidates, among others. We failed to find many laboratory experiments contrasting the effects of Indian and Chinese orthologs at these sites on SIVmac pathogenesis, but future comparative studies might hold fertile ground for research into the biological mechanisms underlying innate resistance to SIVmac in Chinese rhesus macaques.

HIV-1 vaccines based on replication-competent Tiantan vaccinia protected Chinese rhesus macaques from simian HIV infection.

To assess the efficacy of HIV vaccines constructed from replication-competent Tiantan vaccinia virus (rTV) alone or combined with DNA in protecting Chinese rhesus macaques from homologous Simian/Human Immunodeficiency Virus (SHIV)-CN97001 challenge. The nef, gag, pol, and gp140 genes from strain CRF07_BC HIV-1 CN54 were selected to construct an HIV vaccine using the rTV or rTV/DNA vaccine. After vaccination, the vaccine and control groups were intravenously challenged with SHIV-CN97001 (32 MID50). HIV-specific antibodies and neutralizing antibodies, gp70 V1V2 binding antibodies, and cytotoxic T-lymphocyte responses were measured prospectively after vaccination with an ELISA, a virus infectivity assay in TZM-bl cells, and ELISPOT assays, respectively. Viral RNA was quantified after challenge with real-time reverse transcriptase-PCR (RT-PCR), and protection efficacy was determined with an analysis of CD8 lymphocyte depletion in vivo. Both rTV and DNA/rTV vaccine groups developed strong cellular and humoral responses against HIV-1 CN54 antigens, including Gag and Env, and also developed significant and persistent anti-Env antibodies and neutralizing antibodies after immunization. Both the rTV and DNA/rTV groups were significantly protected against SHIV-CN97001 or displayed lower viremia than the controls. After CD8 lymphocyte depletion, no viremia was detectable in the vaccinated monkeys, but rebounded rapidly in the control animals. Protection against infection correlated with vaccine-elicited neutralizing antibodies specific for homologous HIV-1 viruses. An rTV-based HIV-1 vaccine, with or without a DNA primer, provided protection from SHIV challenge in a macaque model. Replication-competent Tiantan vaccinia is a promising vector and should enable advances in HIV-1 vaccine development.

CYP2D44 polymorphisms in cynomolgus and rhesus macaques.

Macaques, including cynomolgus and rhesus macaques, are important animal species used in drug metabolism studies. CYP2D44 is expressed in cynomolgus macaque liver and encodes a functional drug metabolizing enzyme, metabolizing typical human CYP2D substrates such as bufuralol and dextromethorphan. CYP2D44 is highly homologous to human CYP2D6 that is known to be polymorphic with a large inter-individual variation in metabolic activities, however, genetic polymorphisms have not been investigated in macaque CYP2D44. In the present study, screening of 78 cynomolgus and 40 rhesus macaques found a total of 67 variants, including 64 non-synonymous variants, 1 nonsense mutation, and 2 frameshift mutations, and 1 gene conversion, of which 14, 19, and 15 variants were unique to Indochinese cynomolgus macaques, Indonesian cynomolgus macaques, and Chinese rhesus macaques, respectively. Eleven of the 64 non-synonymous variants were located in substrate recognition sites, the regions important for protein function. By site-directed mutagenesis and metabolic assays, S175N, V185L, A235G, R242G, R245K, and N337D showed substantially decreased activity in bufuralol 1'-hydroxylation as compared with wild-type proteins. Moreover, two null alleles (c.128T>del and c.664G>T) were found in Indonesian cynomolgus macaques, but not in Indochinese cynomolgus macaques or Chinese rhesus macaques. These results suggest that genetic polymorphisms might account for the variability of CYP2D44-dependent metabolism in macaques.

Inducible nitric oxide synthase (iNOS) regulatory region variation in non-human primates

Inducible nitric oxide synthase (iNOS) is an enzyme that plays a key role in intracellular immune response against respiratory infections. Since various species of nonhuman primates exhibit different levels of susceptibility to infectious respiratory diseases, and since variation in regulatory regions of genes is thought to play a key role in expression levels of genes, two candidate regulatory regions of iNOS were mapped, sequenced, and compared across five species of nonhuman primates: African green monkeys (Chlorocebus sabaeus), pig-tailed macaques (Macaca nemestrina), cynomolgus macaques (Macaca fascicularis), Indian rhesus macaques (Macaca mulatta), and Chinese rhesus macaques (M. mulatta). In addition, we conducted an in silico analysis of the transcription factor binding sites associated with genetic variation in these two candidate regulatory regions across species. We found that only one of the two candidate regions showed strong evidence of involvement in iNOS regulation. Specifically, we found evidence of 13 conserved binding site candidates linked to iNOS regulation: AP-1, C/EBPB, CREB, GATA-1, GATA-3, NF-AT, NF-AT5, NF-κB, KLF4, Oct-1, PEA3, SMAD3, and TCF11. Additionally, we found evidence of interspecies variation in binding sites for several regulatory elements linked to iNOS (GATA-3, GATA-4, KLF6, SRF, STAT-1, STAT-3, OLF-1 and HIF-1) across species, especially in African green monkeys relative to other species. Given the key role of iNOS in respiratory immune response, the findings of this study might help guide the direction of future studies aimed to uncover the molecular mechanisms underlying the increased susceptibility of African green monkeys to several viral and bacterial respiratory infections.

Comprehensive identification of high-frequency and combination MHC-DMA and -DMB alleles in a cohort of Chinese rhesus macaques and cynomolgus macaques of Vietnamese origin

Rhesus and cynomolgus macaques are currently used as ideal animal models of immune response. Major histocompatibility complex (MHC) molecules play important roles in the susceptibility and/or resistance to many diseases. In this study, MHC-DMA and -DMB were first characterized by sequencing and cloning in 28 unrelated cynomolgus macaques from Vietnam and 34 unrelated Chinese rhesus macaques. A total of 23 novel alleles, including six high frequency alleles, were identified in this study. Our results showed that the alleles with the highest phenotypic frequencies were Mafa-DMA∗02:04:03 (57.1%), Mafa-DMB∗03:01:02 (76.9%), Mamu-DMA∗02:01:04 (88.2%), and Mamu-DMB∗03:02:02 (85%), respectively, indicating that distribution and frequencies of alleles had a few differences between Chinese rhesus macaques and cynomolgus macaques from Vietnam. Interestingly, compared to the cynomolgus macaques, we found that the combination of Mamu-DMA∗02:01:04-DMB∗03:02:02 was detected in 27 (79.4%) of 34 monkeys, suggesting that the combination of the MHC-DMA and -DMB alleles was probably a characteristic feature of the Chinese rhesus macaques. Our results will greatly increase the value of the two species as models for biomedical research.

The recombinant maize ribosome-inactivating protein transiently reduces viral load in SHIV89.6 infected Chinese Rhesus Macaques.

Ribosome inactivating proteins (RIPs) inhibit protein synthesis by depurinating the large ribosomal RNA and some are found to possess anti-human immunodeficiency virus (HIV) activity. Maize ribosome inactivating protein (RIP) has an internal inactivation loop which is proteolytically removed for full catalytic activity. Here, we showed that the recombinant active maize RIP protected chimeric simian-human immunodeficiency virus (SHIV) 89.6-infected macaque peripheral blood mononuclear cells from lysis ex vivo and transiently reduced plasma viral load in SHIV89.6-infected rhesus macaque model. No evidence of immune dysregulation and other obvious side-effects was found in the treated macaques. Our work demonstrates the potential development of maize RIP as an anti-HIV agent without impeding systemic immune functions.

Lipopolysaccharide Increases Immune Activation and Alters T Cell Homeostasis in SHIVB’WHUChronically Infected Chinese Rhesus Macaque

Immune activation plays a significant role in the disease progression of HIV. Microbial products, especially bacterial lipopolysaccharide (LPS), contribute to immune activation. Increasing evidence indicates that T lymphocyte homeostasis disruptions are associated with immune activation. However, the mechanism by which LPS affects disruption of immune response is still not fully understood. Chronically SHIVB'WHU-infected Chinese rhesus macaques received 50 μg/kg body weight LPS in this study. LPS administration affected the virus/host equilibrium by elevating the levels of viral replication and activating T lymphocytes. LPS induced upregulation of CD8+ naïve T cells and downregulated the number of CD4+ and CD8+ T effector memory cells. The downregulated effector memory cells are associated with a lower frequency of monofunctional and polyfunctional cells, and an upregulated programmed cell death-1 (PD-1) expression on CD4+ and CD8+ T cells was observed in monkeys after LPS stimulation. Our data provide new insights into the function of LPS in the immune activation in SHIV/HIV infection.

Flow cytometric characterizations of leukocyte subpopulations in the peripheral blood of northern pig-tailed macaques (Macaca leonina).

Pig-tailed macaques (Macaca nemistrina group) have been extensively used as non-human primate animal models for various human diseases in recent years, notably for AIDS research due to their sensitivity to HIV-1. Northern pig-tailed macaques (M. leonina) are distributed in China and other surrounding Southeast Asia countries. Although northern pig-tailed macaques have been bred on a large scale as experimental animals since 2012, the reference value of normal levels of leukocytes is not available. To obtain such information, 62 blood samples from male and female healthy northern pig-tailed macaques at different ages were collected. The normal range of major leukocyte subpopulations, such as T lymphocytes, B lymphocytes, natural killer (NK) cells, monocytes, and the expression levels of activation or differentiation related molecules (CD38, HLA-DR, CCR5, CD21, IgD, CD80 and CD86) on lymphocytes were analyzed by flow cytometry. The counts of B cells decreased with age, but those of CD8(+) T cells and NK cells and the frequency of CD38(+)HLA-DR(+)CD4(+) T cells were positively correlated with age. The counts of leukocyte subpopulations were higher in males than those in females except for CD4(+) T cells. Males also showed higher expression levels of IgD and CD21 within B cells. This study provides basic data about the leukocyte subpopulations of northern pig-tailed macaques and compares this species with commonly used Chinese rhesus macaques (M. mulatta), which is meaningful for the biomedical application of northern pig-tailed macaques.