Chinese Rhesus Research Articles

Comprehensive transcriptomic analyses identify the immunosuppressive effects of LLDT-8 in ART-treated SIV-infected rhesus macaques

BackgroundChronic immune activation plays a significant role in the pathogenesis and disease progression of human immunodeficiency virus (HIV), and the existing interventions to address this issue are limited. In a phase II clinical trial, (5R)-5-hydroxytriptolide (LLDT-8) demonstrated promising potential in enhancing CD4+ T cell recovery. However, the therapeutical effects of LLDT-8 remained to be systemic explored. MethodsTo assess the treatment effects of LLDT-8, we conducted flow cytometry and RNA-seq analyses on eight Chinese rhesus monkeys infected with simian immunodeficiency virus (SIV). Additionally, we performed comprehensive transcriptomic analyses, including cross-sectional and longitudinal differentially expressed gene (DEG) analysis, gene set enrichment analysis (GSEA), weighted gene co-expression network analysis (WGCNA), and deconvolution analysis using peripheral blood mononuclear cell (PBMC) samples from 14-time points. These findings were further validated with RNA-seq analysis on patients who received LLDT-8 treatment, along with in vitro cellular experiments using human PBMCs. ResultsFlow cytometry analysis revealed that LLDT-8 treatment significantly reduced the percentage of HLA-DR+CD38+CD8+ T cells in SIV-infected rhesus monkeys (P < 0.001). The cross-sectional and longitudinal analysis identified 2531 and 1809 DEGs, respectively. GSEA analysis indicated that LLDT-8 treatment led to significant downregulation of proliferation-related pathways, such as E2F targets, G2M checkpoint, and mitotic spindle pathways. WGCNA analysis identified two modules and 202 hub genes associated with CD8 activation levels. Deconvolution analysis showed a significant decrease in the proportion of CD8+ T cells and activated CD4+ T cells during LLDT-8 treatment. Gene ontology results demonstrated that the common DEGs between LLDT-8-treated patients and rhesus monkeys were primarily enriched in cell activation and cell cycle progression. Furthermore, in vitro cellular experiments validated the consistent impact of LLDT-8 in inhibiting proliferation, activation (HLA-DR and CD38 expression), exhaustion (PD-1 expression), and IFN-γ production in human CD4+ and CD8+ T cells. ConclusionLLDT-8 exhibited notable efficacy in alleviating immune activation in both an in vivo animal model and in vitro human cell experiments. These findings suggest that LLDT-8 may hold potential as a drug for managing systemic immune activation associated with SIV/HIV infection, warranting further prospective clinical exploration.

Effect of age and sex on hematological and biochemical parameters in Chinese rhesus monkeys (Macaca mulatta) anesthetized with ketamine.

Rhesus monkeys are increasingly used in biomedical research, which makes their hematological and biochemical parameters increasingly important in preclinical research. Since age and sex can influence blood parameters, establishing reference intervals for such parameters based on age and sex becomes along with identifying the effect of age and sex on those parameters. A total of 1385 healthy Chinese rhesus monkeys (548 males and 837 females) anesthetized with ketamine were selected and segregated by age (six groups) and sex. A total of 21 hematological and 26 biochemical parameters were measured, and the effects of age and sex were analyzed. We established baseline indices for hematological and biochemical parameters based on age and sex, separately, and observed significant impacts of age, sex, and age-sex interactions on blood parameters. Among different age groups, significant differences were found in WBC, NEUT%, LYM%, EO%, LYM#, EO#, MCV, RDW-CV, PLT, MPV, PDW, PCT, TP, Alb, GLB, A/G, ALT, AST, ALP, TBIL, GGT, BUN, Cre, GLU, CK, TRIG, LDL, HCY, IL-6 FOL, Vit B12, VIT D-T, PTH, and AMH. Additionally, significant differences were observed in RBC, HGB, HCT, MPV, Alb, BUN, Cre, GLU, CHOL, TRIG, HDL, LDL, HCY, and VIT D-T between the two sexes. An age-sex interaction exerted a significant effect on WBC, NEUT#, MCV, MCHC, PDW, GLB, ALP, Cre, CHOL, TRIG, HDL, LDL, HCY, IL-6, Vit B12, VIT D-T. However, neither age, sex, and age-sex interactions exerted significant effects on MO%, MOMO#, MCH, RDW-SD, CRP, and CT. Our study investigated the blood parameters of rhesus monkeys to provide a reference basis for rhesus monkey-related scientific experimental research.

Longitudinal white matter alterations in SIVmac239-infected rhesus monkeys with and without regular cART treatment.

To use SIV-mac239-infected Chinese rhesus monkeys to study white matter changes with and without regular combined antiretroviral therapy (cART) and the relationships between the changes and clinical results. Diffusion tensor imaging (DTI) data were collected at baseline and 10 days, 4 weeks, 12 weeks, 24 weeks, and 36 weeks after viral inoculation. Plasma CD4 T cell counts, CD4/CD8 ratio, plasma viral load, and cerebrospinal fluid (CSF) viral load were collected at baseline and 1 week, 5 weeks, 12 weeks, 24 weeks, and 36 weeks after viral inoculation. Microstructural characteristics were examined within 76 white matter areas defined by the DTI-white matter (WM) atlas for rhesus macaques. Corrections for multiple comparisons were performed using a false discovery rate (p < 0.05, FDR). Correlation analyzes between imaging markers and clinical markers (plasma CD4 T cell counts, CD4/CD8 ratio, plasma viral load, and cerebral spinal fluid viral load) were performed using Pearson correlations. White matter changes in SIV-infected macaques were detected in different brain regions as early as 4 weeks after inoculation. As time progressed, cART reversed, ameliorated, or even enhanced the effects. The CD4 T cell count was mainly associated with DTI metrics before cART, while the CD4/CD8 ratio was associated with white matter changes with and without cART. Viral load was positively associated with mean diffusivity in HIV patients without cART, and the opposite results were seen in HIV patients with cART. SIV-mac239 infection may be an ideal tool for studying HIV-induced changes in the brain. The first white matter changes appeared in a structure adjacent to the periventricular area as early as 4 weeks after inoculation. As time progressed, cART had different effects on different regions, reversing, attenuating, or even progressing the pathology. Moreover, these changes were closely related to the CD4/CD8 ratio and viral load, even after cART.

Therapeutic effect of (5R)-5-hydroxytriptolide (LLDT-8) in SIV infected rhesus monkeys

BackgroundsHuman immunodeficiency virus (HIV) infections induce robust, generalized inflammatory responses and lead to pathological systemic immune activation. This abnormal immune status persists despite successful antiretroviral therapy (ART). Immune modulating strategies in conjunction with ART were tried to reduce abnormal immune activation. Previously, we demonstrated that Tripterygium Wilfordii Hook F has been shown immunosuppressive activity in HIV patients. (5R)-5-hydroxytriptolide (LLDT-8), a new analog of triptolide, and the most active ingredient of Tripterygium Wilfordii Hook F, has been shown to have lower cytotoxicity. However, the role of LLDT-8 in HIV or simian immunodeficiency virus (SIV) needs to be explored. MethodsSix male adult Chinese rhesus monkeys were enrolled in our study. All of them were healthy and negative for SIV, and chronically SIVmac239 infected macaques were treated with LLDT-8 combined with ART (n = 4) or ART only (n = 2) after 14 weeks of infection. ART was determined at week 33, and LLDT-8 was continued until week 48. T cell immune activation and inflammation were compared during the period, and viral rebound time and reservoir were supervised after stopping ART. ResultsThe RNA level of the two groups continued to decline after initiating ART, RNA of 4 rhesus monkeys declined to the lower limit of detection at week 20. LLDT-8 administration combined with ART did not affect T cell activation and plasma levels of IL-6 and CRP. The viral load of all the macaques in both groups was rebounded 2 weeks after ART discontinuation. Furthermore, no significant decrease of SIV DNA was observed in the LLDT-8 treatment group. ConclusionsLLDT-8 administration during chronic SIV infection had no effect on T cell activation and plasma levels; Furthermore, LLDT-8 may not contribute to suppression of viral rebound and reservoir. These results suggest that LLDT-8 is unlikely to reduce immune activation and viral persistence without additional interventions.

Infection of Chinese Rhesus Monkeys with a Subtype C SHIV Resulted in Attenuated In Vivo Viral Replication Despite Successful Animal-to-Animal Serial Passages.

Rhesus macaques can be readily infected with chimeric simian-human immunodeficiency viruses (SHIV) as a suitable virus challenge system for testing the efficacy of HIV vaccines. Three Chinese-origin rhesus macaques (ChRM) were inoculated intravenously (IV) with SHIVC109P4 in a rapid serial in vivo passage. SHIV recovered from the peripheral blood of the final ChRM was used to generate a ChRM-adapted virus challenge stock. This stock was titrated for the intrarectal route (IR) in 8 ChRMs using undiluted, 1:10 or 1:100 dilutions, to determine a suitable dose for use in future vaccine efficacy testing via repeated low-dose IR challenges. All 11 ChRMs were successfully infected, reaching similar median peak viraemias at 1–2 weeks post inoculation but undetectable levels by 8 weeks post inoculation. T-cell responses were detected in all animals and Tier 1 neutralizing antibodies (Nab) developed in 10 of 11 infected ChRMs. All ChRMs remained healthy and maintained normal CD4+ T cell counts. Sequence analyses showed >98% amino acid identity between the original inoculum and virus recovered at peak viraemia indicating only minimal changes in the env gene. Thus, while replication is limited over time, our adapted SHIV can be used to test for protection of virus acquisition in ChRMs.

SIV infection aggravates malaria in a Chinese rhesus monkey coinfection model

BackgroundThe co-occurrence of human immunodeficiency virus (HIV) infection and malaria in humans in endemic areas raises the question of whether one of these infections affects the course of the other. Although epidemiological studies have shown the impact of HIV infection on malaria, the mechanism(s) are not yet fully understood. Using a Chinese rhesus macaque coinfection model with simian immunodeficiency virus (SIV) and Plasmodium cynomolgi (Pc) malaria, we investigated the effect of concurrent SIV infection on the course of malaria and the underlying immunological mechanism(s).MethodsWe randomly assigned ten Chinese rhesus monkeys to two groups based on body weight and age. The SIV-Pc coinfection animals (S + P group) were infected intravenously with SIVmac251 eight weeks prior to malaria infection, and the control animals (P group) were infected intravenously with only Pc-infected red blood cells. After malaria was cured with chloroquine phosphate, we also initiated a secondary malaria infection that lasted 4 weeks.We monitored body weight, body temperature and parasitemia, measured SIV viral loads, hemoglobin and neopterin, and tracked the CD4+, CD8+, and CD4+ memory subpopulations, Ki67 and apoptosis by flow cytometry. Then, we compared these parameters between the two groups.ResultsThe animals infected with SIV prior to Pc infection exhibited more severe malaria symptoms characterized by longer episodes, higher parasitemia, more severe anemia, greater body weight loss and higher body temperature than the animals infected with Pc alone. Concurrent SIV infection also impaired immune protection against the secondary Pc challenge infection. The coinfected animals showed a reduced B cell response to Pc malaria and produced lower levels of Pc-specific antibodies. In addition, compared to the animals subjected to Pc infection alone, the animals coinfected with SIV and Pc had suppressed total CD4+ T cells, CD4+CD28highCD95high central memory T cells, and CD4+CD28lowCD95− naïve T cells, which may result from the imbalanced immune activation and faster CD4+ T cell turnover in coinfected animals.ConclusionsSIV infection aggravates malaria physiologically and immunologically in Chinese rhesus monkeys. This nonhuman primate SIV and Pc malaria coinfection model might be a useful tool for investigating human HIV and malaria coinfection and developing effective therapeutics.

ABO blood group phenotype frequency estimation using molecular phenotyping in rhesus and cynomolgus macaques.

A much larger sample (N = 2369) was used to evaluate a previously reported distribution of the A, AB and B blood group phenotypes in rhesus and cynomolgus macaques from six different regional populations. These samples, acquired from 15 different breeding and research facilities in the United States, were analyzed using a real-time quantitative polymerase chain reaction (qPCR) assay that targets single nucleotide polymorphisms (SNPs) responsible for the macaque A, B and AB phenotypes. The frequency distributions of blood group phenotypes of the two species differ significantly from each other and significant regional differentiation within the geographic ranges of each species was also observed. The B blood group phenotype was prevalent in rhesus macaques, especially those from India, while the frequencies of the A, B and AB phenotypes varied significantly among cynomolgus macaques from different geographic regions. The Mauritian cynomolgus macaques, despite having originated in Indonesia, showed significant (P ≪ .01) divergence from the Indonesian animals at the ABO blood group locus. Most Mauritian animals belonged to the B blood group while the Indonesian animals were mostly A. The close similarity in blood group frequency distributions between the Chinese rhesus and Indochinese cynomolgus macaques demonstrates that the introgression between these two species extends beyond the zone of intergradation in Indochina. This study underscores the importance of ABO blood group phenotyping of the domestic supply of macaques and their biospecimens.

Experimental observation of SIVmac239 Chinese rhesus monkey model at sub-acute phase of AIDS

To observe T lymphocyte subsets and indicators of changes in viral load in sub-acute period in Chinese rhesus monkey model of AIDS SIVmac239. To explore Virology related index variation in sub-acute period of the Chinese rhesus monkey model of AIDS. To replicate Chinese rhesus monkey model of AIDS, healthy Chinese rhesus monkey was inoculated with SIVmac239 viral strain. To observe changes in T lymphocyte subsets indexes and viral load after infection with the simian immunodeficiency virus (SIV) in sub-acute period on an animal model. The clinical symptoms of the animal model was recorded simultaneously. During the 10 weeks after SIV acute infection, body weight and BMI index were relatively stable, the difference was not significant at all time points. Twelve monkeys were tested SIV positive by real-time PCR after three days of infection. On the 7th day after infection, 15 monkeys were tested SIV positive. Viral load increased rapidly, but reached a peak on the 10th-14th day after infection, then showed a level of volatility decline. T lymphocyte subsets showed significant changes, among them, CD3% and CD3 counts fluctuated upward trend and reached to the highest level in two weeks after infection; of CD4% and CD4 count changes were not synchronized, CD4% declined trend while the CD4 count was an increasing trend after the infection; of CD8% and CD8 counts fluctuate upward trend, and reached to a highest level in two weeks after infection ;the ratio of CD4/CD8 and the counts of CD4CD28 T cells decreased significantly in two weeks after infection; the former followed by a slow decline, the latter followed by a rapid rise. Three mouths after the infection 3 monkeys showed significant clinical symptoms. One of the rhesus monkeys had symptoms of diarrhea and two of them had reduced food intake. This experiments established standardization of Chinese Rhesus monkeys used in the research of AIDS and provide a detailed contents in the changes of sub-acute phase.

How well do you know your monkeys?

We read with interest the letter to the editor titled “How well do you know your monkey model” (1), written in response to our review article “The nonhuman primate model of tuberculosis” (J Med Primatol 41: 191–201) (2). This letter, by Engels and colleagues, raises an important issue about the use of the tuberculin skin test (TST) to detect Mycobacterium tuberculosis (Mtb) infection in nonhuman primates (NHPs). While we tend to agree with their general philosophy that improved detection of tuberculosis (TB), in particular latent TB, requires the development of more robust technologies, their understanding of our model is inherently flawed. The authors take for granted that all NHPs used in biomedical research are imported from nondomestic source countries. This is just not the case. The source of all Indian origin rhesus macaques in the US since the late 1970s has been from domestic breeding colonies. This was necessitated by a global ban on the export of Indian rhesus macaques by the government of India at that time. Since then, all Indian origin rhesus macaques at the NPRCs have been domestically bred and the animals are extremely well characterized with respect to infectious diseases such as tuberculosis (TB). As the authors state, rigorous preventive medicine programs have focused on maintaining negative TB status in domestic NHP colonies for many years. The authors are correct that the highest risk of TB infection in NHP occurs in animals imported from nondomestic sources. As a result, a best practice with respect to such animals is to keep them completely segregated from domestically bred NHPs. NHP originating from areas where TB is prevalent in the human population are extensively screened prior to inclusion at these NPRCs, or not used for TB research studies. Well-characterized domestic sources of NHP or NHP imported from areas without endemic TB are considered for these particular studies. It is the result of these strategies, that no TB outbreak has been detected at the TNPRC amongst domestically bred macaques, for more than two decades now. The author’s contention that “TST commonly fails to detect infection” is an overstatement, at least with respect to rhesus macaques. In an outbreak at the TNPRC close to 10 years ago in imported Chinese origin rhesus monkeys, the TST was diagnostic and was the screening method used to effectively identify cases and contain infection to a single room. Admittedly, adding other testing modalities increased our ability to confirm the diagnosis in this particular group of animals. The relatively low incidence of spontaneous TB cases in the literature compared to the number of domestic NHP used in research is a testament to the effectiveness of the TST used as a screening tool. If the TST “commonly” failed to detect cases of TB in domestic breeding colonies these colonies would have a much greater prevalence of disease than is currently noted. This contention is also supported by experimental data. In almost 125 Indian rhesus macaques experimentally infected since 2005, with Mtb CDC1551, H37Rv, Erdman or defined mutants of Mtb (3–8, unpublished results), here at the TNPRC, TST was able to detect Mtb infection. In many of these studies, which involved a vaccination component (6–8), TST always detected vaccination with BCG as well. In fact, we found no difference in the ability of TST and PRIMAGAM® (an interferon-gamma release assay comparable to QUANTIFERON-GOLD®) to detect experimental Mtb infection in domestically bred Indian rhesus at identical time-points. There is no argument that better TB diagnostic assays need to be developed and that the TST is far from a perfect screening tool. This is the driving force behind the development of nucleic acid based diagnostic tests for detecting human infections. However, the enthusiasm for such tests is dampened by the requirement for technology and infrastructure in resource-limited settings.

Partial Protection of SHIV-Infected Chinese Rhesus Macaques Against Super-Infection with Heterologous SHIV Isolate

Many studies have revealed a protective effect of infection with simian immunodeficiency virus (SIV) or simian-human immunodeficiency virus (SHIV) against subsequent infection by a related immunodeficiency virus. However, whether a protective response can be induced by an infection with an immunodeficiency virus is still currently debated in the HIV-1 vaccine field. The aim of this study was to evaluate the protection against SHIV challenge in Chinese macaques that had been inoculated with SHIVs containing different HIV-1 envelops. Eleven adult Chinese rhesus monkeys were inoculated with SHIV-KB9, SHIV-1157ipd3N4 or SHIV-CN97001. After 30 weeks, the animals were exposed to SHIV-KB9 or SHIV-CN97001, which carried a heterologous envelope protein relative to the first challenge strain. Infection was monitored by measuring viral load and antibody response, as well as viral genome sequence analyses. After first challenge, all the monkeys demonstrated high viral loads and specific antibody responses. Protection from super-infection was statistically significant in all the animals inoculated with SHIV-KB9 or SHIV-1157ipd3N4. However, animals inoculated with SHIV-CN97001 and challenged with SHIV-KB9 showed new infections. The susceptibility to super-infection was not correlated with neutralizing antibodies present at the time of exposure to the second virus. These findings indicate that different SHIV infection may confer different levels of protection against a second SHIV infection in Chinese monkeys. Understanding this protective response in SHIV infected macaques may shed a new light on HIV-1 vaccine development.

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.

Reference values of hematology, chemistry, electrolytes, blood gas, coagulation time, and urinalysis in the Chinese rhesus macaques (Macaca mulatta)

Due to increasing preclinical study using the rhesus monkeys, the physiological data of these monkeys are very important for the objective evaluation of experimental results. Here, we report the physiological values of the Chinese rhesus monkeys acclimated under a well-controlled laboratory environment. Seventy healthy rhesus monkeys of both genders (29 males and 41 females) were used in this study. Available data on hematology, serum biochemistry, electrolytes, blood gas, coagulation time, urinalysis, water consumption, urine volume, and body weight were examined. The lymphocyte values were 1.5-2.5 times higher than the neutrophil values in both genders. In serum biochemistry, there was no significant difference between the two genders. Interestingly, the values of alkaline phosphatase from the monkeys were very high. According to isoenzyme analysis, the percentage of alkaline phosphatase that originated from the bone was 60%, and this value was significantly higher than that from the liver (39%, P = 0.020). Physiological data are very important parameters that can be directly and indirectly related to organ function (e.g. islet, kidney, liver, heart, etc.) in the transplantation model. In this respect, our data constitute valuable references for preclinical study using the Chinese rhesus monkeys.

Comparison of bio-medical parameters in SIV infected Chinese rhesus monkeys with diverse progression correlated to the pathogenesis of simian AIDS

Objective To compare the bio-medical parameters in SIV infected Chinese rhesus monkeys with diverse disease progression,by which the pathogenesis of simian AIDS were to be investigated.Methods Sixteen Chinese rhesus monkeys were inoculated intravenously with SIVmac239 and followed-up for 18 months.Based on their progression patterns and plasma viral loads,animals were divided into 3 groups,including 1 rapid progressor( RP),13 normal progressors(NP),and 2 elite controllor(EC).Their parameters of haematology,virology,immunology and pathology were examined and compared. Results Compared with other animals,RM449(RP) showed higher viral load,unresponsive humoral immunity,and higher level of auto-antibodies against lymph node,thymus,and spleen.Additionally,its effector memory CD4 count was lower,with the transformation progress being blocked-like from naive/central memory subsets to effector memory subset,as the flow-cytometry assay showed.Notable decrease in its peripheral B cell was also observed,especially to the sub-population of tissue-like memory B cells and activated memory B cells.Pathological examination showed the depletion of lymphoid tissue,atrophy of spleen and loss of thymus.Moreover,most of these parameters of RM450 and RM453 (EC) changed opposite to that of RP.Conclusion The hallmarks of RM449 were higher viraemia and lower SIV specific IgG level,which may due to the disturbance of T cells and B cells development and differentiation.Moreover,destructions of organs of the immune system may contribute to the disturbance.Our study suggest that the change of micro-environments of thymus induced by SIV infection,which is necessary in T cell and B cell development and differentiation,may contribute at least partially to the AIDS pathogenesis. Key words: Rapid progressor(RP); Normal progressor(NP); Elite controllor (EC); Simian immunodeficiency virus(SIV); Memory cell subset

Effectiveness of Ganoderma lucidum preparation in treating simian acquired immune deficiency syndrome

To explore the effectiveness of the traditional Chinese herbal medicine Lingzhi (Ganoderma lucidum) preparation in treating simian acquired immune deficiency syndrome (SAIDS). Five female adult Chinese rhesus monkeys were inoculated rectally with SIVmac239, and were all diagnosed as SAIDS by laboratory and clinical examinations 17 months later. Of these 5 monkeys, 3 (#393, #374, and #381; treatment group) were orally administered with Ganoderma lucidum (2 spores powder capsules plus 2 spores oil capsules on a daily basis), and the remaining other two monkeys (#348 and #361) served as control and did not receive treatment. Animal #393 (treatment group), #361 (control group) and #348 (control group) died of SAIDS (opportunity infection) 3.5 months, 6 months, and 11 months later, respectively. Two animals (#374 and #381) survived. The necropsy revealed depletion and/or exhaustion of their lymphoid tissue. In the monkey #374, the peripheral CD4(+) T lymphocyte increased by 30% in the 6(th) month compared with the baseline level and then fluctuated. The plasma viral load gradually fell and reached about 1 log(10) in the treatment group, but remained stable in the control group. As shown by pathological examinations, the lymph node and spleen of monkeys #374 (treatment group) and #381 (treatment group) showed rehabilitation and reconstruction in the lymphatic tissue, thymus, nerve tissue of gyrus hippocampi, pituitary gland, pineal body, thyroid gland, adrenal gland, and ovary. In the control group, however, animals experienced depletion of lymph nodes, atrophy of spleen, disappearance of thymus, and other disorders in endocrine organs. Ganoderma lucidum preparation may have certain protective effect on the immune system, nervous system, and endocrine system of monkeys with SAIDS.

Reference values of clinical chemistry and hematology parameters in rhesus monkeys (Macaca mulatta)

Rhesus monkey models are valuable to the studies of human biology. Reference values for clinical chemistry and hematology parameters of rhesus monkeys are required for proper data interpretation. Whole blood was collected from 36 healthy Chinese rhesus monkeys (Macaca mulatta) of either sex, 3 to 5 yr old. Routine chemistry and hematology parameters, and some special coagulation parameters including thromboelastograph and activities of coagulation factors were tested. We presented here the baseline values of clinical chemistry and hematology parameters in normal Chinese rhesus monkeys. These data may provide valuable information for veterinarians and investigators using rhesus monkeys in experimental studies.

Rhesus angiotensin converting enzyme 2 supports entry of severe acute respiratory syndrome coronavirus in Chinese macaques

Angiotensin converting enzyme 2 (ACE2) is the receptor that severe acute respiratory syndrome coronavirus (SARS-CoV) utilizes for target cell entry and, therefore, plays an important role in SARS pathogenesis. Since Chinese rhesus (rh) macaques do not usually develop SARS after SARS-CoV infection, it has been suggested that rh-ACE2 probably does not support viral entry efficiently. To determine the role of rh-ACE2 in early lung pathogenesis in vivo, we studied eleven Chinese rhesus monkeys experimentally infected with a pathogenic SARS-CoV PUMC01 strain. Rh-ACE2 genes were amplified from all animals by reverse transcription polymerase chain reaction, and their function was studied in vitro using a pseudovirus entry assay. Many natural non-synonymous (NS) changes were found in rh-ACE2 genes. Compared to human (hu) ACE2, thirty-eight consensus NS changes were found in rh-ACE2. Since these changes do not interact with the receptor binding domain of SARS-CoV, rh-ACE2 in general is as effective as human homolog in supporting viral entry. Rh-ACE2, however, is more polymorphic than hu-ACE2. Additional sporadic NS substitutions in clone Rh11-7 reduced the level of rh-ACE2 protein expression and did not support viral entry effectively. Further mutagenesis analysis showed that a natural mutation Y217N dramatically alters ACE2 expression and entry efficiency. Moreover, introduction of the Y217N mutation into hu-ACE2 caused the down-regulation of expression and reduced viral entry efficiency. These results indicate that the Y217N mutation plays a role in modulating SARS-CoV infection. Our results provide insights for understanding the role of rh-ACE2 in SARS lung pathogenesis in a non-human primate model.

Establishment of AIDS animal model with SIVmac239 infected Chinese rhesus monkey

In the present research, two Chinese rhesus monkeys were inoculated intravenously with 5000 TCID50 of SIVmac239. The changes in the numbers of CD4+ T lymphocyte in peripheral blood, plasma viral loads, proviral DNA and humoral antibodies against virus were periodically monitored during 121 days. At the early stage of infection, proviral DNA had been detected in PBMCs, and infectious SIVmac239 virus had been isolated from PBMCs. At the same period, the numbers of CD4+ T lymphocytes were significantly decreased, and maintained at low level during the 121-day period of infection. Plasma viral loads reached the peak at week 2 post-inoculation and kept at a steady state subsequently. Moreover, antibodies against viral proteins were detected from plasma. All the results showed that the two Chinese rhesus monkeys had been infected with SIVmac239 successfully. This animal model can be applied for further AIDS researches.

Heterologous MVA-S prime Ad5-S boost regimen induces high and persistent levels of neutralizing antibody response against SARS coronavirus

Severe acute respiratory syndrome (SARS) is caused by a novel coronavirus (CoV), SARS-CoV. In previous studies, we showed that a SARS-CoV spike (S) glycoprotein-based modified vaccinia Ankara (MVA-S) vaccine could induce strong neutralizing antibody (Nab) response which might have played a critical role in protecting Chinese rhesus monkeys from the pathogenic viral challenge. To date, however, it remains unknown what the minimal level of Nab is required to achieve sterile immunity in humans. It is therefore important to explore techniques to maximize the level of Nab response in vivo. Here, we evaluate various vaccination regimens using combinations of DNA-S, MVA-S, and adenovirus type 5 (Ad5-S) vaccines. We show that in vaccinated mice and rabbits, a heterologous MVA-S prime with Ad5-S boost regimen induces the highest and most persistent level of Nab response when compared with other combinations. Interestingly, the initial level of Nab after prime does not necessarily predict the magnitude of the secondary response after the boost. Thus, our data provides a promising optimal regimen for vaccine development in humans against SARS-CoV infection.

Chinese Rhesus and Cynomolgus Macaques in HIV Vaccine and Pathogenesis Research

The development of an effective, prophylactic vaccine for HIV is a public health priority. Nonhuman primate models of AIDS are an instrumental component of HIV vaccine and pathogenesis research. Rhesus macaques of Indian origin are by far the most widely used species in vaccine research. The demand for these animals is intense, threatening their future availability. Do other macaques, such as non-Indian rhesus macaques and cynomolgus macaques, represent a viable alternative? In this perspective, the potential advantages and pitfalls of performing HIV vaccine research in non-Indian rhesus or cynomolgus macaques is examined.

Susceptibility of Chinese rhesus monkeys to SIV infection

The use of China-derived monkeys in AIDS research has been limited by reports of reduced susceptibility to SIV. We performed a serial passage of SIV in Chinese macaques, which resulted in a viral stock capable of inducing simian AIDS and high levels of replication in these animals. Similar to HIV in humans, SIV pathogenesis in non-human primates is not limited by geographical origin. Chinese macaques are useful in pathogenesis, vaccine, and therapeutic studies in AIDS.