ACE2 and TMPRSS2 variation in savanna monkeys (Chlorocebus spp.): Potential risk for zoonotic/anthroponotic transmission of SARS-CoV-2 and a potential model for functional studies.

The COVID-19 pandemic, caused by the coronavirus SARS-CoV-2, has devastated health infrastructure around the world. Both ACE2 (an entry receptor) and TMPRSS2 (used by the virus for spike protein priming) are key proteins to SARS-CoV-2 cell entry, enabling progression to COVID-19 in humans. Comparative genomic research into critical ACE2 binding sites, associated with the spike receptor binding domain, has suggested that African and Asian primates may also be susceptible to disease from SARS-CoV-2 infection. Savanna monkeys (Chlorocebus spp.) are a widespread non-human primate with well-established potential as a bi-directional zoonotic/anthroponotic agent due to high levels of human interaction throughout their range in sub-Saharan Africa and the Caribbean. To characterize potential functional variation in savanna monkey ACE2 and TMPRSS2, we inspected recently published genomic data from 245 savanna monkeys, including 163 wild monkeys from Africa and the Caribbean and 82 captive monkeys from the Vervet Research Colony (VRC). We found several missense variants. One missense variant in ACE2 (X:14,077,550; Asp30Gly), common in Ch. sabaeus, causes a change in amino acid residue that has been inferred to reduce binding efficiency of SARS-CoV-2, suggesting potentially reduced susceptibility. The remaining populations appear as susceptible as humans, based on these criteria for receptor usage. All missense variants observed in wild Ch. sabaeus populations are also present in the VRC, along with two splice acceptor variants (at X:14,065,076) not observed in the wild sample that are potentially disruptive to ACE2 function. The presence of these variants in the VRC suggests a promising model for SARS-CoV-2 infection and vaccine and therapy development. In keeping with a One Health approach, characterizing actual susceptibility and potential for bi-directional zoonotic/anthroponotic transfer in savanna monkey populations may be an important consideration for controlling COVID-19 epidemics in communities with frequent human/non-human primate interactions that, in many cases, may have limited health infrastructure.

Social history and exposure to pathogen signals modulate social status effects on gene regulation in rhesus macaques.

Social experience is an important predictor of disease susceptibility and survival in humans and other social mammals. Chronic social stress is thought to generate a proinflammatory state characterized by elevated antibacterial defenses and reduced investment in antiviral defense. Here we manipulated long-term social status in female rhesus macaques to show that social subordination alters the gene expression response to ex vivo bacterial and viral challenge. As predicted by current models, bacterial lipopolysaccharide polarizes the immune response such that low status corresponds to higher expression of genes in NF-κB-dependent proinflammatory pathways and lower expression of genes involved in the antiviral response and type I IFN signaling. Counter to predictions, however, low status drives more exaggerated expression of both NF-κB- and IFN-associated genes after cells are exposed to the viral mimic Gardiquimod. Status-driven gene expression patterns are linked not only to social status at the time of sampling, but also to social history (i.e., past social status), especially in unstimulated cells. However, for a subset of genes, we observed interaction effects in which females who fell in rank were more strongly affected by current social status than those who climbed the social hierarchy. Taken together, our results indicate that the effects of social status on immune cell gene expression depend on pathogen exposure, pathogen type, and social history-in support of social experience-mediated biological embedding in adulthood, even in the conventionally memory-less innate immune system.

Apicoplast phylogeny reveals the position of Plasmodium vivax basal to the Asian primate malaria parasite clade.

The malaria parasite species, Plasmodium vivax infects not only humans, but also African apes. Human specific P. vivax has evolved from a single ancestor that originated from a parasite of African apes. Although previous studies have proposed phylogenetic trees positioning P. vivax (the common ancestor of human and African ape P. vivax) within the assemblages of Asian primate parasites, its position has not yet been robustly confirmed. We determined nearly complete apicoplast genome sequences from seven Asian primate parasites, Plasmodium cynomolgi (strains Ceylonensis and Berok), P. knowlesi P. fragile, P. fieldi, P. simiovale, P. hylobati, P. inui, and an African primate parasite, P. gonderi, that infects African guenon. Phylogenetic relationships of the Plasmodium species were analyzed using newly and previously determined apicoplast genome sequences. Multigene maximum likelihood analysis of 30 protein coding genes did not position P. vivax within the Asian primate parasite clade but positioned it basal to the clade, after the branching of an African guenon parasite, P. gonderi. The result does not contradict with the emerging notion that P. vivax phylogenetically originated from Africa. The result is also supported by phylogenetic analyses performed using massive nuclear genome data of seven primate Plasmodium species.

MLH1-rheMac hereditary nonpolyposis colorectal cancer syndrome in rhesus macaques.

Over the past two decades, 33 cases of colonic adenocarcinomas have been diagnosed in rhesus macaques (Macaca mulatta) at the nonhuman primate colony of the Keeling Center for Comparative Medicine and Research at The University of Texas MD Anderson Cancer Center. The distinctive feature in these cases, based on PET/computed tomography (CT) imaging, was the presence of two or three tumor lesions in different locations, including proximal to the ileocecal juncture, proximal to the hepatic flexure, and/or in the sigmoid colon. These colon carcinoma lesions selectively accumulated [18F]fluorodeoxyglucose ([18F]FDG) and [18F]fluoroacetate ([18F]FACE) at high levels, reflecting elevated carbohydrate and fatty acid metabolism in these tumors. In contrast, the accumulation of [18F]fluorothymidine ([18F]FLT) was less significant, reflecting slow proliferative activity in these tumors. The diagnoses of colon carcinomas were confirmed by endoscopy. The expression of MLH1, MSH2, and MSH6 proteins and the degree of microsatellite instability (MSI) was assessed in colon carcinomas. The loss of MLH1 protein expression was observed in all tumors and was associated with a deletion mutation in the MLH1 promoter region and/or multiple single-nucleotide polymorphism (SNP) mutations in the MLH1 gene. All tumors exhibited various degrees of MSI. The pedigree analysis of this rhesus macaque population revealed several clusters of affected animals related to each other over several generations, suggesting an autosomal dominant transmission of susceptibility for colon cancer. The newly discovered hereditary nonpolyposis colorectal cancer syndrome in rhesus macaques, termed MLH1-rheMac, may serve as a model for development of novel approaches to diagnosis and therapy of Lynch syndrome in humans.

Characterization of the immune response in ganglia after primary simian varicella virus infection.

Primary simian varicella virus (SVV) infection in non-human primates causes varicella, after which the virus becomes latent in ganglionic neurons and reactivates to cause zoster. The host response in ganglia during establishment of latency is ill-defined. Ganglia from five African green monkeys (AGMs) obtained at 9, 13, and 20 days post-intratracheal SVV inoculation (dpi) were analyzed by ex vivo flow cytometry, immunohistochemistry, and in situ hybridization. Ganglia at 13 and 20 dpi exhibited mild inflammation. Immune infiltrates consisted mostly of CD8(dim) and CD8(bright) memory T cells, some of which expressed granzyme B, and fewer CD11c(+) and CD68(+) cells. Chemoattractant CXCL10 transcripts were expressed in neurons and infiltrating inflammatory cells but did not co-localize with SVV open reading frame 63 (ORF63) RNA expression. Satellite glial cells expressed increased levels of activation markers CD68 and MHC class II at 13 and 20 dpi compared to those at 9 dpi. Overall, local immune responses emerged as viral DNA load in ganglia declined, suggesting that intra-ganglionic immunity contributes to restricting SVV replication.

Down-modulation of primate lentiviral receptors by Nef proteins of simian immunodeficiency virus (SIV) of chimpanzees (SIVcpz) and related SIVs: implication for the evolutionary event at the emergence of SIVcpz.

It has been estimated that human immunodeficiency virus type 1 originated from the zoonotic transmission of simian immunodeficiency virus (SIV) of chimpanzees, SIVcpz, and that SIVcpz emerged by the recombination of two lineages of SIVs in Old World monkeys (SIVgsn/mon/mus in guenons and SIVrcm in red-capped mangabeys) and SIVcpz Nef is most closely related to SIVrcm Nef. These observations suggest that SIVrcm Nef had an advantage over SIVgsn/mon/mus during the evolution of SIVcpz in chimpanzees, although this advantage remains uncertain. Nef is a multifunctional protein which downregulates CD4 and coreceptor proteins from the surface of infected cells, presumably to limit superinfection. To assess the possibility that SIVrcm Nef was selected by its superior ability to downregulate viral entry receptors in chimpanzees, we compared its ability to down-modulate viral receptor proteins from humans, chimpanzees and red-capped mangabeys with Nef proteins from eight other different strains of SIVs. Surprisingly, the ability of SIVrcm Nef to downregulate CCR5, CCR2B and CXCR6 was comparable to or lower than SIVgsn/mon/mus Nef, indicating that ability to down-modulate chemokine receptors was not the selective pressure. However, SIVrcm Nef significantly downregulates chimpanzee CD4 over SIVgsn/mon/mus Nefs. Our findings suggest the possibility that the selection of SIVrcm Nef by ancestral SIVcpz is due to its superior capacity to down-modulate chimpanzees CD4 rather than coreceptor proteins.

A critical Sp1 element in the rhesus rhadinovirus (RRV) Rta promoter confers high-level activity that correlates with cellular permissivity for viral replication.

KSHV establishes characteristic latent infections in vitro, while RRV, a related macaque rhadinovirus, establishes characteristic permissive infections with virus replication. We identified cells that are not permissive for RRV replication and recapitulate the latent KSHV infection and reactivation processes. The RRV replication and transactivator (Rta) promoter was characterized in permissive and non-permissive cells and compared to the KSHV Rta promoter. Both promoters contained a critical Sp1 element, had equivalent activities in different cell types, and were inhibited by LANA. RRV and KSHV infections were non-permissive in cells with low Rta promoter activity. While RRV infections were permissive in cells with high basal promoter activity, KSHV infections remained non-permissive. Our studies suggest that RRV lacks the Rta-inducible LANA promoter that is responsible for LANA inhibition of the KSHV Rta promoter and induction of latency during KSHV infection. Instead, the outcome of RRV infection is determined by host factors, such as Sp1.

Role of trim5α in the suppression of cross-species transmission and its defence against human immunodeficiency virus.

Acquired Immunodeficiency Syndrome (AIDS) was discovered 30 years ago and was followed by the identification and characterization of its causative agent, Human Immunodeficiency Virus (HIV). Increasing spread of retroviral infections has impelled science to understand the evolution of retroviruses from primates to humans. In the course of evolution, host cells have developed intracellular proteins to counteract the transforming viral defence system. Such inhibitory endogenous intracellular proteins are known as restriction factors. Tripartite motif protein isoform 5 alpha (TRIM5α), Apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like (APOBEC), and Tetherin proteins are few important restriction factors that have been extensively studied. Several evidences have conveyed information regarding specific adaptations occurring in HIV-1 and its relatives to inhibit these host defenses; making the study more interesting. The characteristic potential of restriction factors to restrict the replication of retroviruses was enticing when studies were found that HIV-1 virus cannot infect nonhuman primate species. This review emphasizes on TRIM5α as a restriction factor and its significance in the evolution of retroviruses. It also accentuates the role of polymorphism within the regions of TRIM5α in both human and primate species that eventually affect the cross-species transmission of immunodeficiency viruses.

Species specificity of protein kinase r antagonism by cytomegalovirus TRS1 genes.

The host antiviral protein kinase R (PKR) has rapidly evolved during primate evolution, likely in response to challenges posed by many different viral antagonists, such as the TRS1 gene of cytomegaloviruses (CMVs). In turn, viral antagonists have adapted to changes in PKR. As a result of this "arms race," modern TRS1 alleles in CMVs may function differently in cells derived from alternative species. We have previously shown that human CMV TRS1 (HuTRS1) blocks the PKR pathway and rescues replication of a vaccinia virus mutant lacking its major PKR antagonist in human cells. We now demonstrate that HuTRS1 does not have these activities in Old World monkey cells. Conversely, the rhesus cytomegalovirus homologue of HuTRS1 (RhTRS1) fulfills these functions in African green monkey cells, but not rhesus or human cells. Both TRS1 proteins bind to double-stranded RNA and, in the cell types in which they can rescue VVΔE3L replication, they also bind to PKR and prevent phosphorylation of the α-subunit of eukaryotic initiation factor 2. However, while HuTRS1 binds to inactive human PKR and prevents its autophosphorylation, RhTRS1 binds to phosphorylated African green monkey PKR. These studies reveal that evolutionary adaptations in this critical host defense protein have altered its binding interface in a way that has resulted in a qualitatively altered mechanism of PKR antagonism by viral TRS1 alleles from different CMVs. These results suggest that PKR antagonism is likely one of the factors that contributes to species specificity of cytomegalovirus replication.

Viral interferon regulatory factors decrease the induction of type I and type II interferon during rhesus macaque rhadinovirus infection.

Kaposi's sarcoma-associated herpesvirus and rhesus macaque rhadinovirus (RRV), two closely related gammaherpesviruses, are unique in their expression of viral homologs of cellular interferon regulatory factors (IRFs), termed viral IRFs (vIRFs). To assess the role of vIRFs during de novo infection, we have utilized the bacterial artificial chromosome clone of wild-type RRV(17577) (WT(BAC) RRV) to generate a recombinant virus with all 8 of the vIRFs deleted (vIRF-ko RRV). The infection of primary rhesus fibroblasts and peripheral blood mononuclear cells (PBMCs) with vIRF-ko RRV resulted in earlier and increased induction of type I interferon (IFN) (IFN-α/ß) and type II IFN (IFN-γ). Additionally, plasmacytoid dendritic cells maintained higher levels of IFN-α production in PBMC cultures infected with vIRF-ko RRV than in cultures infected with WT(BAC) RRV. Moreover, the nuclear accumulation of phosphorylated IRF-3, which is necessary for the induction of type I IFN, was also inhibited following WT(BAC) RRV infection. These findings demonstrate that during de novo RRV infection, vIRFs are inhibiting the induction of IFN at the transcriptional level, and one potential mechanism for this is the disruption of the activation and localization of IRF-3.

H-ras consensus sequence and mutations in primary hepatocellular carcinomas of lemurs and lorises.

The authors have determined a consensus sequence for exons 1 and 2 of H-ras from captive lemurs and lorises and evaluated samples of nonneoplastic liver and hepatocellular carcinomas (HCC) from affected animals for mutations in these exons. Frozen liver samples were collected from 20 animals representing 9 different species with a sex distribution of 10 males and 10 females. A total of 26 liver samples, including 11 normal livers, 9 HCC, and 6 samples from nonneoplastic regions of liver from animals with HCC, were evaluated. This is the first report of the consensus sequence for exons 1 and 2 of H-ras in prosimians, and the authors have determined that it is identical to that of human H-ras and differs only slightly from the chimpanzee sequence. Point mutations were identified in 6 of the 9 HCC samples examined with codons 7, 22, 32, 56, 61, 84, and 96 affected. Two carcinomas had double mutations, and one tumor had triple mutations. One HCC had a mutation in codon 61, which is identical to a recognized affected codon for an H-ras "hot spot" in rodent neoplasia that has also been reported in human tumors. Although not statistically different, metastasis occurred in 5 of 6 HCC with H-ras mutation and only 1 of 3 HCC without mutations. There were 4 silent mutations that did not contain changes in the encoded amino acids, 2 of which were found in nonneoplastic regions of tumor-bearing liver.

Torque teno virus (TTV) is prevalent in Brazilian non-human primates and chickens (Gallus gallus domesticus) / Torque teno virus (TTV) es prevalente en primates no humanos brasileños y pollos (Gallus gallus domesticus)

Torque Teno virus (TTV) is an infectious agent of worldwide distribution isolated by the first time as the agent of an acute post-transfusion hepatitis in a patient in Japan. It has been classified into a new floating genus called Anellovirus. Recent studies showed that TTV can also be identified in serum specimens obtained from domesticated farm animals and from non-human primates. To better understand the relationship between TTV and their hosts, a study to detect virus in the serum and whole blood of Brazilian non-human primates and in the plasm of chickens was performed by applying the PCR-UTR-A technique, followed by a genomic sequence and phylogenetic analysis. By nested-PCR-UTR, the DNA of TTV was detected in sera from 4 (5.3 percent) of 75 Cebus apella, 2 (40 percent) of 5 Alouatafusca, 1 (20 percent) of 5 Alouata caraya, 1 (5.2 percent) of 19 Callithrixpenicilata, 1 (4 percent) of 25 Callithrixjacchus, 1 (20 percent) of 5 Saimiri sciureus and 1 (25 percent) of 4 Leontopithecus chrysomelas. Phylogenetic analysis revealed that sequences detected in 8 samples clustered with TTV sequences So-TTV2 (Sagüínus oedipus) and At-TTV3 (Aotes Trivirgatus). Three sequences showed similarity with a human Torque Teno Minivirus (TLMV). TTV ORF2 DNA was detected in one sera sample and one whole blood sample of non-human primates and in one plasm sample of chicken. Phylogenetic analysis revealed that the sequences amplified by the ORF2 region show no difference between human, non-human primates and chicken. This is the first report of TTV in Brazilian new world non-human primates and chicken.

Torque Teno virus (TTV) es una agente infeccioso de distribución mundial, aislado por primera vez como el agente de una hepatitis aguda posterior a la transfusión de un paciente en Japón. Se ha clasificado en un nuevo género flotante llamado Anellovirus. Recientes estudios han demostrado que TTV también puede ser identificado en el suero de especímenes obtenidos desde granjas de animales domésticos y desde primates no humanos. Para entender mejor la relación entre la TTV y sus huéspedes, fue realizado un estudio para detectar el virus en el suero y la sangre de primates no humanos brasileños y en el plasma de pollos mediante la aplicación de la técnica PCR-UTR-A, seguida de una secuencia genómica y análisis filogenético. Por medio de PCR-UTR-anidado, el ADN de TTV fue detectado en sueros de 4 de 75 (5,3 por ciento)Cebus apella, 2 de 5 (40 por ciento) Alouata fusca, 1 de 5 (20 por ciento) de Alouata caraya, 1 de 19 (5,2 por ciento) de Callithrixpenicilata, 1 de 25 (4 por ciento) Callithrixjacchus, 1 de 5 (20 por ciento) de Saimiri sciureus y 1 de 4 (25 por ciento) de Leontopithecus chrysomelas. El análisis filogenético reveló secuencias detectadas en 8 muestras agrupadas con TTV secuencias So-TTV2 (Sagüínus oedipus) y At-TTV3 (Aotes Trivirgatus). Tres secuencias mostraron similitud con el Torque Teno Minivirus humano (TLMV). Fue detectado TTV ORF2 ADN en una muestra de suero y una muestra de sangre de primates no-humanos y en una muestra de plasma de pollo. El análisis filogenético reveló que las secuencias amplificadas por la región ORF2 no muestran ninguna diferencia entre humanos, primates no humanos y pollos. Este es el primer informe de nuevos TTV en primates-no humanos brasileños y en pollos.

Research of torque teno virus (TTV) in serum and total blood of Brazilian non-human primates and in chicken plasma (Gallus gallus domesticus) by the PCR N22 region / Investigación de Torque teno virus (TTV) en suero y sangre de primates no humanos brasileños y en plasma de pollo (Gallus gallus domesticus) por PCR en la region N22

Torque teno virus (TTV) is a recently discovered DNA virus that was originally isolated from a Japanese patient (initials, TT) with post-transfusion hepatitis of unknown aetiology. TTV is an circular DNA virus classified recently together with related Torque teño minivirus, into a new genus called Anellovirus. Infection TTV has been detected in a range of non-human primates as well as domestic animals. The purpose of this study was to search TTV in the serum and total blood of Brazilian monkeys and in plasma of domestic chickens by seminested PCR of coding region (N22), followed by a genomic sequence and phylogenetic analysis. No serum sample was amplified. TTV DNA was detected in total blood from 3 (4 percent) out of 75 brown-capuchin (Cebus apella) and from 1 (25 percent) out of 4 golden-headed lion-tamarin (Leontopithecus chrysomelas). Phylogenetic analysis revealed that one sample showed similarity with one sequence of the cotton top tamarin (Saguinus oedipus) (So-TTV2) and with one of the douroucoulis (ão tes trivirgatus) (At-TTV3). Two samples showed similarity with a human Torque Teño Mini Virus (TLMV). The other sample clustered with one sequence of the chimpanzee (Pt-TTV6) and with the human TTV strain TA278. The plasma chicken samples tested were all negative. The amino acid sequences reported in this study are the first obtained in Brazil from total blood of non-human primates naturally infected by TTV.

Torque teno virus (TTV) es un virus de ADN recientemente descubierto que fue inicialmente aislado de un paciente japonés (iniciales TT) después de la transfusión de hepatitis de etiología desconocida. TTV es un virus de ADN circular recientemente clasificado junto con los torque teno minivirus, en un nuevo género llamado Anellovirus. La infección de TTV se ha detectado en una serie de primates no humanos, así como animales domésticos. El objetivo de este estudio fue buscar TTV en el suero y sangre total de monos de Brasil y en el plasma de pollos domésticos, por seminested PCR de la región de codificación (N22), seguido de una secuencia genómica y el análisis filogenético. Las muestras que no eran suero fueron amplificadas. TTV DNA se detectó en sangre total de 3 (4 por ciento) de un total de 75 capuchinos de cabeza dura (Cebus apella) y de 1 (25 por ciento) de un total de 4 tití- león de cabeza dorada (Leontopithecus chrysomelas). El análisis filogenético demostró que una muestra presentaba similitud con una secuencia de Saguinus Edipo (So-TTV2) y con una de Aotes trivirgatus (A-TTV3). Dos muestras mostraron similitud con un torque teno mini virus (TLMV) humano. La otra muestra agrupada con una secuencia de los chimpancés (PT-TTV6) y con el TTV humanos cepa TA278. El análisis de las muestras de plasma de pollo fueron negativas Las secuencias de aminoácidos que se reportan en este estudio son las primeras obtenidas en Brasil de sangre de primates no humanos infectados naturalmente por TTV.

Role of Nef in primate lentiviral immunopathogenesis.

More than a decade ago it was established that intact nef genes are critical for efficient viral persistence and greatly accelerate disease progression in SIVmac-infected rhesus macaques and in HIV-1-infected humans. Subsequent studies established a striking number of Nef functions that evidently contribute to the maintenance of high viral loads associated with the development of immunodeficiency in the 'evolutionary-recent' human and the experimental macaque hosts. Recent data show that many Nef activities are conserved across different lineages of HIV and SIV. However, some differences also exist. For example, Nef alleles from most SIVs that do not cause disease in their natural monkey hosts, but not those of HIV-1 and its simian precursors, down-modulate TCR-CD3 to suppress T cell activation and programmed death. This evolutionary loss of a specific Nef function may contribute to the high virulence of HIV-1 in humans.

Long-term clinical improvement in MPTP-lesioned primates after gene therapy with AAV-hAADC.

Dopamine, the major neurotransmitter depleted in Parkinson disease, can be synthesized and regulated in vivo with a combination of intrastriatal AAV-hAADC gene therapy and administration of the dopamine precursor l-Dopa. When tested in MPTP-lesioned monkeys, this approach resulted in long-term improvement in clinical rating scores, significantly lowered l-Dopa requirements, and a reduction in l-Dopa-induced side effects. Positron emission tomography with [(18)F]FMT confirmed persistent AADC activity, demonstrating for the first time that infusion of AAV vector into primate brain results in at least 6 years of transgene expression. AAV-hAADC restores the ability of the striatum to convert l-Dopa into dopamine efficiently. Introduction of this therapy into the clinic holds promise for Parkinson patients experiencing the motor complications that result from escalating l-Dopa requirements against a background of disease progression.

The B30.2(SPRY) domain of the retroviral restriction factor TRIM5alpha exhibits lineage-specific length and sequence variation in primates.

Tripartite motif (TRIM) proteins are composed of RING, B-box 2, and coiled coil domains. Some TRIM proteins, such as TRIM5alpha, also possess a carboxy-terminal B30.2(SPRY) domain and localize to cytoplasmic bodies. TRIM5alpha has recently been shown to mediate innate intracellular resistance to retroviruses, an activity dependent on the integrity of the B30.2 domain, in particular primate species. An examination of the sequences of several TRIM proteins related to TRIM5 revealed the existence of four variable regions (v1, v2, v3, and v4) in the B30.2 domain. Species-specific variation in TRIM5alpha was analyzed by amplifying, cloning, and sequencing nonhuman primate TRIM5 orthologs. Lineage-specific expansion and sequential duplication occurred in the TRIM5alpha B30.2 v1 region in Old World primates and in v3 in New World monkeys. We observed substitution patterns indicative of selection bordering these particular B30.2 domain variable elements. These results suggest that occasional, complex changes were incorporated into the TRIM5alpha B30.2 domain at discrete time points during the evolution of primates. Some of these time points correspond to periods during which primates were exposed to retroviral infections, based on the appearance of particular endogenous retroviruses in primate genomes. The results are consistent with a role for TRIM5alpha in innate immunity against retroviruses.

Parasites and the evolutionary diversification of primate clades.

Coevolutionary interactions such as those between hosts and parasites have been regarded as an underlying cause of evolutionary diversification, but evidence from natural populations is limited. Among primates and other mammalian groups, measures of host diversification rates vary widely among lineages, but comparative studies have not yet identified a reliable explanation for this variation. In this study, we used a comprehensive data set of disease-causing organisms from free-living primates to illustrate how phylogenetic comparative methods can be used to examine mammalian lineage diversity in relation to parasite species richness. Our results provide evidence that the phylogenetic diversity of primate clades is correlated positively with the number of parasite species harbored by each host and that this pattern is largely independent of other host traits that have been shown to influence diversification rates and parasite species richness in primates. We investigated two possible mechanisms that could explain this association, namely that parasites themselves drive host evolutionary diversification through processes linked with sexual selection and that host shifts or host sharing increases parasite species richness among diverse primate clades. Neither parasite species richness nor host diversification is related to measures of sexual selection in primates. Further, we found only partial evidence that more rapidly diversifying host lineages produced increased opportunities for host sharing or host shifting by parasites through mechanisms involving species' geographic range overlap. Thus, our analyses provide evidence for an important link between the evolutionary diversification of primates and the richness of their parasite communities, but other mechanisms, particularly those related to reciprocal selection or coextinction of hosts and parasites, require further investigation.

Conserved CTL epitopes shared between HIV-infected human long-term survivors and chimpanzees.

Certain HIV-1 infected humans that do not progress to AIDS have been documented to share particular MHC class I alleles that appear to correlate with long-term survival. HIV-1-infected chimpanzees are relatively resistant to progression to AIDS. Out of a group of 10 chimpanzees with CTL activity and nonprogressive HIV-1 infection, 2 animals with prominent cytolytic CD3+CD8+ T cell responses to HIV-1 Ags were studied in detail. Characterization of these CTL revealed that they contained the granzymes A and B, T cell intracellular Ag-1, and perforin and induced calcium-dependent cytolysis that correlated with the presence of apoptotic nuclei in target cells. These CTL responses were directed against two gagpeptides, which were found to be identical to previously described epitopes recognized in the context of HLA-B27 and HLA-B57 molecules. The latter two restriction elements occur with increased frequency in human long-term survivor cohorts. Phylogenetic comparisons revealed that the chimpanzee restriction elements, Patr-B*02and -B*03, described here do not show any obvious similarity with the HLA-B*27 and -B*57 alleles, suggesting that CTL responses to HIV-1 in distinct primate species may be controlled by different types of HLA-B-like molecules. The CTL responses in these two chimpanzees are directed, however, against highly conserved epitopes mapping across the majority of HIV-1 clades.

Sequence variation and size ranges of CAG repeats in the Machado-Joseph disease, spinocerebellar ataxia type 1 and androgen receptor genes.

A subgroup of trinucleotide repeat diseases result from abnormal expansions of CAG repeats which are translated into polyglutamine stretches. As yet there is little understanding of how the polyglutamines function either normally, or when expanded. We have investigated these sequences in the Machado-Joseph disease, androgen receptor and spinocerebellar ataxia type 1 genes in humans and other primates. None of the 748 normal chromosomes that were examined had more than 34 uninterrupted glutamine codons in the Machado-Joseph disease gene. Similarly, no normal alleles with more than 39 uninterrupted glutamine codons have been reported for the other disease genes associated with polyglutamine expansions. Sequence analyses of the repeats in primates revealed shorter polyglutamine stretches in some of the non-human primates at all three loci and marked diversions from the expected polyglutamines in the orang-utan Machado-Joseph gene and in the marmoset spinocerebellar ataxia type 1 gene. These data suggest that conservation of these polyglutamine stretches may not always be necessary for normal gene function.