Allogeneic immunity clears latent virus following allogeneic stem cell transplantation in SIV-infected ART-suppressed macaques.

Allogeneic hematopoietic stem cell transplantation (alloHSCT) from donors lacking C-C chemokine receptor 5 (CCR5Δ32/Δ32) can cure HIV, yet mechanisms remain speculative. To define how alloHSCT mediates HIV cure, we performed MHC-matched alloHSCT in SIV+, anti-retroviral therapy (ART)-suppressed Mauritian cynomolgus macaques (MCMs) and demonstrated that allogeneic immunity was the major driver of reservoir clearance, occurring first in peripheral blood, then peripheral lymph nodes, and finally in mesenteric lymph nodes draining the gastrointestinal tract. While allogeneic immunity could extirpate the latent viral reservoir and did so in two alloHSCT-recipient MCMs that remained aviremic >2.5 years after stopping ART, in other cases, it was insufficient without protection of engrafting cells afforded by CCR5-deficiency, as CCR5-tropic virus spread to donor CD4+ T cells despite full ART suppression. These data demonstrate the individual contributions of allogeneic immunity and CCR5 deficiency to HIV cure and support defining targets of alloimmunity for curative strategies independent of HSCT.

Molecular and Phylogenetic Characterization of Novel Papillomaviruses Isolated from Oral and Anogenital Neoplasms of Japanese Macaques (Macaca fuscata).

Papillomaviruses (PVs) are a diverse group of host species-specific DNA viruses, etiologically linked with various benign and malignant neoplasms of cutaneous and mucosal epithelia. Here, we describe the detection and characterization of the first two PVs naturally infecting Japanese macaques (Macaca fuscata), including the determination of their etiological association(s) with the development of original neoplasms. The molecular and phylogenetic analyses were performed on complete genome sequences of Macaca fuscata PV types 1 (MfuPV1) and 2 (MfuPV2), which were completely sequenced in samples of a malignant oral tumor and benign anogenital neoplasm of Japanese macaques, respectively. Subsequently, two type-specific quantitative real-time PCRs were developed to estimate viral loads of MfuPV1 and MfuPV2 and to evaluate their etiological roles. The in silico molecular analyses revealed that both viral genomes encode characteristic PV proteins with conserved functional domains and have a non-coding genomic region with regulatory sequences to regulate and complete the viral life cycle. However, additional experimental evidence is needed to finally confirm the presence and biological functionality of the molecular features of both novel PVs. While MfuPV1, together with PVs identified in other macaques, is classified into the Alphapapillomavirus (Alpha-PV) species 12, MfuPV2 is most likely a representative of the novel viral species within the Alpha-PV genus. Their relatively high viral loads suggest that both PVs are etiologically linked with the development of the original neoplasms.

Urothelial carcinoma in the urinary bladder of a Japanese macaque (Macaca fuscata).

Tumors of urinary origin are infrequently reported in non-human primates. Urothelial carcinoma involving the urinary bladder was diagnosed in an adult female Japanese macaque that extended transmurally to the uterus and cervix. To our knowledge, this is the first report of a primary cystic urothelial carcinoma in a Japanese macaque.

A neonatal nonhuman primate model of gestational Zika virus infection with evidence of microencephaly, seizures and cardiomyopathy.

Zika virus infection during pregnancy is associated with miscarriage and with a broad spectrum of fetal and neonatal developmental abnormalities collectively known as congenital Zika syndrome (CZS). Symptomology of CZS includes malformations of the brain and skull, neurodevelopmental delay, seizures, joint contractures, hearing loss and visual impairment. Previous studies of Zika virus in pregnant rhesus macaques (Macaca mulatta) have described injury to the developing fetus and pregnancy loss, but neonatal outcomes following fetal Zika virus exposure have yet to be characterized in nonhuman primates. Herein we describe the presentation of rhesus macaque neonates with a spectrum of clinical outcomes, including one infant with CZS-like symptoms including cardiomyopathy, motor delay and seizure activity following maternal infection with Zika virus during the first trimester of pregnancy. Further characterization of this neonatal nonhuman primate model of gestational Zika virus infection will provide opportunities to evaluate the efficacy of pre- and postnatal therapeutics for gestational Zika virus infection and CZS.

Bardet-Biedl Syndrome in rhesus macaques: A nonhuman primate model of retinitis pigmentosa.

The development of therapies for retinal disorders is hampered by a lack of appropriate animal models. Higher nonhuman primates are the only animals with retinal structure similar to humans, including the presence of a macula and fovea. However, few nonhuman primate models of genetic retinal disease are known. We identified a lineage of rhesus macaques with a frameshift mutation in exon 3 of the BBS7 gene c.160delG (p.Ala54fs) that is predicted to produce a non-functional protein. In humans, mutations in this and other BBS genes cause Bardet-Biedl syndrome, a ciliopathy and a syndromic form of retinitis pigmentosa generally occurring in conjunction with kidney dysfunction, polydactyly, obesity, and/or hypogonadism. Three full- or half-sibling monkeys homozygous for the BBS7 c.160delG variant, at ages 3.5, 4 and 6 years old, displayed a combination of severe photoreceptor degeneration and progressive kidney disease. In vivo retinal imaging revealed features of severe macular degeneration, including absence of photoreceptor layers, degeneration of the retinal pigment epithelium, and retinal vasculature atrophy. Electroretinography in the 3.5-year-old case demonstrated loss of scotopic and photopic a-waves and markedly reduced and delayed b-waves. Histological assessments in the 4- and 6-year-old cases confirmed profound loss of photoreceptors and inner retinal neurons across the posterior retina, with dramatic thinning and disorganization of all cell layers, abundant microglia, absent or displaced RPE cells, and significant gliosis in the subretinal space. Retinal structure, including presence of photoreceptors, was preserved only in the far periphery. Ultrasound imaging of the kidneys revealed deranged architecture, and renal histopathology identified distorted contours with depressed, fibrotic foci and firmly adhered renal capsules; renal failure occurred in the 6-year-old case. Magnetic resonance imaging obtained in one case revealed abnormally low total brain volume and unilateral ventricular enlargement. The one male had abnormally small testes at 4 years of age, but polydactyly and obesity were not observed. Thus, monkeys homozygous for the BBS7 c.160delG variant closely mirrored several key features of the human BBS syndrome. This finding represents the first identification of a naturally-occurring nonhuman primate model of BBS, and more broadly the first such model of retinitis pigmentosa and a ciliopathy with an associated genetic mutation. This important new preclinical model will provide the basis for better understanding of disease progression and for the testing of new therapeutic options, including gene and cell-based therapies, not only for BBS but also for multiple forms of photoreceptor degeneration.

Allogeneic stem cell transplantation in fully MHC-matched Mauritian cynomolgus macaques recapitulates diverse human clinical outcomes.

Allogeneic hematopoietic stem cell transplantation (HSCT) is a critically important therapy for hematological malignancies, inborn errors of metabolism, and immunodeficiency disorders, yet complications such as graft-vs.-host disease (GvHD) limit survival. Development of anti-GvHD therapies that do not adversely affect susceptibility to infection or graft-vs.-tumor immunity are hampered by the lack of a physiologically relevant, preclinical model of allogeneic HSCT. Here we show a spectrum of diverse clinical HSCT outcomes including primary and secondary graft failure, lethal GvHD, and stable, disease-free full donor engraftment using reduced intensity conditioning and mobilized peripheral blood HSCT in unrelated, fully MHC-matched Mauritian-origin cynomolgus macaques. Anti-GvHD prophylaxis of tacrolimus, post-transplant cyclophosphamide, and CD28 blockade induces multi-lineage, full donor chimerism and recipient-specific tolerance while maintaining pathogen-specific immunity. These results establish a new preclinical allogeneic HSCT model for evaluation of GvHD prophylaxis and next-generation HSCT-mediated therapies for solid organ tolerance, cure of non-malignant hematological disease, and HIV reservoir clearance.

Therapeutic administration of a recombinant human monoclonal antibody reduces the severity of chikungunya virus disease in rhesus macaques.

Chikungunya virus (CHIKV) is a mosquito-borne virus that causes a febrile syndrome in humans associated with acute and chronic debilitating joint and muscle pain. Currently no licensed vaccines or therapeutics are available to prevent or treat CHIKV infections. We recently isolated a panel of potently neutralizing human monoclonal antibodies (mAbs), one (4N12) of which exhibited prophylactic and post-exposure therapeutic activity against CHIKV in immunocompromised mice. Here, we describe the development of an engineered CHIKV mAb, designated SVIR001, that has similar antigen binding and neutralization profiles to its parent, 4N12. Because therapeutic administration of SVIR001 in immunocompetent mice significantly reduced viral load in joint tissues, we evaluated its efficacy in a rhesus macaque model of CHIKV infection. Rhesus macaques that were treated after infection with SVIR001 showed rapid elimination of viremia and less severe joint infiltration and disease compared to animals treated with SVIR002, an isotype control mAb. SVIR001 reduced viral burden at the site of infection and at distant sites and also diminished the numbers of activated innate immune cells and levels of pro-inflammatory cytokines and chemokines. SVIR001 therapy; however, did not substantively reduce the induction of CHIKV-specific B or T cell responses. Collectively, these results show promising therapeutic activity of a human anti-CHIKV mAb in rhesus macaques and provide proof-of-principle for its possible use in humans to treat active CHIKV infections.

Correction: Zika Virus infection of rhesus macaques leads to viral persistence in multiple tissues.

[This corrects the article DOI: 10.1371/journal.ppat.1006219.].

Zika Virus infection of rhesus macaques leads to viral persistence in multiple tissues.

Zika virus (ZIKV), an emerging flavivirus, has recently spread explosively through the Western hemisphere. In addition to symptoms including fever, rash, arthralgia, and conjunctivitis, ZIKV infection of pregnant women can cause microcephaly and other developmental abnormalities in the fetus. We report herein the results of ZIKV infection of adult rhesus macaques. Following subcutaneous infection, animals developed transient plasma viremia and viruria from 1-7 days post infection (dpi) that was accompanied by the development of a rash, fever and conjunctivitis. Animals produced a robust adaptive immune response to ZIKV, although systemic cytokine response was minimal. At 7 dpi, virus was detected in peripheral nervous tissue, multiple lymphoid tissues, joints, and the uterus of the necropsied animals. Notably, viral RNA persisted in neuronal, lymphoid and joint/muscle tissues and the male and female reproductive tissues through 28 to 35 dpi. The tropism and persistence of ZIKV in the peripheral nerves and reproductive tract may provide a mechanism of subsequent neuropathogenesis and sexual transmission.

Air sacculitis in three rhesus macaques (Macaca mulatta) and one Japanese macaque (M. fuscata).

Bacterial infection of the laryngeal air sacs (air sacculitis) is infrequently reported in nonhuman primates, where it leads to chronic respiratory disease. It is particularly uncommon in macaques; however, we report here suppurative air sacculitis with extension to adjacent cervical tissues in three rhesus macaques and one Japanese macaque. Staphylococcus aureus, Streptococcus sp., and an anaerobic bacterium were isolated.

Spontaneous nocardial brain abscess in a juvenile rhesus macaque (Macaca mulatta).

BACKGROUND: A juvenile rhesus macaque presented with blindness, ataxia, and head tilt. METHODS: Postmortem gross and microscopic examination, histochemical staining and bacterial culture were performed. RESULTS: Nocardia sp. was identified as the etiologic agent of a primary pneumonia with secondary cerebral abscessation. CONCLUSIONS: Nocardiosis should be a differential diagnosis for patients with neurologic disease.

A simian hemorrhagic fever virus isolate from persistently infected baboons efficiently induces hemorrhagic fever disease in Japanese macaques.

Simian hemorrhagic fever virus is an arterivirus that naturally infects species of African nonhuman primates causing acute or persistent asymptomatic infections. Although it was previously estimated that 1% of baboons are SHFV-positive, more than 10% of wild-caught and captive-bred baboons tested were SHFV positive and the infections persisted for more than 10 years with detectable virus in the blood (100-1000 genomes/ml). The sequences of two baboon SHFV isolates that were amplified by a single passage in primary macaque macrophages had a high degree of identity to each other as well as to the genome of SHFV-LVR, a laboratory strain isolated in the 1960s. Infection of Japanese macaques with 100PFU of a baboon isolate consistently produced high level viremia, pro-inflammatory cytokines, elevated tissue factor levels and clinical signs indicating coagulation defects. The baboon virus isolate provides a reliable BSL2 model of viral hemorrhagic fever disease in macaques.

Neutralizing polyclonal IgG present during acute infection prevents rapid disease onset in simian-human immunodeficiency virus SHIVSF162P3-infected infant rhesus macaques.

Simian-human immunodeficiency virus (SHIV) models for human immunodeficiency virus (HIV) infection have been widely used in passive studies with HIV neutralizing antibodies (NAbs) to test for protection against infection. However, because SHIV-infected adult macaques often rapidly control plasma viremia and any resulting pathogenesis is minor, the model has been unsuitable for studying the impact of antibodies on pathogenesis in infected animals. We found that SHIVSF162P3 infection in 1-month-old rhesus macaques not only results in high persistent plasma viremia but also leads to very rapid disease progression within 12 to 16 weeks. In this model, passive transfer of high doses of neutralizing IgG (SHIVIG) prevents infection. Here, we show that at lower doses, SHIVIG reduces both plasma and peripheral blood mononuclear cell (PBMC)-associated viremia and mitigates pathogenesis in infected animals. Moreover, production of endogenous NAbs correlated with lower set-point viremia and 100% survival of infected animals. New SHIV models are needed to investigate whether passively transferred antibodies or antibodies elicited by vaccination that fall short of providing sterilizing immunity impact disease progression or influence immune responses. The 1-month-old rhesus macaque SHIV model of infection provides a new tool to investigate the effects of antibodies on viral replication and clearance, mechanisms of B cell maintenance, and the induction of adaptive immunity in disease progression.

An outbreak of tularemia in a colony of outdoor-housed rhesus macaques (Macaca mulatta).

Since an epizootic and detection of clinical cases of tularemia (Francisella tularensis) in 1996 at the Oregon National Primate Research Center, only 8 cases were identified in the succeeding 13 y. However, within a period of 7 mo, primarily during Winter 2010, 6 rhesus macaques were confirmed positive for Francisella tularensis type B by the Centers for Disease Control and Prevention by culture and fluorescent antibody testing. All cases had similar gross pathologic findings, which included necrotizing splenitis and lymphadenitis. Recent colony management efforts have focused on minimizing nonhuman primate exposure to commonly observed reservoir species and controlling rodent access to corral-style housing. Strategies continue to evolve with regard to managing a large breeding colony of nonhuman primates in the presence of this threat.

Staphylococcus-induced urolithiasis in estrogen-treated ovariectomized nude mice.

Nine of 24 ovariectomized nude mice developed ulcerative skin lesions 28 d after implantation with human breast cancer cells and slow-release estrogen pellets. Aerobic culture of samples from the skin lesions yielded Staphylococcus intermedius. By day 45 postimplantation, all mice displayed ulcerative skin lesions, and 5 mice exhibited hunched posture, listless behavior, cyanosis, anorexia, and dehydration. This subset was euthanized but not necropsied. When additional animals became moribund, the investigator elected to end the study at day 51. At necropsy, all 20 but 1 had cystitis and urolithiasis, characterized by relatively large struvite stones and crystals that had filled the urinary bladders of the research animals and caused severe thickening of the bladder walls. Gram-positive cocci were observed microscopically in both the kidneys and bladders of the necropsied animals. Spontaneous urolithiasis has not previously been documented to occur in association with infection of female nude mice by S. intermedius.

High resolution radiographic and fine immunologic definition of TB disease progression in the rhesus macaque.

Mycobacterium tuberculosis infection in non-human primates parallels human tuberculosis, and provides a valuable vaccine evaluation model. However, this model is limited by the availability of real-time, non-invasive information regarding disease progression. Consequently, we have combined computed tomography scanning with enumeration of antigen-specific T cell responses. Four rhesus monkeys were infected with M. tuberculosis strain H37Rv (1000 cfu) in the right lower lobe via a bronchoscope. All uniformly developed progressive tuberculosis, and required euthanasia at 12 weeks. Computed tomography scanning provided detailed real-time imaging of disease progression. At necropsy, computed tomography and pathohistologic findings were tightly correlated, and characteristic of human disease. Immunologic monitoring demonstrated progressive evolution of high frequency M. tuberculosis-specific CD4(+) and CD8(+) T cell responses. Peripheral blood effector cell frequencies were similar to those observed in tissues. In summary, computed tomography scanning in conjunction with immunologic monitoring provides a non-invasive, accurate, and rapid assessment of tuberculosis in the non-human primate.

Abdominal cysticercosis in a rhesus macaque (Macaca mulatta).

A mid-abdominal mass was discovered during routine physical examination of a rhesus macaque (Macaca mulatta). Further diagnostics and exploratory laparotomy were performed, revealing a fluid-filled cyst attached to the caudal free margin of the greater omentum. Formation and pulsatile movement of white-colored circumferential bands within the wall of the cyst were observed during surgery. The cyst was removed and later was dissected. The discovery of a single invaginated scolex identified the cyst as a cysticercus. The location and characteristics of the cysticercus were consistent with the larval form of Taenia hydatigena.