Use of convalescent serum reduces severity of COVID-19 in nonhuman primates.

Passive transfer of convalescent plasma or serum is a time-honored strategy for treating infectious diseases. Human convalescent plasma containing antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently being used to treat patients with coronavirus disease 2019 where clinical efficacy trials are ongoing. Here, we assess therapeutic passive transfer in groups of SARS-CoV-2-infected African green monkeys with convalescent sera containing either high or low anti-SARS-CoV-2 neutralizing antibody titers. Differences in viral load and pathology are minimal between monkeys that receive the lower titer convalescent sera and untreated controls. However, lower levels of SARS-CoV-2 in respiratory compartments, reduced severity of virus-associated lung pathology, and reductions in coagulopathy and inflammatory processes are observed in monkeys that receive high titer sera versus untreated controls. Our data indicate that convalescent plasma therapy in humans may be an effective strategy provided that donor sera contain high anti-SARS-CoV-2 neutralizing titers given in early stages of the disease.

Epilepsy in nonhuman primates.

OBJECTIVES: Nonhuman primates (NHPs) are model organisms for understanding the pathophysiology and treatment of epilepsy in humans, while data from human patients informs the diagnosis and treatment of NHP with seizures and epilepsy. We reviewed the literature and surveyed veterinarians at zoos and NHP research centers to (a) better define the range of seizures and epilepsy in NHP, (b) understand how NHPs can inform our knowledge of the pathophysiology and treatment of epilepsy in humans, and (c) identify gaps of knowledge and develop more effective guidelines to treat seizures and epilepsy in NHP. METHODS: We searched PrimateLit, PubMed, and Google Scholar for studies on experimental models of epilepsy in NHPs and on naturally occurring seizures and epilepsy in NHPs in captivity. In addition, we created a survey to assess methods to diagnose and treat epilepsy in NHPs. This survey was sent to 41 veterinarians at major international zoos and research facilities with NHP populations to study seizure phenomenology, diagnostic criteria for seizures and epilepsy, etiology, and antiseizure therapies in NHPs. RESULTS: We summarize the data from experimental and natural models of epilepsy in NHPs and case reports of epilepsy of unknown origin in captive primates. In addition, we present survey data collected from veterinarians at eight zoos and one research facility. Experimental data from NHP epilepsy models is abundant, whereas data from primates who develop epilepsy in the wild or in zoos is very limited, constraining our ability to advance evidence-based medicine. SIGNIFICANCE: Characterization of seizure or epilepsy models in NHPs will provide insights into mechanisms and new therapies that cannot be addressed by other animal models. NHP research will better inform species-specific diagnoses and outcomes.

Post-exposure immunotherapy for two ebolaviruses and Marburg virus in nonhuman primates.

The 2013-2016 Ebola virus (EBOV) disease epidemic demonstrated the grave consequences of filovirus epidemics in the absence of effective therapeutics. Besides EBOV, two additional ebolaviruses, Sudan (SUDV) and Bundibugyo (BDBV) viruses, as well as multiple variants of Marburg virus (MARV), have also caused high fatality epidemics. Current experimental EBOV monoclonal antibodies (mAbs) are ineffective against SUDV, BDBV, or MARV. Here, we report that a cocktail of two broadly neutralizing ebolavirus mAbs, FVM04 and CA45, protects nonhuman primates (NHPs) against EBOV and SUDV infection when delivered four days post infection. This cocktail when supplemented by the anti-MARV mAb MR191 exhibited 100% efficacy in MARV-infected NHPs. These findings provide a solid foundation for clinical development of broadly protective immunotherapeutics for use in future filovirus epidemics.

Evidence for the possible occurrence of Grave's disease in a blue-eyed black lemur (Eulemur flavifrons).

The blue-eyed black lemur (Eulemur flavifrons) is classified by the International Union for Conservation of Nature (IUCN) as critically endangered. A 23-year-old male housed at Mulhouse Zoo presented with lethargy, polyphagia, alopecia, and chronic weight loss. Clinical examination suggested an endocrine pathology such as hyperthyroidism. Secondary examinations included cervical ultrasound, thyroid biopsy, and scintigraphy. The latter revealed elevated thyroid activity. Blood analysis was performed to measure the level of anti-receptor thyroid-stimulating hormone antibodies, which allowed us to test the autoimmune hypothesis. The high level of antibodies together with levels of thyroid-stimulating hormone and the scintigraphy images led to the diagnosis of Grave's disease. Carbimazole treatment followed by thyroidectomy resulted in a quick weight gain and general improvement in health status. The following breeding season, the treated individual sired an offspring. To the authors' knowledge, this is the first report of likely Grave's disease in a non-human primate.

Euthanasia assessment in ebola virus infected nonhuman primates.

Multiple products are being developed for use against filoviral infections. Efficacy for these products will likely be demonstrated in nonhuman primate models of filoviral disease to satisfy licensure requirements under the Animal Rule, or to supplement human data. Typically, the endpoint for efficacy assessment will be survival following challenge; however, there exists no standardized approach for assessing the health or euthanasia criteria for filovirus-exposed nonhuman primates. Consideration of objective criteria is important to (a) ensure test subjects are euthanized without unnecessary distress; (b) enhance the likelihood that animals exhibiting mild or moderate signs of disease are not prematurely euthanized; (c) minimize the occurrence of spontaneous deaths and loss of end-stage samples; (d) enhance the reproducibility of experiments between different researchers; and (e) provide a defensible rationale for euthanasia decisions that withstands regulatory scrutiny. Historic records were compiled for 58 surviving and non-surviving monkeys exposed to Ebola virus at the US Army Medical Research Institute of Infectious Diseases. Clinical pathology parameters were statistically analyzed and those exhibiting predicative value for survival are reported. These findings may be useful for standardization of objective euthanasia assessments in rhesus monkeys exposed to Ebola virus and may serve as a useful approach for other standardization efforts.

Development of an inhalational Bacillus anthracis exposure therapeutic model in cynomolgus macaques.

Appropriate animal models are required to test medical countermeasures to bioterrorist threats. To that end, we characterized a nonhuman primate (NHP) inhalational anthrax therapeutic model for use in testing anthrax therapeutic medical countermeasures according to the U.S. Food and Drug Administration Animal Rule. A clinical profile was recorded for each NHP exposed to a lethal dose of Bacillus anthracis Ames spores. Specific diagnostic parameters were detected relatively early in disease progression, i.e., by blood culture (∼37 h postchallenge) and the presence of circulating protective antigen (PA) detected by electrochemiluminescence (ECL) ∼38 h postchallenge, whereas nonspecific clinical signs of disease, i.e., changes in body temperature, hematologic parameters (ca. 52 to 66 h), and clinical observations, were delayed. To determine whether the presentation of antigenemia (PA in the blood) was an appropriate trigger for therapeutic intervention, a monoclonal antibody specific for PA was administered to 12 additional animals after the circulating levels of PA were detected by ECL. Seventy-five percent of the monoclonal antibody-treated animals survived compared to 17% of the untreated controls, suggesting that intervention at the onset of antigenemia is an appropriate treatment trigger for this model. Moreover, the onset of antigenemia correlated with bacteremia, and NHPs were treated in a therapeutic manner. Interestingly, brain lesions were observed by histopathology in the treated nonsurviving animals, whereas this observation was absent from 90% of the nonsurviving untreated animals. Our results support the use of the cynomolgus macaque as an appropriate therapeutic animal model for assessing the efficacy of medical countermeasures developed against anthrax when administered after a confirmation of infection.

Novel therapeutic vaccine: granulysin and new DNA vaccine against Tuberculosis.

PURPOSE: Multi-drug resistant (MDR) Mycobacterium Tuberculosis (M.TB) is a big problem in the world. We have developed novel TB therapeutic vaccines. METHODS AND RESULTS: DNA vaccine expressing mycobacterial heat shock protein 65 and IL-12 was delivered by the hemagglutinating virus of Japan (HVJ)-envelope. M. TB, MDR-TB or extremenly drug resistant (XDR-TB) was injected i.v. into DBA/1 mice, and treated with the vaccine three times. This HVJ-E/Hsp65DNA+IL-12DNA vaccine provided strong therapeutic efficacy against MDR-TB and XDR-TB (prolongation of survival time and the decrease in the number of TB) in mice. Therapeutic effect of this vaccine on TB infection was also demonstrated in chronic TB infection murine model using aerosol infection intratracheally. On the other hand, granulysin protein produced from CTL has lethal activity against TB. Granulysin protein vaccine also exerted strong therapeutic effect. Furthermore, we extended our studies to monkey model, which is currently the best animal model of human TB. Hsp65DNA+IL-12 DNA vaccine exerted strong therapeutic efficacy (100% survival and augmentation of immune responses) in the TB-infected monkeys. In contrast, the survival of the saline control group was 60% at 16 week post-challenge. HVJ-Envelope/HSP65 DNA+IL-12 DNA vaccine increased the body weight of TB-infected monkeys, improved the erythrocyte sedimentation rate, and augmentated the immune responses (proliferation of PBL and IL-2 production). The enhancement of IL-2 production from monkeys treated with this vaccine was correlated with the therapeutic efficacy of the vaccine. CONCLUSION: These data indicate that novel vaccines might be useful against TB including XDR-TB and MDR-TB for human therapeutic clinical trials.

Diagnosis and prevalence of uterine leiomyomata in female chimpanzees (Pan troglodytes).

Uterine leiomyomata are common, affecting 70-80% of women between 30 and 50 years of age. Leiomyomata have been reported for a variety of primate species, although prevalence rates and treatments have not been widely reported. The prevalence, diagnosis, and treatment of uterine leiomyomata in the Alamogordo Primate Facility and the Keeling Center for Comparative Medicine and Research were examined. Uterine leiomyomata were diagnosed in 28.4% of chimpanzees with an average age at diagnosis of 30.4 ± 8.0 years. Advanced age (>30 years) was related to an increase in leiomyomata and use of hormonal contraception was related to a decrease in leiomyomata. As the captive chimpanzee population ages, the incidence of leiomyomata among female chimpanzees will likely increase. The introduction of progesterone-based contraception for nonbreeding research and zoological chimpanzees may reduce the development of leiomyomata. Finally, all chimpanzee facilities should institute aggressive screening programs and carefully consider treatment plans.

A non-glycosylated, plant-produced human monoclonal antibody against anthrax protective antigen protects mice and non-human primates from B. anthracis spore challenge.

The health and economic burden of infectious diseases in general and bioterrorism in particular necessitate the development of medical countermeasures. One proven approach to reduce the disease burden and spread of pathogen is treatment with monoclonal antibodies (mAb). mAbs can prevent or reduce severity of the disease by variety of mechanisms, including neutralizing pathogen growth, limiting its spread from infected to adjacent cells, or by inhibiting biological activity of toxins, such as anthrax lethal toxin. Here, we report the production of glycosylated (pp-mAb (PA) ) and non-glycosylated (pp-mAb (PANG) ) versions of a plant-derived mAb directed against protective antigen (PA) of Bacillus anthracis in Nicotiana benthamiana plants using agroinfiltration. Both forms of the antibody were able to neutralize anthrax lethal toxin activity in vitro and protect mice against an intraperitoneal challenge with spores of B. anthracis Sterne strain. A single 180 µg intraperitoneal dose of pp-mAb (PA) or pp-mAb (PANG) provided 90% and 100% survival, respectively. When tested in non-human primates, pp-mAb (PANG) was demonstrated to be superior to pp-mAb (PA) in that it had a significantly longer terminal half-life and conferred 100% protection against a lethal dose of aerosolized anthrax spore challenge after a single 5 mg/kg intravenous dose compared to a 40% survival rate conferred by pp-mAb (PA) . This study demonstrates the potential of a plant-produced non-glycosylated antibody as a useful tool for the treatment of inhalation anthrax.

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.

Use of desferoxamine and S-adenosylmethionine to treat hemochromatosis in a red ruffed lemur (Varecia variegata ruber).

Hemochromatosis was diagnosed in a 14-year-old, male, red ruffed lemur (Varecia variegata ruber) on the basis of abnormal results of serum biochemical analysis, including high serum ferritin and transferrin saturation values, and of liver biopsy. Therapy included chelation, using desferoxamine to remove excess iron and S-adenosylmethionine to improve liver function, and monthly peripheral blood removal by phlebotomy to reduce total body iron content. Response to treatment was assessed by changes in the lemur's attitude and appetite, as well as variations in serum biochemical and iron panel values. Initial improvement was associated with the onset of therapy. After 56 days of treatment, results of serum biochemical analysis indicated a decrease in iron panel values. Treatment was temporarily discontinued from days 56 to 65, and the lemur's condition worsened, so therapy was re-instituted. However, the lemur died of hepatocellular carcinoma on day 110 of treatment.

Nonhuman primate dentistry.

Dental procedures in nonhuman exotic primates present many out of the ordinary problems that are related to variations of the teeth and oral cavity and serious zoonotic considerations and procedural time limitations. Most of these challenges can be met with appropriate knowledge, training, equipment, and rapidity and precision in performance. Unfortunately, alacrity generally comes from repetitive performance of procedures and entails a learning curve.

Marburg and Ebola virus infections in laboratory non-human primates: a literature review.

BACKGROUND AND PURPOSE: Several non-human primate species are used as laboratory animals for various types of studies. Although importation of monkeys may introduce different diseases, special attention has recently been drawn to Marburg and Ebola viruses. This review presented here discusses the potential risk of these viruses for persons working with non-human primates as laboratory animals by focusing on epidemiology, virology, symptoms, pathogenesis, natural reservoir, transmission, quarantine of non-human primates, therapy, and prevention. CONCLUSION: A total of 23 Marburg and Ebola virus outbreaks causing viral hemorrhagic fever has been reported among humans and monkeys since the first outbreak in Marburg, Germany in 1967. Most of the 1,100 human cases, with nearly 800 deaths, developed in Africa due mainly to direct and intimate contact with infected patients. Few human cases have developed after contact with non-human primates used for various scientific purposes. However, adequate quarantine should be applied to prevent human infections not only due to Marburg and Ebola viruses, but also to other infective agents. By following proper guidelines, the filovirus infection risk for people working with non-human primates during quarantine exists, but is minimal. There seems to be little risk for filovirus infections after an adequate quarantine period. Therefore, non-human primates can be used as laboratory animals, with little risk of filovirus infections, provided adequate precautions are taken.