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Expression of CTLA-4 in nonhuman primate lymphocytes and its use as a potential target for specific immunotoxin-mediated apoptosis: results of in vitro studies.

T-cell-mediated immunoregulation is one of the main mechanisms implicated in induction and maintenance of transplantation tolerance. In this regard, deletion or modulation of xeno/alloantigen-specific T cells, as well as blocking of their interactions with other cell populations, are currently being pursued for tolerance induction in humans as well as nonhuman primates. In order to investigate whether cytotoxic T-lymphocyte antigen-4 (CTLA-4) may represent a suitable target for a T cell depletion approach in nonhuman primate models, we analysed CTLA-4 expression in peripheral blood mononuclear cells (PBMCs) from nonhuman primates and the potential role of two anti-CTLA-4 saporin-conjugated immunotoxins. The analysis was performed in PBMCs from 8 cynomolgus monkeys from Philippines and from Mauritius both at protein level by flow cytometry and at transcriptional level by RT-PCR. In addition, the apoptotic role of the immunotoxins was investigated. The results showed that CTLA-4 was expressed at variable levels depending on the origin of the cynomolgus monkeys and the resting or activated cell condition. CTLA-4 was not expressed on resting Mauritius PBMCs and showed a lower up-regulation upon PMA/PHA activation compared to the Philippines PBMCs that expressed CTLA-4 also before activation. Two CTLA-4 RNA transcripts (672 and 550 bp) were detected with levels variations after cell stimulation. Two anti-CTLA-4 immunotoxins induced in vitro apoptosis of activated PBMCs from both sources of cynomolgus monkeys. This is the first report that documents CTLA-4 expression both at protein and transcriptional level by nonhuman primate PBMCs and provides novel perspectives of xeno/allograft rejection immunotherapy based on CTLA-4 targeting.

Animals↗

Comparative study of human monoclonal anti-D antibodies of IgG and IgM classes in tests with red cells of nonhuman primates.

Forty-nine human anti-D (Rho) monoclonal antibodies of the IgG and IgM classes were tested with red blood cells of various nonhuman primates, from anthropoid apes to Prosimians, and significant differences in reactivity were observed among antibodies of two classes depending on taxonomic position of primate animals. By and large, higher percentage of IgM mAbs gave positive reactions with nonhuman primate red cells and, particularly, with blood of lower monkeys: Old and New Worlds monkeys and Prosimians, than did those of IgG class. Allotypic reactions with red cells of African apes were produced by majority of IgG mAbs but by very few IgM reagents. Some of those reactions defined epitopes related to human D, such as chimpanzee Rc and gorilla Dgor. By contrast, individual differences among Old World monkey species were revealed almost exclusively in tests using anti-D mAbs of IgM class. Some of the epitopes detected by these antibodies on the red cells of macaques are related to human D alloantigen, as confirmed by absorption experiments. Differences among mAbs evidenced in tests with nonhuman primate red cells reflect the complexity of the immune reactions to the human D antigen.

Animals↗

Field methodology for lateral cranial radiography of nonhuman primates.

The historical lack of field-based radiographic studies of nonhuman primates within the field of anthropology is likely due to the perceived difficulty of transporting and operating X-ray equipment. Here we present a method for taking lateral cranial radiographs of nonhuman primates in the field that is simple to employ, and that produces exposed films suitable for collection of measurement data useful for growth and development studies, as well as for investigating bone and soft-tissue pathology. Several different X-ray units, film types, and portable power sources were used, all producing suitable images of similar quality, indicating that this methodology is likely not overly sensitive to these important parameters.

Animals↗

Urinary metabolites of 2, 5, 2', 5'-tetrachlorobiphenyl in the nonhuman primate.

The metabolism of 2, 5, 2', 5'-tetrachlorobiphenyl (TCB) in nonhuman primates was found to be different from that previously reported in lower species. Monohydroxy TCB (I), the only metabolite in the ether extracts of rat urine, is a minor metabolite in the urine of nonhuman primates. The two major metabolites identified in the urine were dihydroxy TCB (II) and trans-3,4-dihydro-3,4-dihydroxy TCB (III). A second minor metabolite was identified as hydroxy-3,4-dihydro-3,4-dihydroxy TCB (IV). None of the above mentioned metabolites have been reported in primates and only I and III have been identified in lower animals. It is concluded that a likely mechanism for metabolism of TCB in primates is through arene oxide intermediates. This observation is of particular importance in that these types of intermediates are known to alkylate cellular components causing carcinogenic, mutagenic, necrogenic and teratogenic effects.

Animals↗

Evaluation in nonhuman primates of vaccines against Ebola virus.

Ebola virus (EBOV) causes acute hemorrhagic fever that is fatal in up to 90% of cases in both humans and nonhuman primates. No vaccines or treatments are available for human use. We evaluated the effects in nonhuman primates of vaccine strategies that had protected mice or guinea pigs from lethal EBOV infection. The following immunogens were used: RNA replicon particles derived from an attenuated strain of Venezuelan equine encephalitis virus (VEEV) expressing EBOV glycoprotein and nucleoprotein; recombinant Vaccinia virus expressing EBOV glycoprotein; liposomes containing lipid A and inactivated EBOV; and a concentrated, inactivated whole-virion preparation. None of these strategies successfully protected nonhuman primates from robust challenge with EBOV. The disease observed in primates differed from that in rodents, suggesting that rodent models of EBOV may not predict the efficacy of candidate vaccines in primates and that protection of primates may require different mechanisms.

Animals↗

Transplantation of hepatocytes in nonhuman primates: a preclinical model for the treatment of hepatic metabolic diseases.

BACKGROUND: The transplantation of isolated hepatocytes in large animals, including nonhuman primates, must be evaluated before clinical trials are performed. However, in the absence of large transgenic animals and large-animal (as opposed to small-animal) models of genetic deficiencies, it is difficult to evaluate the fate of transplanted hepatocytes, their localization, survival, and function within the parenchyma of the host liver. In this work, we aimed to develop a technique for delivering hepatocytes to the liver of a nonhuman primate and to evaluate their localization and functionality in the short term. METHODS: A 20% hepatectomy was performed in 34 cynomolgus monkeys (Macaca fascicularis) and hepatocytes were isolated. Hepatocytes were labeled in vitro with a recombinant retrovirus expressing the beta-galactosidase gene and returned to the liver by infusion through a portal catheter left in place. Liver biopsies were performed 4 and 7 d after transplantation. RESULTS: Twenty-four monkeys underwent surgery to define the necessary technical adjustments and to optimize conditions. Six monkeys died. The whole protocol, including the transplantation of genetically marked hepatocytes and procurement of liver biopsies, was performed in the remaining 10 monkeys. In eight monkeys, transplanted hepatocytes expressing the beta-galactosidase gene were widely distributed in the portal tracts, sinusoids, and hepatocyte plates of the host liver 4 and 7 d after transplantation. CONCLUSIONS: We have developed an experimental nonhuman primate model for the evaluation of hepatocyte transplantation. We demonstrated the engraftment and functioning of transplanted hepatocytes in the host liver 4 and 7 d after transplantation.

Animals↗

Functional morphology of the first cervical vertebra in humans and nonhuman primates.

The cervical vertebral column bears or balances the weight of the head supported by the nuchal muscles that partly originate from the cervical vertebrae. The position of the head relative to the vertebral column, and consequently locomotion and posture behavior, could thus be associated with the form of the cervical vertebrae. In spite of this assumption and some empirical indications along these lines, primate vertebral morphologies have been reported to be very similar and not clearly related to locomotion. We therefore study the relationship between the morphology of the first cervical vertebra, the atlas, and the locomotion pattern within primates using a geometric morphometric approach. Our analysis is based on a total of 116 vertebrae of adult Homo sapiens, Gorilla gorilla, Pan troglodytes, Pongo pygmaeus, Hylobates lar, Macaca mulatta, Papio hamadryas, Ateles geoffroyi, and Alouatta palliata. On each atlas, 56 landmarks were digitized and superimposed by Procrustes registration. The resulting shape variables were analyzed by principal component analysis, multivariate regression, and partial least-squares analysis. We found that the nine primate species differ clearly in their atlas morphology and that allometric shape change is distinct between the nonhuman primates and Homo sapiens. We could further identify morphological features that relate to the species' locomotion pattern. Human atlas shape, however, cannot be predicted by an extrapolation of the nonhuman primate model. This implies that either the primate atlas is generalized enough to allow bipedal locomotion or else the human atlas morphology is a unique adaptation different from that in the more orthograde nonhuman primates.

Alouatta↗

Coagulation and thrombotic disorders associated with pig organ and hematopoietic cell transplantation in nonhuman primates.

BACKGROUND: Efforts to achieve tolerance to transplanted pig organs in nonhuman primates by the induction of a state of mixed hematopoietic chimerism have been associated with disorders of coagulation and thrombosis. Activation of recipient vascular endothelium and platelets by porcine hematopoietic cells and/or activation of donor organ vascular endothelium and/or molecular differences between the species may play roles. Irradiation or drug therapy could possibly potentiate endothelial cell activation and/or injury. METHODS: We have investigated parameters of coagulation and platelet activation in nonhuman primates after (1) a regimen aimed at inducing mixed hematopoietic chimerism and tolerance (TIR that included total body irradiation, T cell depletion, and splenectomy; (2) pig bone marrow or pig peripheral blood mobilized progenitor cell transplantation (PCTx); and/or (3) pig organ transplantation (POTx). Five experimental groups were studied. Baboons were the recipient subjects in all groups except Group 1. Gp 1 Cynomolgus monkeys (n=6) underwent TIR + allotransplantation of hematopoietic cells and a kidney or heart or TIR + concordant xenotransplantation (using baboons as donors) of cells and a kidney; Gp 2 Baboons (n=4) underwent TIR with or without (+/-) autologous hematopoietic cell infusion; Gp 3 (n=12) PCTx+/-TIR; Gp 4 (n=5) POTx+/-TIR; Gp 5 (n=4) TIR + PCTx + POTx. Platelet counts, with plasma prothrombin time, partial thromboplastin time, fibrinogen levels, fibrin split products and/or D-dimer were measured. RESULTS: In the absence of a discordant (porcine) cellular or organ transplant (Groups 1 and 2), TIR resulted in transient thrombocytopenia only, in keeping with bone marrow depression from irradiation. PCTx alone (Group 3) was associated with the rapid development of a thrombotic thrombocytopenic (TTP)-like microangiopathic state, that persisted longer when PCTx was combined with TIR. POTx (+/-TIR) (Group 4) was associated with a gradual fall (over several days) in platelet counts and fibrinogen with disseminated intravascular coagulation (DIC); after graft excision, the DIC generally resolved. When TIR, PCTx and POTx were combined (Group 5), an initial TTP-like state was superseded by a consumptive picture of DIC within the first week, necessitating graft removal. CONCLUSIONS: Both PCTx and POTx lead to profound alterations in hemostasis and coagulation parameters that must be overcome if discordant xenotransplantation of hematopoietic cells and organs is to be fully successful. Disordered thromboregulation could exacerbate vascular damage and potentiate activation of coagulation pathways after exposure to xenogeneic cells or a vascularized xenograft.

Animals↗

p53 gene mutation in hepatocellular carcinoma induced by 2-amino-3-methylimidazo[4,5-f]quinoline in nonhuman primates.

2-Amino-3-methylimidazo[4,5-f]quinoline (IQ) is one of several heterocyclic amines formed during the cooking of proteinaceous foods. IQ is a potent carcinogen in rodent bioassays and causes a high incidence of hepatocellular carcinomas in nonhuman primates. We examined 20 hepatocellular carcinomas (HCCs) from nonhuman primates for mutations of the p53 gene using polymerase chain reaction-single strand conformational polymorphism analysis. Mutations in the p53 gene were detected in 4 of 20 HCCs (20%) with 3 showing G-to-T transversions and one a G-to-A transition. Three of these mutations were observed in codons 175 and 248 that are known mutational hot spots in human cancers. These data indicate that part of the IQ-induced HCCs in nonhuman primates may involve inactivation of the p53 gene and suggest that IQ and possibly other heterocyclic amines may participate in human carcinogenesis by a similar mechanism.

Animals↗

Biosafety in acquired immunodeficiency syndrome (AIDS) studies using nonhuman primates.

The safety recommendations for studies on acquired immunodeficiency syndrome (AIDS) using nonhuman primates are based on knowledge about the epidemiology of the disease in humans, characteristics of the virus, and standard methods for handling nonhuman primates in the laboratory. Appropriate procedures avoid exposure to potentially infectious materials by skin puncture or to mucous membranes by using appropriate disinfecting agents, physical containment, protective clothing, and animal handling techniques.

Acquired Immunodeficiency Syndrome↗

Variations in adrenal androgen production among (nonhuman) primates.

The synthesis and secretion of the adrenal androgens dehydroepiandrosterone (DHEA) and its sulfate (DS) is a phenomenon apparently unique to humans and nonhuman primates. It occurs at three life stages: in utero from the fetal zone (FZ) cells of the developing adrenal cortex, during adolescence with the onset of adrenarche and the development of the zona reticularis (ZR), and in ever decreasing amounts from the ZR with aging (adrenal senescence). Insufficient data exist to know if any single nonhuman primate exactly mirrors human adrenal androgen secretion through all three life stages, and detailed morphological, biochemical, and endocrinologic studies are required to do so. Androgen synthesis requires that cells express three key enzymes, 17alpha-hydroxylase/17,20-lyase cytochrome P450 (P450c17), nicotinamide-adenine dinucleotide phosphate (NADPH)-cytochrome P450 oxidoreductase (CPR), and cytochrome b5, and that they do not express 3beta-hydroxysteroid dehydrogenase (3beta-HSD). Cytochrome b5 has emerged as a particularly useful marker of androgen synthetic potential. Although a reliable index of the rate of adrenal androgen secretion, DS concentrations may not accurately reflect total adrenal androgen output because rates and routes of androgen metabolism may vary greatly among species. Based on the very limited available data, the most promising nonhuman primate models are marmosets for the human FZ, chimpanzees for human adrenarche, and macaques and baboons for mature ZR function that declines with senescence.

Adrenal Glands↗

Varicella-like herpesvirus infections of nonhuman primates.

At least three distinct herpesviruses cause varicella like exanthematous diseases among nonhuman primates. Spontaneous epizootics have resulted in high morbidity and mortality rates among Cercopithecus aethiops, Erythrocebus patas and Macaca species in research colonies. Mild infections have been observed in infant chimpanzees and a gorilla. This group of diseases is of interest not only because they are a threat to primate colonies, but also because their pathologic similarity to progressive human varicella makes them a potentially valuable animal model of this disease. The nonhuman primate varicella-like exanthematous diseases are reviewed and compared to varicella in man.

Animals↗

Biological correlates of attachment bond disruption in humans and nonhuman primates.

Separations or disruptions in attachment bonds occur frequently in the social lives of humans and have been linked to the development of psychopathology. Separation of social nonhuman primates has been proposed as a model to study the psychological and biological effects of separation in humans. This paper reviews the biological alterations that occur in nonhuman primates undergoing separation and compares these with changes associated with separation in humans. The data reviewed demonstrate that separation in humans and nonhuman primates can be an event with profound behavioral and physiological sequelae.

Animals↗

A nonhuman primate version of the open field test for use in behavioral toxicology and teratology.

As reviewed here, little work has been done on testing nonhuman primates individually in open field paradigms. Hence, normative data from three studies of rhesus monkeys are presented. Important criteria for describing the pattern of activity exhibited by monkeys in the open field are introduced and the effects of gender and differences in rearing are assessed. Differences between this nonhuman primate version of the open field and that typically used with rodents are discussed, including reasons for differences in the variability of behavior between monkeys and rodents and a comparison of coefficients of detection (as an index of the power of the test to detect group differences). Overall, the use of the nonhuman primate version of the open field in behavioral toxicology and teratology is feasible and may fill a significant niche not presently well represented.

Animals↗

The effect of a menhaden oil-containing diet on hemostatic and lipid parameters of nonhuman primates with atherosclerosis.

Three species of nonhuman primates were fed an atherogenic diet for 6 months (baseline period) and a menhaden oil (EPA)-containing diet for 8 weeks (test period) during which various hemostatic and lipid parameters were compared. The EPA-rich diet prolonged bleeding times, inhibited platelet aggregation response to ADP and collagen, and increased mean platelet lifespan. This diet elicited an increase in the polyunsaturated fatty acids C20:5 (EPA) and C22:6 (docosahexaenoic acid) at the expense of C18:2 (linoleic acid) and C20:4 (arachidonic acid) in pooled samples of platelet membranes, creating an increase in the ratio of n-3/n-6 polyunsaturated fatty acids. The serum lipid response to a menhaden oil diet comprised a nonsignificant decrease in total serum cholesterol and a significant decrease in HDL cholesterol.

Animals↗

Biomechanical and histologic evaluations of pulley reconstructions in nonhuman primates.

A2 pulleys were reconstructed in nonhuman primates using expanded polytetrafluoroethylene, woven nylon, and fascia. Biomechanical and histologic evaluations were done after death at 18 weeks. Tendons were normal after all pulley reconstructions. Polytetrafluorethylene had a greater breaking strength than woven nylon or fascia, or control pulleys, both at 18 weeks and before implantation. Histologic analyses revealed fibrous ingrowth of host tissues, no adhesions, no trauma to underlying flexor tendons, and the absence of an inflammatory response, for all pulley types.

Animals↗

Factors affecting the interpretation of canine and nonhuman primate clinical pathology.

Interpreting canine and nonhuman primate clinical pathology data from preclinical studies can be challenging. Relatively few animals are tested (typically beagles and macaques), and they often undergo study-related procedures (eg, sample collection for pharmacokinetic analysis) that can affect clinical pathology test results. Data interpretation requires an understanding of the significance of each test, species differences for each test, normal interanimal and intraanimal variability, the effects of study design variables, and supporting data from other disciplines. Interpretation of hematology, coagulation, clinical chemistry, and urinalysis parameters are discussed, with emphasis on species peculiarities and study design variables that may affect clinical pathology test results.

Animals↗

Functional properties of nonhuman primate antibody to Porphyromonas gingivalis.

The nonhuman primate (NHP) serves as a useful model for examining the host-parasite interactions in Porphyromonas gingivalis-associated periodontal disease. This study determined the influence of NHP sera on (i) the direct killing of P. gingivalis, (ii) P. gingivalis-induced superoxide anion (O2-) release from human polymorphonuclear leukocytes (PMNs), and (iii) the ability of PMNs to bind and phagocytize P. gingivalis. Three types of NHP sera were utilized: (i) normal or baseline sera; (ii) sera obtained after ligature-induced periodontitis; and (iii) sera obtained following active immunization with formalinized P. gingivalis. All assays were performed with or without the addition of human complement. Significantly more (P < 0.01) direct killing of P. gingivalis occurred with immunized sera and complement than with any of the other treatments. The sera from ligature-induced periodontitis NHPs had significantly less (P < 0.03) killing capacity than the baseline sera, which contained natural antibody produced to P. gingivalis colonization. Sera from immunized NHPs were used to opsonize P. gingivalis and caused significantly greater (P < 0.01) levels of O2- release from PMNs. Finally, the sera from immunized NHPs significantly enhanced (P < 0.009) the uptake of P. gingivalis by PMNs, although binding of the bacteria to PMNs was similar among all three serum types. Active immunization of NHPs with P. gingivalis elicited a functional antibody that enhanced direct killing, positively influenced the activation of PMNs, and enhanced the ability of PMNs to phagocytize P. gingivalis. Moreover, antibody produced as a sequela of progressing periodontitis appeared to lack these functions. A wide variability in functional capacity of the sera from individual NHPs, which may contribute to an individual's susceptibility to P. gingivalis-induced disease, was noted. This variability suggested that results from functional tests of serum antibody may aid in predicting host susceptibility to disease and response to therapy.

Adult↗