Homologous and heterologous protection of nonhuman primates by Ebola and Sudan virus-like particles

Filoviruses cause hemorrhagic fever resulting in significant morbidity and mortality in humans. Several vaccine platforms that include multiple virus-vectored approaches and virus-like particles (VLPs) have shown efficacy in nonhuman primates. Previous studies have shown protection of cynomolgus macaques against homologous infection for Ebola virus (EBOV) and Marburg virus (MARV) following a three-dose vaccine regimen of EBOV or MARV VLPs, as well as heterologous protection against Ravn Virus (RAVV) following vaccination with MARV VLPs. The objectives of the current studies were to determine the minimum number of vaccine doses required for protection (using EBOV as the test system) and then demonstrate protection against Sudan virus (SUDV) and Taï Forest virus (TAFV). Using the EBOV nonhuman primate model, we show that one or two doses of VLP vaccine can confer protection from lethal infection. VLPs containing the SUDV glycoprotein, nucleoprotein and VP40 matrix protein provide complete protection against lethal SUDV infection in macaques. Finally, we demonstrate protective efficacy mediated by EBOV, but not SUDV, VLPs against TAFV; this is the first demonstration of complete cross-filovirus protection using a single component heterologous vaccine within the Ebolavirus genus. Along with our previous results, this observation provides strong evidence that it will be possible to develop and administer a broad-spectrum VLP-based vaccine that will protect against multiple filoviruses by combining only three EBOV, SUDV and MARV components.

Effects of age and sex on the hematology and blood chemistry of Tibetan macaques (Macaca thibetana)

Tibetan macaques (Macaca thibetana), also known as Chinese stump-tailed macaques, are a threatened primate species. Although Tibetan macaques are Old World monkeys in the genus of Macaca, limited age- and sex-related physiologic data are available for this particular species. We used 69 apparently healthy Tibetan male and female macaques to explore the effect of age and sex on physiologic parameters. Somatometric measurements, biochemistry, and hematologic parameters were analyzed. Significant age-related differences were found for weight, BMI, RBC count, Hgb, Hct, neutrophils, eosinophil count, ALT, AST, ALP, GGT, creatine kinase (muscle and brain subtypes), LDH, α-amylase, creatinine, apolipoprotein A1, total protein, albumin, cholesterol, HDL, and potassium. Significant differences by sex were noted for weight, BMI, ALT, total bilirubin, and indirect bilirubin. An interaction between age and sex accounted for statistically significant differences in the values for weight, BMI, and lymphocyte and eosinophil counts. These physiologic data will provide veterinarians and researchers with important age- and sex-specific reference ranges for evaluating experimental results from Tibetan macaques.

Further characterization of the G blood group system of rhesus monkeys

We describe a new antiserum that has the unique ability to distinguish homozygous from heterozygous genotypes in the G blood group system of rhesus monkeys. With this new typing serum (reagent), all 10 possible genotypes in this system can be distinguished and the utility of blood typing for genetic studies has been greatly increased.

The human Duffy blood group in rhesus monkeys

There is good evidence that susceptibility to Plasmodium vivax infection and to P. knowlesi erythrocyte invasion is influenced by certain human Duffy (Fy) blood group antigens. Since P. knowlesi readily infects rhesus monkeys (Macaca mulatta), it was not surprising to find an Fy-like antigen on rhesus erythrocytes. Using human Fy antisera in elution and absorption experiments, we found that all 40 rhesus monkeys tested displayed the Fy(a-b+) phenotype. Furthermore, the rhesus Fyb antigen was inactivated by chymotrypsin but not by trypsin, suggesting that it is homologous to the human Fyb antigen. Preliminary serological analyses and enzyme hydrolysis experiments suggest that none of the 13 blood group systems that we have described in rhesus are analogous to the human Fy system. Thus, it appears that there is no Duffy-like polymorphism in rhesus monkeys.

Immunogenetic studies of rhesus monkeys. 6. Absence of the human Xga blood group on rhesus erythrocytes

It was not possible to demonstrate Xga on the erythrocytes of any of 140 rhesus monkeys of both sexes tested with human antiserum rendered specific for Xga by absorption.

A microagglutination test for blood typing rhesus monkeys, Macaca mulatta

We have developed a microagglutination test for typing rhesus monkey erythrocytes that is sensitive, accurate and easy to perform. The technique requires only microliter quantities of antiserum and cells, and agglutination is easily detected using an inverted microscope. An advantage of this technique is that the typing plates can be stored at -70 degrees C without loss of activity. The results of typing over 400 rhesus blood samples with this technique were 95% concordant with results using the standard microtitre agglutination technique. Preliminary results indicate that this test is also adaptable to typing human blood.

Passive immunization with human neutralizing monoclonal antibodies against HIV-1 in macaque models: experimental approaches

After more than 20 years of intense research, a safe and effective vaccine against HIV-1/AIDS has not been developed. Passive immunization has been used as a tool to demonstrate the role of neutralizing antibodies in conferring protection against HIV-1 challenge in chimpanzees. Because these animals are endangered and studies are difficult to conduct with this species, chimeric viruses, termed simian-human immunodeficiency viruses (SHIVs), have been generated that encode the HIV-1 envelope gene in the backbone of the simian immunodeficiency virus (SIV). SHIVs replicate in several macaque species and can induce AIDS in these animals. Passive immunization with human neutralizing monoclonal antibodies (nmAbs) against HIV-1 has protected rhesus macaques from SHIV infection and provided proof-of-concept of the protective effects of neutralizing antibodies. At the same time, human nmAbs can be evaluated for safety and efficacy in the SHIV/macaque model as therapeutic modalities in their own right for prevention, post-exposure prophylaxis, or possibly therapeutic use. Experimental details are provided for testing human nmAbs in infant rhesus monkeys, which allows testing without the need to generate large amounts of nmAbs.

Divergent expression of cellular prion protein on blood cells of human and nonhuman primates

BACKGROUND

Four recent transmissions of variant Creutzfeldt-Jakob disease infection by transfusion highlight the need for detailed understanding of blood-related prion pathogenesis. Nonhuman primates are the most relevant models of human prion diseases.

STUDY DESIGN AND METHODS

Quantitative flow cytometry with monoclonal antibodies FH11, 3F4, and 6H4 against different parts of the normal cellular form of the prion protein (PrP(C)) was used to evaluate its expression on blood cells of humans, chimpanzees, cynomolgus macaques, rhesus macaques, squirrel monkeys, and microcebe lemurs.

RESULTS

Chimpanzees, rhesus macaques, and squirrel monkeys displayed a much higher quantity of total blood cell membrane PrP(C) than humans, due to a markedly higher expression of PrP(C) on their red blood cells (RBCs). In contrast, cynomolgus macaques and lemurs demonstrated substantially lower levels of membrane PrP(C) due to the lack of significant PrP(C) expression on RBCs and platelets (PLTs). All species displayed PrP(C) on white blood cells (WBCs), with the highest levels found on human cells. Only humans, chimpanzees, and to a lesser degree rhesus macaques expressed PrP(C) on PLTs.

CONCLUSION

If PrP(C) contributes to the propagation or transport of prion infectivity in blood, the differences reported here need to be considered when extrapolating results of transmission studies in primate models to blood and blood components in humans.

Changes in the titer of anti-B virus antibody in captive macaques (Macaca fuscata, M. mulatta, M. fascicularis)

Changes in levels of antibody to B virus (Cercopithecine herpesvirus 1; BV) were examined in BV-positive macaques by ELISA. We observed increases in anti-BV IgG titers in a BV-infected cynomolgus monkey after overseas transportation by air and in a rhesus monkey after transfer from an outdoor group cage to an indoor individual cage. Although shedding of infectious virus was not examined, the increase in antibody titer suggested reactivation of BV. Interestingly, we also found an increase in anti-BV IgG levels during the breeding season in male but not female Japanese macaques kept in an enclosed outdoor colony. Further studies should be performed to investigate whether reactivation of BV led to the observed increase in the anti-BV antibody titer.

Characterization of obesity in Japanese monkeys (Macaca fuscata) in a pedigreed colony

BACKGROUND

Japanese monkey, Macaca fuscata, is recognized as the monkey species inhabiting the northernmost area in the world, and thus likely to possess unique fat-depositing mechanisms to resist cold weather in winter. We report that obese females are present in the Wakasa group of Japanese monkey reared in an open enclosure of the Primate Research Institute, Kyoto University.

METHODS AND RESULTS

Eight of 12 females were categorized as obese, showing percentage body fat of over 22%. The levels of serum leptin (mean +/- SD, 4.9 +/- 2.3 ng/ml) measured in these obese monkeys were significantly higher than those of non-obese peers of the same group (n = 4; 1.2 +/- 0.5 ng/ml) and another Japanese monkey group (Takahama, n = 14; 0.8 +/- 0.25 ng/ml); however, serum levels of adiponectin, insulin, glucose, hemoglobin A1c, and fructosamine did not differ between obese and non-obese monkeys. Few serum lipid parameters such as triglyceride and cholesterol showed lower levels in obese monkeys than their non-obese peers.

CONCLUSIONS

These results show that these obese monkeys in the Wakasa group have not developed obesity-related diseases/disorders such as diabetes. In the Wakasa group, the frequency of obese individuals was high in some maternal lineages, suggesting that genetic factors responsible for obesity may have been inherited in these lineages.

Changes in testicular and nipple volume related to age and seasonality in Japanese macaques (Macaca fuscata), especially in the pre- and post-pubertal periods

We investigated, longitudinally and cross-sectionally, age and seasonal change in both the testis and nipple volume of Japanese macaques (Macaca fuscata) in relation to concentration profiles of gonadal steroids: testosterone (T) in males and progesterone (P) in females. Testicular volume (TV) and nipple volume (NV) showed rapid growth at puberty, 4.5 and 3.5 years of age in males and females, respectively, but in both sexes there were precocious individuals. The testis as a whole matures at about 10 years of age. TV change is closely related to T concentration profile. The pattern of TV change is composed of maturation and seasonal effects, with individual variation evident mainly in the latter. Some individuals show a simple pattern consisting of one peak in the breeding season (from summer to winter) and one trough in the non-breeding season. Other individuals exhibit a more complicated pattern composed of two or more peaks and troughs before and during the breeding season. The nipple matures at about 7 years but it is difficult to determine the exact maturational age as there are many confounding factors relating to NV. NV shows seasonal fluctuations similar to that of TV. Many animals have periods of substantial growth whereas others do not. The NV in adults from 10 to 25 years does not appear to change much with age, but animals older than 25 years of age have significantly smaller nipples. Seasonal fluctuation in NV mirrors that of the P level. Considered to be controlled by estrogen and P, the NV is a good indicator of the physiological status of reproduction, with its peak about 2 weeks earlier than that of P, that is, at the mid-follicular phase. NV and P level show a similar pattern in pregnancy; from conception, indicated by a P peak, NV and P concentration first decrease, then they increase until peri-parturition and slowly decrease again until the next breeding season.

Hematology of a natural population of toque macaques (Macaca sinica) at polonnaruwa, Sri Lanka

Hematological studies were conducted in three wild groups of toque macaques (Macaca sinica) inhabiting the Polonnaruwa Sanctuary in northeastern Sri Lanka. The macaques were temporarily trapped and anesthetized, and femoral blood was drawn from 35 males and 37 females (age range: 0.33-24.5 yr). Statistically significant (P<0.05) differences were observed by sex for total plasma proteins (PP), and by age for red blood cell (RBC) counts, hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular Hb (MCH), mean corpuscular Hb concentration (MCHC), PP, erythrocyte sedimentation rate (ESR), differential and absolute neutrophil counts, differential lymphocyte counts, and absolute eosinophil counts. In general, the results were similar to those reported for other species of colony-bred and free-ranging macaques. However, there also were differences. First, in contrast to earlier studies of nonhuman primates, we examined the hematology of infants. Compared to other age classes, infants (<1 yr old) had lower RBC, Hb, MCHC, and ESR values, and a higher MCV. These findings were similar to those obtained in human infants. Second, we observed variations in hematology among social groups in relation to their ecology. Two groups (IH3 and M3) had ready access to water throughout the dry season (the period of sampling), whereas the third group (J) did not. The Hb, RBC, and PP values obtained in groups IH3 and M3 were similar to those reported in other macaque species. However, these parameters in group J were significantly (P<0.01) higher, which suggests that this group (representing about 26% of the sample) had been dehydrated during the dry season. Finally, two indices indicative of injury and infection--the ESR and leukocyte counts--were higher in the wild toque macaques than has been reported for other species of macaques held in captivity, and about 15% of the toque macaques sampled had extreme outlier values for these parameters; however, none were visibly ill or died. These results suggest that wild toque macaques are subject to a wide array of physical and biological insults that are unique to natural populations.

Increased plasma levels of soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell molecule-1 (sVCAM-1) associated with disease severity in a primate model for severe human malaria: Plasmodium coatneyi-Infected Japanese macaques (Macaca fuscata)

In the present study, we investigated plasma levels of soluble intercellular adhesion molecule-1 (sICAM-1) and vascular cell adhesion molecule-1 (sVCAM-1) in seven Japanese macaques (Macaca fuscata) infected with Plasmodium coatneyi. Concentrations of sICAM-1 and sVCAM-1 were significantly elevated in the severe phase; the levels were maximally increased up to six times and three times those before infection, respectively. We subsequently examined kinetic profiles of sICAM-1 and sVCAM-1 concentration in plasma obtained from two infected monkeys. Both infected monkeys had markedly increased levels of these adhesion molecules when they exhibited severe clinical signs correlated with rapid increase in parasitemia. These results suggest that the elevation of levels of sICAM-1 and sVCAM-1 is a critical step in the pathogenesis of severe malaria in vivo.

Mother-infant relationships and maternal estrogen metabolites changes in macaques (Macaca fuscata, M. mulatta)

This research assessed mother-infant relationships in rhesus and Japanese macaques living in analogous captive social groups, and monitored changes in the levels of excreted estrogen metabolites during the peripartum period. Each mother-infant pair was focally observed 3 h per week during the first 12 weeks of life of newborns. Fecal samples were collected twice a week from each mother, starting 4 weeks before delivery and ending 4 weeks after delivery. Infant-directed behaviors appeared to be consistently less protective/controlling and more rejecting in rhesus macaques than in Japanese macaques. Estrogen metabolite levels during the perinatal period were, on average, 3-fold higher in Japanese macaques and showed a sharp increase during the last weeks of pregnancy only in the Japanese macaque group. Considering the ecological and behavioral similarities between Japanese and rhesus macaques, the divergence between the two species in the onset and maintenance of maternal behavior was unexpected. This was possibly linked to the difference in the overall body size and life history, and to the striking divergence in estrogen metabolite variation during the peripartum period. Group size, social relationships, and average age of individuals in the two captive groups were not clearly involved in the recorded differences in maternal behavior.

Plasmodium coatneyi-infected erythrocytes bind to C32 amelanotic melanoma cells under static and flow conditions

The ability of Plasmodium coatneyi-infected red blood cells (IRBCs) to bind to C32 amelanotic melanoma cells was examined under static and physiologic flow conditions in vitro. Six blood samples obtained from P. coatneyi-infected Japanese macaques (Macaca fuscata) with severe manifestations of disease were used in the static adhesion assay. All blood samples constantly exhibited binding of IRBCs to C32 cells under static conditions. Immunofluorescence staining with anti-CD36 mAb revealed a positive reaction at the surface of C32 cells with the infected erythrocytes, while the reaction with C32 cells without IRBCs was negative. To further examine the specificity of the interaction between P. coatneyi-infected erythrocytes and C32 cells, we carried out the binding assay under physiological flow conditions. In flow adhesion assay, three blood samples were used. Adhesion and rolling of IRBCs on C32 cells were detected at several rates of shear stress under flow conditions. At a shear stress of 1.0 dyne/cm(2), the number of IRBCs adherent to C32 cell averaged 5 to 6, and the number of IRBCs rolling on C32 cells averaged 6 to 11. The anti-CD36 mAb OKM5 inhibited 75-100% of IRBC adhesion and rolling, while the inhibitory effect of anti-ICAM-1 mAb 84H10 varied between 20-40%. The combination of anti-CD36 and anti-ICAM-1 mAb resulted in 83-100% inhibition of rolling and 100% inhibition of adhesion. These findings suggest that CD36 is one of the principal adhesion receptors of P. coatneyi-infected erythrocytes.

Baseline and stress levels of cortisol in conscious and unrestrained Japanese macaques (Macaca fuscata)

A vest and tethering system was applied to Japanese macaques (Macaca fuscata) to collect blood samples under less stressful conditions. The level of plasma cortisol was assayed to assess the amount of stress. The pattern of plasma cortisol fluctuation during 24 hours was consistent under non-stress conditions. The plasma cortisol level was increased significantly by encounter and venipuncture. The increase was especially noteworthy when the experimental macaques encountered a large adult male, reflecting the strong stress on macaques. As venipuncture is a common medical procedure, and the encounter between macaques who have never met before occurs frequently, this vest and tethering system is useful for the assessment of the amount of stress in the daily care of macaques in a laboratory.

Isolation of peripheral blood mononuclear cells from macaques on a density barrier

The standard techniques for the isolation of human peripheral blood mononuclear cells (PBMCs) using commercial "lymphocyte isolation media" cannot be satisfactorily extended to experimental animals without manipulating either the density or the osmolality of the medium. PBMCs from Macaques can also be isolated from whole blood by sedimentation on to a density barrier containing approx. 10% iodixanol, polysucrose (Ficoll) with a density of approx 1.074 g/ml.

Primary replication of a recombinant Sendai virus vector in macaques

An efficient antigen expression system using a recombinant Sendai virus (SeV) has been established recently and its potential to induce resistance against immunodeficiency virus infections in macaques has been shown. SeV replication has been well characterized in mice, the natural host, but not in primates, including humans. Here, primary SeV replication was investigated in macaques. After intranasal immunization with a recombinant SeV expressing simian immunodeficiency virus Gag protein, SeV-Gag, robust gag expression was observed in the nasal mucosa and much lower but significant levels of gag expression were observed in the local retropharyngeal and submandibular lymph nodes (LN). Expression peaked within a week and lasted at least up to 13 days after immunization. SeV-Gag was isolated from nasal swabs consistently at day 4 but not at all at day 13. Gag expression was undetectable in the lung as well as in remote lymphoid tissues, such as the thymus, spleen and inguinal LN, indicating that the spread of the virus was more restricted in macaques than in mice. SeV-specific T cells were detectable in SeV-immunized macaques at day 7. Finally, no naive macaques showed significant levels of anti-SeV antibodies in the plasma, even after living in a cage together with an acutely SeV-infected macaque for 5 weeks, indicating that SeV transmission from SeV-infected macaques to naive ones was inefficient. None of the SeV-immunized macaques displayed appreciable clinical manifestations. These results support the idea that this system may be used safely in primates, including humans.

Evolution of the ABO blood group gene in Japanese macaque

We determined 5 sequences of Japanese macaque ABO blood group gene exon 7 (ca. 0.5 kb) and 2 sequences for exon 5 and intron 6 (ca. 1.7 kb). We compared those data with published sequences of other Old World monkey species, and the results suggest that alleles A and B were polymorphic in the ancestral species of macaques, and that B type allele evolved independently in macaque and baboon lineages.

Hematologic and plasma biochemical values for Tonkean macaques (Macaca tonkeana)

Hematologic and serum biochemical parameters were measured in 29 captive Tonkean macaques (Macaca tonkeana) to provide normative reference values for the species. Mean normal values and ranges were close to those reported in other species of macaques. Some significant variations related to age and sex were found.

Development of monkey C-reactive protein (CRP) assay methods

Monkey-specific C-reactive protein (CRP) assay methods (enzyme-linked immunosorbent assay (ELISA) and turbidimetric immunoassay (TIA)) were developed. The anti-monkey CRP serum was prepared by immunization of rabbits with the immune complex formed between the acute-phase serum from turpentine oil-inoculated monkeys and goat anti-human CRP serum. The specificity of the rabbit anti-monkey CRP serum was confirmed by immunoelectrophoresis and Western blotting. The purity of monkey CRP prepared by chromatography procedures was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The serum CRP levels in nine normal monkeys, as measured by sandwich ELISA were ranged from 0.26 to 1.42 microg/ml (mean 0.71+/-0.37). The CRP levels in five acute-phase sera of turpentine oil-inoculated monkeys were 248-451 microg/ml (mean 371.2+/-73.8). This monkey-specific CRP assay method was found more sensitive than the human-specific CRP assay method in detecting monkey CRP by TIA.

Plasma phospholipid mass transfer rate: relationship to plasma phospholipid and cholesteryl ester transfer activities and lipid parameters

Human plasma phospholipid transfer protein (PLTP) has been shown to facilitate the transfer of phospholipid from liposomes or isolated very low and low density lipoproteins to high density lipoproteins. Its activity in plasma and its physiological function are presently unknown. To elucidate the role of PLTP in lipoprotein metabolism and to delineate factors that may affect the rate of phospholipid transfer between lipoproteins, we determined the plasma phospholipid mass transfer rate (PLTR) in 16 healthy adult volunteers and assessed its relationship to plasma lipid levels, and to phospholipid transfer activity (PLTA) and cholesteryl ester transfer activity (CETA) measured by radioassays. The plasma PLTR in these subjects was 27.2 +/- 11.8 nmol/ml per h at 37 degrees C (mean +/- S.D.), and their PLTA and CETA were 13.0 +/- 1.7 mumol/ml per h and 72.8 +/- 15.7 nmol/ml per h, respectively. Plasma PLTR was correlated directly with total, non-HDL, and HDL triglyceride (rs = 0.76, P < 0.001), total and non-HDL phospholipid (rs > 0.53, P < 0.05), and inversely with HDL free cholesterol (rs = -0.54, P < 0.05), but not with plasma PLTA and CETA. When 85% to 96% of the PLTA in plasma was removed by polyclonal antibodies against recombinant human PLTP, phospholipid mass transfer from VLDL and LDL to HDL was reduced by 50% to 72%, but 80% to 100% of CETA could still be detected. These studies demonstrate that PLTP plays a major role in facilitating the transfer of phospholipid between lipoproteins, and suggest that triglyceride is a significant modulator of intravascular phospholipid transport. Furthermore, most of the PLTP and CETP in human plasma is associated with different particles. Plasma PLTA and CETA were also measured in mouse, rat, hamster, guinea pig, rabbit, dog, pig, and monkey. Compared to human, PLTA in rat and mouse was significantly higher and in rabbit and guinea pig was significantly lower while the remaining animal species had PLTA similar to humans. No correlation between PLTA and CETA was observed among animal species.

Normal serum biochemical and hematological values of the Sulawesi macaques

Sulawesi macaque (SM) species are currently of interest to primatologists for genetic and behavioral studies world wide. However, there are no published reference hematological and serum biochemical profile values for several of the seven SM species. Twenty-five clinically healthy, outdoor housed, ketamine sedated Macaca tonkeana and Macaca maurus were serially sampled (two to four times) over a 16-month period (N = 68). Normal ranges were defined to include two standard deviations and 2.5-97.5 percentile. Significant differences in single sample data comparisons (P < 0.05) of species (serum Ca, MCHC), age (BUN, BUN/creatinine, alkaline phosphatase, phosphorus), gender (total protein, RBC, hemoglobin, HCT) and pregnancy (phosphorus and neutrophil count) groups were found. This normative data facilitates clinical evaluation of SM species and allows comparison to other macaque species.

Infrequent shedding and transmission of herpesvirus simiae from seropositive macaques

The epizootiologic properties of Herpesvirus simiae (B virus) were studied in singly housed macaques (Macaca mulatta and M. fascicularis) in a biomedical vivarium to determine whether commonly encountered environments and procedures such as quarantine, breeding, Caesarean section, parturition, and social stress induced virus shedding and transmission. Macaques were tested serologically and for infectious virus. Oral, conjunctival, and vaginal swab samples were obtained repeatedly. Virus excretion was not detected during a 7-week quarantine of 32 newly acquired, singly housed animals tested every other week for 6 weeks, and none of 19 seronegative animals from this group seroconverted during 7 weeks in quarantine. No virus shedding was detected in 16 seropositive animals tested weekly for 3 weeks after Caesarean section or normal parturition or in 11 seropositive animals following introduction of new males to animals rooms. One animal seroconverted after repeated breeding of seropositive animals to seronegative partners. Fifty-three singly housed offspring remained seronegative for up to 10 years, even if born to seropositive dams, and only 1 of 86 singly housed animals less than 7 years old was seropositive. These results suggest that shedding of B virus from seropositive macaques is uncommon, when subjected to common laboratory procedures or environments, and that transmission is rare in singly housed animals. These results may be useful in establishing B virus-free colonies of macaques.

Production of stable rabbit-mouse heterohybridomas: characterization of a rabbit monoclonal antibody recognizing a 180 kDa human lymphocyte membrane antigen

Polyclonal rabbit antihuman thymocyte globulin (RATG) remains a key component of immunosuppressive strategies in transplantation. The human thymus immunization regimen that produces highly immunosuppressive RATG induces unique antibody specificities in the rabbit. Rabbit monoclonal antibodies (RAb MAbs) to human T cell antigens would be of value in the effort to investigate and reproduce the multiple specificities of RATG. We have fused mouse Sp2/0 cells with splenocytes from rabbits immunized with human thymus and have identified 52 rabbit-mouse heterohybridomas which secrete RAb MAbs directed against human lymphocyte surface antigens. The technical aspects of hybridoma isolation, stabilization and characterization are presented. Analysis by flow cytometry, preabsorption and immunoprecipitation suggests that RAb MAb 1A8 IgG may recognize LFA-1, one of the principal lymphocyte surface antigens recognized by RATG. The 1A8 antigen is 180 kDa and is expressed by 80-90% human PBL and thymocytes. LFA-1 and the 1A8 antigen exhibit 100% co-expression in two-color FACS analysis using four different murine anti-LFA-1 MAbs. 1A8 markedly inhibits the mitogenic response of lymphocytes to PHA, as do murine anti-LFA-1 MAbs. A combination of rabbit antilymphocyte MAbs may potentially reproduce the multiple specificities found in polyclonal RATG and lead to the production of a superior immunosuppressive clinical agent.

Role of glycated proteins in detecting and monitoring diabetes in cynomolgus monkeys

The use of glycated serum protein testing, as measured by serum fructosamine, to detect and monitor the diabetic state in 363 cynomolgus monkeys (Macaca fascicularis) consuming either standard diet or atherogenic diet was evaluated. Reference ranges were also established in 142 rhesus monkeys (M. mulatta) and 55 stumptail monkeys (M. arctoides). Values for serum fructosamine in all species ranged from approximately 0.5 to 2 mMol/liter. After determining the colony mean for each species and diet group, four cynomolgus monkeys were found to have serum fructosamine levels more than two standard deviations above the mean, whereas all values were normal in the rhesus and stumptail monkey colonies. These four animals were determined to be diabetic by repeated fasting glucose determinations and intravenous glucose tolerance testing. Serum fructosamine values correlated significantly with glycated hemoglobin (r = 0.61, P < 0.001) and fasting blood glucose (r = 0.70, P < 0.001) determinations in all diabetic and nondiabetic monkeys. The usefulness of serum fructosamine testing to monitor longitudinal glycemic control was also evaluated. Fasting blood glucose and fructosamine values for five previously diagnosed diabetic and five nondiabetic monkeys determined at 2-week intervals over a 20-week period correlated significantly (r = 0.75, P < 0.001). In conclusion, serum fructosamine may provide an objective parameter of antecedent glycemic control in nonhuman primates.

The Sulawesi Crested Black Macaque (Macaca nigra) menstrual cycle: changes in perineal tumescence and serum estradiol, progesterone, follicle-stimulating hormone, and luteinizing hormone levels

Events in the normal menstrual cycle of the endangered Sulawesi Crested Black Macaque (Macaca nigra) were characterized. Daily blood samples were obtained during 10 menstrual cycles from five M. nigra demonstrating regular cycles. The amount of perineal tumescence was scored daily. Serum levels of estradiol and progesterone were determined by RIA, serum LH levels were determined by the mouse Leydig cell bioassay, and serum FSH levels were determined by the rat granulosa cell aromatase bioassay. Cycle length was 39.8 +/- 1.0 days (mean +/- SEM) with an LH surge occurring 25 +/- 1.5 days from the onset of menses. After menses, both LH and estradiol were initially depressed, with estradiol first exceeding 50 pg/ml 8 days before the LH surge. In five cycles, peak estradiol levels (340 +/- 44 pg/ml) occurred on the day of the LH surge (637 +/- 58 ng/ml) and in the other five cycles, on the day before the LH surge. There was a broad increase of FSH in midcycle without a well-defined surge corresponding to the LH surge. Progesterone began increasing on the day of the LH surge and reached peak levels (6.8 +/- 0.96 ng/ml) 8 days later. Maximal perineal tumescence was generally associated with the time of the LH surge, but variation between animals made it impossible to predict accurately the day of the LH surge by perineal tumescence scores alone.

Effects of an intrauterine copper device on serum copper, endometrial histology, and ovarian, hepatic, and renal functions in the Japanese monkey (Macaca fuscata fuscata)

A copper intrauterine device (Cu-IUD) was inserted transabdominally into the uterine cavity of eight Japanese monkeys (Macaca fuscata fuscata) for 4 to 6 months, and effects on various organ functions were examined. Results showed no significant effects on the menstrual cycle length, serum levels of LH, estradiol-17 beta, progesterone or clinical biochemical data such as serum copper, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, lactic dehydrogenase, and blood urea nitrogen. Histology revealed edema and infiltration of eosinophilic leukocytes in the endometrium treated with a Cu-IUD.

[Periovulatory time courses of serum LH in the Japanese monkey (Macaca fuscata)]

Serum LH, E2-17 beta and progesterone concentration were measured in 16 cycles of 15 female Japanese monkeys. Three of the 16 cycles were ascertained to be anovulatory. Ten of the 13 ovulatory cycles showed LH peaks varying from 25 to 280 ng/ml. However, in remaining 3 cycles, LH peak could not be determined, probably because of a lag of blood-sampling schedule. E2-17 beta peaks were detected 0-30 hrs before LH peak in 8 cycles, but 13 or 20 hrs after LH peak in 2 cycles. Time-intervals from LH peak to ovulation ranged 0-47 hrs 30 min. No correlation was detected between concentrations of LH and progesterone in the luteal phase.

In vivo effects of recombinant human interleukin-6 in primates: stimulated production of platelets

In cynomolgus monkeys, twice daily subcutaneous injections of recombinant human interleukin-6 (rhIL-6) at doses of 5 to 80 micrograms/kg/d for 14 consecutive days caused dose-dependent increases in platelet count, usually continuing for more than 1 week after cessation of the injections. The count reached a level approximately twofold or more above the preinjection level even at 5 micrograms/kg/d, and at doses of more than 20 micrograms/kg/d, the increase became biphasic with a higher second peak 3 days after cessation of the injections. Morphologic analysis of the bone marrow after the 7 day-injections with 80 micrograms/kg/d revealed a marked increment in size of megakaryocytes compared with control, indicating the promotion of megakaryocyte maturation. Other changes attributable to the rhIL-6 treatment include dose-dependent loss of body weight, anemia, neutrophilia and monocytosis, elevation of serum C-reactive protein and alpha-1 acid glycoprotein levels, and decrease of serum albumin; all of which returned to normal within 1 week after cessation of the injections and were tolerable at doses of less than 10 micrograms/kg/d. These findings suggest that rhIL-6 may be an effective strategy for the treatment of thrombocytopenia.

Serum reference values of the Cynomolgus monkey, a model for the study of atherosclerosis

The usual biochemical parameters were evaluated in 19 Cynomolgus monkeys (male and female), receiving a normal balanced diet. The values were near those reported in man, although certain differences were observed.

Serological survey for two simian retroviruses in macaques and African green monkeys

Colonies of nonhuman primates at the Bowman Gray School of Medicine (BGSM) were tested for antibodies to two retroviruses associated with immunodeficiency by indirect immunofluorescence (IFA) and western blot. A total of 471 cynomolgus macaques (Macaca fascicularis), 144 rhesus monkeys (M. mulatta) and 67 stumptail monkey M. arctoides) were tested for SRV-1, and 152 African green monkeys (Cercopithecus aethiops) were tested for SIV. Of the macaques tested, 170 (36%) cynomolgus, 5 (3%) rhesus and 8 (12%) stumptails were positive for SRV-1 antibodies by IFA. Of the African green monkeys, 54 (36%) were IFA positive for SIV antibodies. A total of 143 African green monkeys tested by IFA also were tested by western blot. In the African green monkeys, the IFA had a positive predictive value of 98% and a negative predictive value of 96%. Of 176 IFA positive macaque sera tested by western blot, 49 (28%) were positive, 55 (31%) were considered equivocal (only one band, usually to p27 core protein), and 72 (41%) were negative.

[A comparison of hematological and serum biochemical values between two groups of female cynomolgus monkeys reared under different conditions]

The influence of long term rearing conditions on the hematological and serum biochemical values in laboratory-bred female cynomolgus monkeys (Macaca fascicularis) was studied under the following two conditions. Group A: New born infants were nursed by their mothers for at least 12 weeks after birth. After weaning, four monkeys of approximately equal age and body weight were kept in a relatively small cage (90 cm W x 60 cm D x 60 cm H) and reared to five years of age. These rearing conditions are commonly used in the breeding program of our primate center. Group B: One male and five females of wild origin were introduced into a relatively large cage (180 cm W x 180 cm D x 160 cm H). Female monkeys born in these cages were used in this study. All of them were reared by their own mothers and grew well in these cages. Male monkeys born in these cages were removed at about 3.5 years of age. Hematological and serum biochemical values between the two groups in each age class were compared and analyzed by the canonical discriminant analysis (the discriminant analysis with reduction of dimensionality). Age correlated highly with the value of the first canonical variate. The second canonical variate detected a difference in the blood hematology and biochemistry probably induced by the difference in rearing conditions.

[The information value of clinico-hematologic criteria for the early diagnosis of acute radiation sickness in pig-tailed macaques]

Ten pig-tailed monkeys (Macaca nemestrina) were subjected to 60Co radiation at a dose of 6.0-6.5 Gy and a dose rate of 1.2 Gy/min. Acute radiation sickness has developed in the monkeys causing their death on the 16-20 day. In spite of this, the initial reaction was weakly expressed and according to its manifestation it was impossible to evaluate severity and possible outcome of the lesion. At an early stage of the disease (6-24 hours) insufficient was uranin fluorescence in blood plasma, but more informative were the changes in adhesive properties of leukocytes the dynamics of lymphocytes (lymphopenia), reticulocytes (reticulocytopenia) and shifts in reticulograms (increased per cent of juvenile forms).

Antiandrogens do not reverse androgen-induced inhibition of sex hormone-binding globulin levels in adult female rhesus monkeys

Studies were done to determine if changes in plasma sex hormone-binding globulin (SHBG) levels could serve as a specific marker of androgenic and antiandrogenic activities in rhesus monkeys. Treatment of adult female monkeys for 11 days with 17 alpha-methyltestosterone (MeT) produced dose and time-dependent reductions in SHBG levels. However, the non-steroidal antiandrogen flutamide (80 mg/monkey.day) did not inhibit the reduction in SHBG levels when coadministered with MeT, nor did it have an effect on SHBG levels when given alone. In contrast, the steroidal antiandrogens Win 49596 (100 mg/monkey.day) and cyproterone acetate (80 mg/monkey.day) significantly (P less than 0.01) reduced SHBG plasma concentration to about 50% of pretreatment control values whether given alone or in combination with MeT. Furthermore, Win 49596 reduced SHBG levels at doses as low as 4 mg/monkey, whereas cortico-steroid-binding globulin levels were not affected. In ovariectomized monkeys, MeT treatment (4 mg/monkey.day for 15 days) reduced plasma SHBG levels to 42% of pretreatment values and delayed the onset of withdrawal menstrual bleeding compared to that in controls. When administered concurrently with MeT, flutamide (100 mg/monkey.day) antagonized the effect on withdrawal bleeding, but was without effect on SHBG levels. Therefore, plasma SHBG levels cannot be used as a specific indicator of androgenic or antiandrogenic activity and may not be regulated through the classical androgen receptor.

Circulating inhibin alpha concentrations in infant, prepubertal, and adult male rhesus monkeys (Macaca mulatta) and in juvenile males during premature initiation of puberty with pulsatile gonadotropin-releasing hormone treatment

Circulating inhibin alpha concentrations were determined in infant, juvenile, and adult male rhesus monkeys with a RIA employing antisera to a synthetic fragment of the alpha-subunit of porcine inhibin. Binding of tracer, [DSer1,Nle5]human inhibin alpha(1-25)-Gly-125I-Tyr, to antibody was inhibited by standard, [DSer1,Nle5]human inhibin alpha(1-25)-Gly-Tyr. and by plasma from adult male monkeys in a parallel fashion. Castration in adults resulted in a 5-fold decline in the levels of immunoreactivity in plasma. Mean (+/- SE) plasma inhibin alpha concentrations in infants and adults (322.9 +/- 51.9 and 460.1 +/- 43.9 pg/ml, respectively) were significantly higher (P less than 0.05) than those in juveniles (191.3 +/- 28.3 pg/ml). Moreover, initiation of puberty in juvenile males, 13-18 months of age, with a chronic (10- to 12-week) intermittent iv infusion of GnRH (0.1 microgram/min for 3 min every 3 h) resulted in a progressive rise in circulating inhibin alpha that plateaued, after 5 weeks of pituitary stimulation, at concentrations (343.9 +/- 38.2 pg/ml) comparable to those of infants and adults and twice those observed before initiation of the pulsatile infusion of GnRH. Circulating FSH concentrations increased during the first week of GnRH stimulation from 2.7 +/- 0.1 ng/ml before treatment to 6.0 +/- 1.2 ng/ml, where they remained for the duration of the experiment. Testosterone secretion during the initiation of precocious puberty occurred in discrete episodes that were robustly correlated with GnRH-induced LH discharges. In contrast, changes in circulating inhibin alpha concentrations over the 3-h interval between GnRH pulses were unremarkable. Activation of Sertoli and Leydig cells during initiation of puberty in the juvenile males, as reflected by circulating inhibin alpha and testosterone concentrations, respectively, occurred with similar time courses. At the time of orchidectomy, 10-12 weeks after initiation of GnRH treatment, testicular tissue was prepared for histological examination. In spite of a 2-fold gain in testicular weight and in hypertrophy of Sertoli cells in association with GnRH stimulation, maturation of the germinal epithelium did not progress past prophase I spermatocytes, and the number of these latter cells was meager. These findings indicate that the testis of the infant primate, like that of the adult, secretes significant amounts of inhibin, and that the quiescent Sertoli cell of the juvenile males may be readily provoked by appropriate gonadotropin stimulation into producing inhibin. The results also fail to provide evidence for the view that changes in circulating inhibin concentrations are robustly related, in an inve

Reference values of hematological, serum biochemical and hormonal examinations in female cynomolgus monkeys (Macaca fascicularis) of feral origin

Blood samples were collected from clinically healthy female cynomolgus monkeys imported from Indonesia, the Philippines and Malaysia. These animals were maintained under uniform environmental conditions for four to five years. The blood samples were examined for their hematological, serum biochemical and hormonal values. The ranges of the values as well as their arithmetic means and standard deviations have been tabulated with respect to each examination item.

Abnormalities in insulin secretion and glucose clearance among Macaca mulatta examined on Cayo Santiago

Macaca mulatta on Cayo Santiago (CS) were examined with intravenous glucose tolerance tests (IV-GTT) for evidence of abnormalities in glucose clearance and insulin secretion. About 10% of the 98 monkeys had impaired glucose clearance associated with impaired insulin secretion. Another 6% had either fasting or secretory hyperinsulinemia with slightly increased rates of glucose clearance, and 20% had low insulin secretion, but no significant changes in glucose clearance. Results were compared to those obtained with CS-derived monkeys tested at Sabana Seca (SS). Glucose clearance per amount of insulin secreted was 40% more effective among CS macaques than among those at SS. There were no differences in weight between impaired and control macaques on CS. Effects of genetics, physical activity, and food consumption can be studied among these macaques and results related to similar metabolic abnormalities in prediabetic and diabetic human beings.

Immunoreactive inhibin concentrations in serum throughout the menstrual cycle of the macaque: suppression of inhibin during the luteal phase after treatment with an LHRH antagonist

Concentrations of immunoreactive inhibin in serum samples collected daily from six adult stumptailed female macaques during normal menstrual cycles were measured with a heterologous radioimmunoassay. Serum inhibin concentrations were low during the follicular phase of the cycle. After ovulation they began to rise, reaching a plateau between 8 and 11 days, before falling in parallel with the decline in luteal progesterone secretion. The dependence of the inhibin secretion by the corpus lutem on pituitary gonadotrophins was investigated by the administration of an LHRH antagonist [N-Ac-D-Nal(2)1,D-pCl-Phe2,D-Trp3,D-hArg(Et2)6,D-Ala10 ]LHRH once daily for 3 days beginning on day 8 of the luteal phase in six macaques. LHRH antagonist treatment markedly suppressed serum levels of inhibin and progesterone and these remained at the level found in the follicular phase for the remainder of the luteal phase. These results show that inhibin in the macaque is secreted into the peripheral blood almost exclusively during the luteal phase, being highest when FSH is at its nadir. Suppression of serum inhibin concentrations during the luteal phase by LHRH antagonist suggests that its secretion is integrated with the LH control of the corpus luteum.

Studies on chorionic gonadotrophin hormone in rhesus monkeys--disappearance rates

The disappearance rate of macaque chorionic gonadotrophin (MCG) was investigated in six pregnant monkeys. The animals were hysterectomized with a rapid initial ligature of the uterine and ovarian vessels with minimal uterine manipulation. The entire procedure lasted less than 2 min. Blood samples were drawn before and after the hysterectomy (5, 20, 30, 45, 60, 90, 120 min), and MCG was measured in serum by radioimmunoassay. For all animals, a progressive decrease (rate of disappearance) of MCG values in serum was found, which appeared to follow a double exponential curve. Averaged curves produced disappearance rates of T1/2(1) = 17.2 h for the first compartment (72 h), and T1/2(2) = 87.1 h for the second compartment (156 h). The results suggest that the disappearance of MCG after interruption of pregnancy in rhesus monkey is very similar to that occurring in humans. These data demonstrate that the rhesus monkey is an excellent animal model to study the dynamics of placental hormone secretion in humans.

Novel hemoglobin components and their amino acid sequences from the crab-eating macaque (Macaca fascicularis)

We found two types of hemoglobin, T and R, from the crab-eating macaque and compared those to A and Q previously reported. The 22 animals studied showed six different phenotypes, A, R, QA, QT, QAT, and QAR. Analysis of the complete amino acid sequences for the alpha chains of hemoglobins Q, A, T, and R revealed that amino acids at four positions, 8, 55, 71, and 78 from the N-terminal, are variable. In the alpha A chain, Thr, Val, Gly, and Gln occupy these positions, and in the alpha Q chain the analogous amino acids are Thr, Val, Asp, and Gln, respectively. In the newly found alpha T chain they are Thr, Val, Gly, and His; and in the alpha R chain, they are Ser, Ile, Gly, and His, respectively. Two amino acids (alpha 8 Thr and alpha 78 Gln) in alpha A of the crab-eating macaque were found to be different from those in the alpha chain of the Japanese macaque.

[Discriminant analyses for pregnancy-related changes in hematological and serum biochemical values in cynomolgus monkeys (Macaca fascicularis)]

Hematological and serum biochemical data obtained from 45 non-pregnant and 142 pregnant cynomolgus monkeys (Macaca fascicularis) were analyzed by discriminant analyses. All animals used had been reared under uniform environmental conditions at Tsukuba Primate Center for Medical Science, N. I. H., Japan. The examination items were as follows: red blood cell count(RBC), hematocrit value(Ht), hemoglobin concentration(Hb), mean corpuscular volume(MCV), white blood cell count(WBC), total protein (TP), albumin (ALB), glucose (GLU), total cholesterol (TCHO), free cholesterol (FCHO), triglyceride (TG), and albumin-globulin ratio (A/G). The pregnant animals were divided into four groups according to their gestation ages (Group I: 1-40 days; II: 41-80 days; III: 81-120 days; and IV: more than 121 days). During pregnancy period (Groups II, III and IV), significant decrease of TP, ALB, TCHO, FCHO and TG was observed. RBC, Ht and Hb decreased in the last of the four periods of pregnancy (Group IV). Discrimination was possible between each of these four pregnant groups and the non-pregnant group on the basis of the Mahalanobis' generalized distance. To clarify the relationship among groups, canonical discriminant analysis (discriminant analysis with reduction of dimensionality) was carried out. As a result, the non-pregnant group and the pregnant I group could be clearly discriminated from the other pregnant groups (II, III, and IV) by the first canonical variate. Judging from the relative eigenvector value of each variable for the first canonical variate, the effective discriminant variables were RBC, Ht, Hb, MCV, TP and A/G.(ABSTRACT TRUNCATED AT 250 WORDS)

[Serum insulin concentration and arginine tolerance test in the cynomolgus monkey (Macaca fascicularis)]

The standard value of serum insulin was determined to be less than 75 microU/ml with ninety-eight female adult cynomolgus monkeys of wild origin. Then, fifteen apparently healthy laboratory-bred female cynomolgus monkeys aged 6-8 years were studied to know the usefulness of the arginine tolerance test (ATT) by measuring blood glucose, insulin and glucagon. Prior to ATT, all animals had been diagnosed as non-diabetic by the intravenous glucose tolerance test (IVGTT). Arginine hydrochloride was infused intravenously at a dose of 0.5 g/kg. BW under anesthesia. According to the standard value of insulin, fifteen animals were divided into two groups, that is, the low (n = 7) and the high (n = 8) value groups. In the low value group, glucose and insulin value did not change significantly after arginine infusion and their responses were similar to those in the control group (saline infused, n = 4). But glucagon markedly increased from 10 to 45 minutes post infusion. In the high value group, glucagon response was similar to that in the low value group, while glucose and insulin values significantly decreased. It is concluded that the pancreatic alpha-cell function (glucagon secretion) can be judged by the ATT in the cynomolgus monkey but the beta-cell function (insulin secretion) can not be diagnosed.

[Multivariate analysis of hematological and serum biochemical values in female cynomolgus monkeys (Macaca fascicularis) aged less than a year]

Hematological and serum biochemical data obtained from 91 laboratory-bred cynomolgus monkeys (Macaca fascicularis) aged 11 to 362 days were analyzed by the discriminant analysis. All animals used had been bred and reared under uniform environmental conditions at Tsukuba Primate Center for Medical Science, N. I. H., Japan. The examination items were as follows: red blood cell count (RBC), hematocrit value (Ht), hemoglobin concentration (Hb), mean corpuscular volume (MCV), white blood cell count (WBC), glutamic oxaloacetic transaminase activity (GOT), glutamic pyruvic transaminase activity (GPT), total protein concentration (TP), albumin concentration (ALB), albumin-globulin ratio (A/G), blood urea nitrogen (BUN), glucose concentration (GLU), total cholesterol concentration (TCHO), free cholesterol concentration (FCHO), triglyceride concentration (TG), alkaline phosphatase activity (ALP) and calcium concentration (Ca). The animals were divided into four groups (A: Suckling infants, less than 176 days old. B, C, D: Weanlings and juveniles, 121 to 220 days old, 221 to 280 days old, and 281 to 362 days old, respectively). Discrimination was possible among these four groups on the basis of the Mahalanobis' generalized distance. Regarding the canonical discriminant analysis (discriminant analysis with reduction of dimensionality), discrimination was possible. The suckling infant group could be discriminated from the juvenile groups by the first canonical variate. Concerning the juvenile groups, age was highly correlated to the value of the second canonical variate.2+ Judging from an approximate relative eigenvector value for the second canonical variate, the effective discriminant variables were WBC, TP, ALB, A/G, FCHO, TG, and ALP. It can be concluded that these eight parameters are important and useful for monitoring the physiologicals conditions of growing juvenile monkeys.

Cholesterol and dominance rank in the Cayo Santiago macaques

The relationship between serum total cholesterol (STC) and social dominance rank was investigated in adult (greater than or equal to 5 year old) males of a single, naturally-formed free-ranging troop of rhesus monkeys (Macaca mulatta) on Cayo Santiago, Puerto Rico. Dominance rank, age and body weight were not correlated with STC, nor was rank correlated with age or body weight. The mean (+/- 1 SD) STC was 154.0 +/- 27.0 mg/dl. Seven of the 34 males sampled had STC levels (189.1 +/- 4.3 mg/dl) greater than 1 SD above the mean for all males. These monkeys did not differ significantly in age or body weight from each other or the remaining males in the study, but 5 of the 7 monkeys with high STC were high-ranking in the group and 7 of 8 monkeys with STC (115.6 +/- 5.8 mg/dl) 1 SD or more below the mean for all males were low-ranking. The difference was significant (p less than .05, Fisher's Exact Test).