IgM-mesangial nephropathy in callithricids

Spontaneous IgM-mediated mesangioproliferative nephropathy was detected in 91% of tamarins and marmosets over 6 months old. The disease remains silent for long periods but is progressive. It is responsible for, or is at least related to, the cause of death in 20% of animals. Morphological characteristics are those of mesangial hyperplasia accompanied by subacute to chronic interstitial inflammation. The immunopathological demonstration of early accumulation of IgM within the mesangial cells and matrix, followed by interstitial deposition of C3, suggests that the lesion is mediated by immunological mechanisms.

[Spontaneous hepatitis similar to hepatitis A in African green monkeys]

Circulation of a virus similar to human hepatitis A virus by antigenic and some other properties was observed among African green monkeys imported from their natural habitats. In some of the monkeys this virus caused a disease similar to hepatitis A in many features.

[Spontaneous hepatitis A with a fatal outcome in rhesus monkeys]

This is the first report of virologically verified spontaneous hepatitis A in M. rhesus monkeys with severe involvement of the liver leading to the death of the animals. In 21 out of 23 dead monkeys morphological lesions in the liver have been characterized as acute hepatitis. In 6 (26%) animals no other pathological processes were found. In 15 animals hepatitis was combined with other diseases (dysentery, parasitic infestations, coronavirus infection). Antigen of hepatitis A virus was detected by an enzyme immunoassay in the intestinal contents of 8 monkeys and in the livers of 3 of them. Immune electron microscopic studies detected in the intestines some virus particles morphologically and antigenically similar to human hepatitis A virus.

Viremia, antigenemia, and serum antibodies in rhesus macaques infected with simian retrovirus type 1 and their relationship to disease course

The course of simian retrovirus type 1 (SRV-1) infection was studied in 14 experimentally inoculated juvenile rhesus monkeys. Viral transmembrane protein antigenemia and antibodies to whole virus were measured by enzyme linked immunosorbent assay and correlated with the clinical course of disease and virus isolation. Based on these parameters, animals with simian retrovirus type 1-induced disease were divided into three categories: monkeys dying within a few months of fulminating simian acquired immune deficiency syndrome in the face of a high level persistent antigenemia and viremia, and a nondetectable serum antibody response; monkeys that developed a milder form of simian acquired immune deficiency syndrome but remained alive in spite of a chronic low-grade antigenemia and viremia and only a transient initial antibody response; and monkeys that never became ill and that were either transiently or nontransiently viremic and antigenemic. This latter group developed high levels of serum antibodies. The outcome of simian retrovirus type 1-induced disease was similar to that described for feline leukemia virus infection of cats, another retroviral disease of animals. The disease course differed considerably, however, from that reported for retrovirus-induced human acquired immune deficiency syndrome.

Mycobacterium paratuberculosis infection in a colony of stumptail macaques (Macaca arctoides)

Mycobacterium paratuberculosis infection was documented in a colony of stumptail macaque monkeys (Macaca arctoides), with 29 (76%) of 38 monkeys infected and shedding organisms in feces. Thirteen deaths have occurred during the past five years. Animals without overt clinical disease were shedding as many as 2 X 10(6) colony-forming units of M. paratuberculosis/g of feces. Intestinal tissues from animals dying of this disease contained up to 10(8) colony-forming units of M. paratuberculosis/g of tissue. The clinical and pathological features of paratuberculosis in this species were comparable to those reported for paratuberculosis in ruminants and Mycobacterium avium infections in primates. By enzyme-linked immunosorbent assay, antibodies to M. paratuberculosis were found in 79%-84% of the animals. Antibodies could not be detected in six animals with clinical disease. These findings extend the natural host range of M. paratuberculosis to include nonhuman primates and add support to current suggestions that M. paratuberculosis may be pathogenic for humans.

STLV-I antibodies in feral populations of East African vervet monkeys (Cercopithecus aethiops)

Serum samples from feral populations of African green monkeys (Cercopithecus aethiops) were screened for antibodies to the simian T-lymphotropic virus, type I (STLV-I). Blood samples had been collected from 336 monkeys in 4 regions of central and southern Kenya in 1978 and 1979, from 114 monkeys in central Ethiopia in 1973, and from 85 monkeys from the Kampala region of Uganda in 1966. A total of 178/535 monkeys (33%) were seropositive (STLV-I+). Only 4/114 monkeys (4%) from Ethiopia were seropositive compared to 25/85 Ugandan monkeys (29%) and 149/336 Kenyan monkeys (44%). Epidemiological analysis of the Kenyan monkeys showed that 37% of the males and 54% of the females were STLV-I+, and that there was a progressive increase in the proportion of STLV-I+ monkeys of both sexes with age, rising from an average of 16% in infants (less than 9 months) to an average of 69% in adults (greater than 42 months). The proportion of STLV-I+ monkeys was higher among females in each age category. Seropositivity for antibodies to STLV-I had no apparent effect on the health of monkeys, and no association with the occurrence of Hepatocystis parasitemia was seen in this species. The analysis of data from infants of STLV-I+ mothers showed that seroconversion had occurred in 1 of 3 cases, suggesting that vertical transmission of the STLV-I virus is not an inevitable consequence for infants of seropositive mothers.

Neutralizing antibody prevents type D retrovirus viremia in Celebes black macaques

The Celebes black macaque (Macaca nigra) colony at the Oregon Regional Primate Research Center has a high incidence of simian acquired immunodeficiency syndrome (SAIDS-RF) that may be caused by type D retrovirus type 2 (SRV-2). During the spring and autumn screening of the colony, seven monkeys previously aviremic were found to be viremic on the basis of the Raji co-culture assay. These monkeys and control groups were selected for further study, which included titration of neutralizing antibody activity and immunofluorescent antibody (IFA) activity before and at the time that the animals became viremic. Results indicated that neutralizing antibody was not present before or at the time that monkeys became viremic and that control monkeys who were IFA+ and did not become viremic had high levels of neutralizing antibody. The IFA titre did not change significantly or predictably at the time the animals became viremic.

Neutralizing antibody in Celebes black macaques recovering from infection with simian acquired immunodeficiency syndrome retrovirus type 2

Neutralizing antibodies that block the ability of simian acquired immunodeficiency syndrome (SAIDS) retrovirus type 2 (SRV-2) to induce syncytium formation in cultures of Raji cells have been found in the serum of nonviremic Celebes black macaques (Macaca nigra). Serum from Celebes macaques that are viremic have little or no neutralizing activity. The neutralizing antibodies were shown to block viral infectivity. The group of monkeys with neutralizing antibodies in their serum exhibited a dramatic improvement in their health from 1982 to 1984. The correlation of neutralizing antibodies with clinical improvement suggests that neutralizing antibodies may play a critical role in limiting the pathogenic effects of SAIDS retrovirus infection and in helping eliminate the infection.

Lymphoproliferative syndrome in an immunodeficient rhesus monkey naturally infected with an HTLV-III-like virus (STLV-III)

A rhesus monkey with a naturally acquired STLV-III infection developed immunosuppression and a lymphoproliferative syndrome characterized by progressive lymphadenopathy and widespread visceral mononuclear cell infiltration. On microscopic examination, diffuse sheets of plasmacytoid lymphoblasts obliterated the sinuses and follicles of the nodes, replaced normal cellular elements of the spleen, bone marrow, and thymus, and infiltrated the lung, liver, kidney, salivary gland, pancreas, thyroid, stomach, and tongue. Immunohistologic studies indicated that the predominant cell in these infiltrates was a B lymphocyte, of oligo- or polyclonal origin. Similar but less extreme lymphoproliferative abnormalities were seen at necropsy in a substantial number of other animals with naturally occurring macaque immunodeficiency syndrome. The present case represents the first prospectively studied monkey with a naturally acquired simian T lymphotropic virus type III infection and illustrates an important manifestation of disease associated with such an infection.

Relationship of mitogen reactivity to type D retrovirus infection in Celebes black macaques (Macaca nigra)

The Celebes black macaque (Macaca nigra) colony at the Oregon Regional Primate Research Center has a high incidence of an immunodeficiency syndrome characterized by recurrent diarrhea and the development of retroperitoneal fibromatosis (RF). We have examined the relationship of type D viral infection to the immunodeficiency syndrome by surveying the colony for viral infection and for mitogen reactivity. Type D virus-positive monkeys (28% of the colony) have a higher prevalence of diarrhea, splenomegaly, lymphadenopathy and weight loss than do virus-negative monkeys, and RF has been found to occur only in virus-positive animals. Comparison of the concanavalin A (con-A) and phytohemagglutinin reactivities of the virus-positive and -negative populations has revealed no significant difference. However, within the virus-positive population, those with RF have reduced con-A reactivity and there are both high and low mitogen responders in the groups lacking RF. Thirty-two percent of the virus-positive monkeys are free of clinical symptoms, 40% have clinical symptoms but no RF, and 27% have clinical symptoms and RF. Five of the six monkeys with RF are older than the RF-free monkeys but monkeys are susceptible to type D retrovirus infection regardless of age or sex. The progressive nature of this immunodeficiency syndrome, its broad age range, and the probability that the etiological agent is also a type D retrovirus and the similarity of RF to Kaposi's sarcoma make this a potentially useful model for human AIDS.

Retroperitoneal fibromatosis and acquired immunodeficiency syndrome in macaques: clinical and immunologic studies

A simian acquired immunodeficiency syndrome (SAIDS) associated with retroperitoneal fibromatosis (RF) has been observed in several species of macaque at the Washington Regional Primate Research Center. Clinical signs were recurrent diarrhea, weight loss, mesenteric lymphadenopathy, and opportunistic infections. Most affected macaques in the later stages of illness showed marked immunodeficiency. Response of peripheral blood mononuclear cells to mitogens was impaired significantly. There was sharply depressed primary and secondary antibody response to the T-cell dependent antigen, bacteriophage phi X174. Affected monkeys did not switch from IgM to IgG antibody following a secondary immunization, as did normal macaques. Twenty-four (67%) of 36 affected animals with progressive RF or deteriorated stages of illness had hypoproteinemia and hypoalbuminemia. Quantitative serum immunoglobulins of 23 cases showed that eight (35%) had hypogammaglobulinemia, six (26%) had hypergammaglobulinemia, and the remainder (39%) were within the normal range. Opportunistic infections were predominantly bacterial pathogens. Type D retrovirus appeared to be closely associated with RF-affected macaques (12/12 or 100%). The case fatality rate (including animals sacrificed after prolonged illness) was 98%. The leading cause of death was due directly to RF lesions in 43%, to enterocolitis in 36%, septicemia in 12%, amyloidosis in 5%, and malignant lymphoma (2%). Clinical, immunologic and pathologic changes reveal an acquired immunodeficiency syndrome that has many similarities to human AIDS. SAIDS and RF may be a useful model for studying human AIDS.

Serological evidence for virus related to simian T-lymphotropic retrovirus III in residents of west Africa

Serological evidence is presented here suggesting that a virus closely related to simian T-lymphotropic virus type III (STLV-III) infects man in Senegal, west Africa, a region where AIDS or AIDS-related diseases have not yet been observed. 25 sera from Senegalese individuals that were positive for antibodies to HTLV-III by enzyme-linked immunosorbent assay were examined for antibodies to HTLV-III and STLV-III by western blotting. Sera from individuals originating from regions where AIDS has been reported, such as the United States and Burundi (central Africa), reacted best with antigens of HTLV-III, although antibodies that cross-reacted with STLV-III p24 were also detected. Conversely, sera originating from Senegalese people reacted better with STLV-III than with HTLV-III. This was exemplified by the absence of reactivity in sera from both monkeys and Senegalese people to p41, an antigen regularly detected by sera from antibody positive individuals originating from central Africa or from the United States. In contrast sera from central Africa or the United States did not react with p32, the putative envelope transmembrane protein of STLV-III that is regularly detected by sera from both monkeys and antibody-positive Senegalese people. These results suggest that certain healthy Senegalese people have been exposed to a virus that is more closely related to STLV-III than to HTLV-III. The existence and study of such virus variants potentially with differential pathogenicity may provide important information for the development of an AIDS virus vaccine.

Monocyte function in rhesus monkeys with simian acquired immune deficiency syndrome

Monocyte function in rhesus monkeys with simian acquired immune deficiency syndrome (SAIDS) was compared with that in age-matched normal juvenile rhesus monkeys. The functional tests were 1) chemotaxis, 2) phagocytosis of opsonized Candida albicans, 3) killing and/or growth inhibition of Candida albicans, 4) generation of respiratory burst, and 5) monocyte-derived macrophage response (morphology and/or respiratory burst) to stimulating agents such as lymphokines, gamma interferon, endotoxin, and phorbol myristate acetate. The monkeys tested had either clinical SAIDS (alive with lymphadenopathy, splenomegaly, and lymphopenia or neutropenia) or had terminal SAIDS (moribund due to the disease). Responses of monocytes from 14 monkeys with clinical SAIDS were indistinguishable from those of 9 normal juvenile rhesus monkeys, whereas monocytes from 3 monkeys with terminal SAIDS had enhanced phagocytosis and respiratory burst capacity. Chemotaxis, candidacidal/stasis activity, and response to stimulating agents were normal in these terminal cases. Plasma from the SAIDS monkeys was as capable of opsonizing yeasts and of being able to generate chemotactic factors by endotoxin as was control plasma. SAIDS retrovirus (SRV) was detected by co-cultivation of pure monocyte-derived macrophage cultures with Raji cells, an indicator cell line which forms syncytia in the presence of SRV. Four terminal SAIDS cases and one late-stage clinical SAIDS case were virus-positive when the number of macrophages in the cultures ranged from less than 50 to about 500. Terminal SAIDS monocyte-derived macrophages in culture as long as 17 days produced SRV. These data show that in monkeys with SAIDS the major effector functions of monocytes and macrophages involved in host defense are intact (even up until death). Additionally, some of the monocytes are productively infected, and these infected monocytes are viable and adherent in culture.

An immunopathologic evaluation of lymph nodes from monkey and man with acquired immune deficiency syndrome and related conditions

Morphology and immunostaining of lymph nodes taken from rhesus monkeys and man are compared. The monkeys were inoculated with biologic materials known to transmit simian acquired immune deficiency syndrome (SAIDS) and the human biopsies were obtained from homosexual men with persistent generalized lymphadenopathy syndrome or acquired immune deficiency syndrome (AIDS). The lymph nodes from monkey and man share common immunohistochemical features, ranging from exhuberant follicular hyperplasia to lymphocyte depletion stage. The follicular hyperplasia differed from reactive controls by the larger follicular size and disorganization within the follicular centers as well as an increase in the number of cells with the T suppressor/cytotoxic phenotype. The lymphocyte depletion stage showed a loss of reactive follicles and small T lymphocytes with a predominance of mature monocytes/macrophages. Most monkeys and humans with the lymphocyte depletion morphology fulfilled the case definitions for AIDS and SAIDS while those with follicular hyperplasia usually had 'prodromal' findings. The simian agent is associated with alterations in lymph node morphology and immunostaining which parallel the changes seen in spontaneous human cases supporting a similar pathogenesis for AIDS and SAIDS.

Immunologic alterations in monkeys with simian acquired immunodeficiency syndrome (SAIDS)

Levels of lymphocyte responsiveness to T- and B-cell-specific mitogens and expressions of Ia, T4, T8, and T11 surface markers were monitored during the course of Simian acquired immunodeficiency syndrome (SAIDS) in four Rhesus macaques that either died or became ill and survived. The monkey that died showed progressively suppressed responses to concanavalin A (Con A), phytohemagglutinin (PHA), pokeweed mitogen (PWM), and Staphylococcus aureus Cowan I strain (SAC) through the time of death (5 1/2 weeks). For the three animals that survived, the responses of peripheral blood mononuclear cell (PBMC) to the same mitogens were decreased significantly during the period 4-6 weeks after inoculation. Levels of Ia-bearing cells in the PBMC population were markedly reduced in the moribund monkey but were not significantly decreased in the three survivors. There was no significant change in the percentage of T11-bearing cells in any of the study animals. The ratio of T4- and T8-positive cells did not vary significantly during the 18 weeks of observation in any of the animals. The infected animals showed other evidence of immunosuppression including neutropenia, lymphopenia, and depletion of lymphocytes in lymph nodes. The animal that had progressive disease and death also had Kaposi-like lesions and staphylococcal septicemia. These results indicated that in vitro evidence of immunosuppression due to SAIDS appears within a few weeks after infection and this may progress in animals that die.

Virus-associated deficiencies in the mitogen reactivity in celebes black macaques (Macaca nigra)

Celebes black macaques (Macaca nigra) with a history of diabetes mellitus, recurrent bacterial and protozoal infections, diarrhea, anemia, weight loss, anorexia, and a high mortality were studied to determine their immune status. Two groups of monkeys, healthy and unhealthy, were formed on the basis of a clinical assessment. The proliferative response and the pokeweed-mitogen-induced polyclonal IgG response of peripheral blood mononuclear cells of unhealthy monkeys were significantly less than the responses of healthy monkeys. The percentage of HLA-DR+ cells varied greatly in unhealthy monkeys. The OKT4/OKT8 ratios of unhealthy monkeys were generally greater than the ratios of healthy monkeys. Unhealthy monkeys usually had smaller percentages of OKT8+ cells than did healthy monkeys. The two groups of monkeys were examined for the presence of a syncytial forming retrovirus by a coculture assay involving Raji cells, a human B lymphoblastoid cell line. A type D retrovirus was detected in the unhealthy group but not in the healthy group. Retroperitoneal fibromatosis was detected in several monkeys in the unhealthy group.

Immunoprecipitation of Epstein-Barr virus (EBV)-specific proteins by prelymphomatous and normal baboon sera containing antibodies reactive with EBV early antigen

Carbon (14C)-amino acid mixture-labelled antigen extracted from 12-0-tetradecanoyl-phorbol-13-acetate (TPA) and sodium n-butyrate-induced P3HR-1 cells was immunoprecipitated with sera from normal, prelymphomatous and lymphomatous baboons, as well as with sera from human controls. Most of the Epstein-Barr virus (EBV)-specific proteins that were precipitated by human sera were also precipitated by baboon sera. A major difference between prelymphomatous and normal control baboon sera was that 5 out of 6 the former and none of the latter immuno-precipitated an EBV-early antigen-specific protein with Mr 31,000.

Immunologic abnormality in a group of Macaca arctoides with high mortality due to atypical mycobacterial and other disease processes

Of 54 Macaca arctoides, 44 died during the 2.5 years after their assignment to a common cage. Although early deaths were due to trauma, acute gastric dilatation, and shigellosis; latter deaths were the result of a variety of uncommon diseases including atypical mycobacterial disease, malignant lymphoma, protozoan encephalomyelitis, and other necrotizing and inflammatory lesions. Atypical mycobacterial disease due to Mycobacterium avium intracellular serotypes was the most frequent single disease agent recognized (33% [18 macaques]). This disease began in the ileum and large intestine with subsequent systemic involvement. An abnormality of host response to infective agents, in general, was indicated by the unusually high occurrence of this disease, as well as other disease processes. Morphologic evaluation of lymphoid organs revealed decreased cellularity of follicles and decreased numbers of plasma cells in all macaques, whereas T cell-dependent areas varied from hypocellular to hypercellular with 5 macaques with malignant lymphoma. The spontaneous erythrocyte rosette-forming subpopulation of T cells was decreased in peripheral blood, but was increased in lymph nodes containing atypical mycobacterial lesions. Serum immunoglobulin value decreased progressively in diseased macaques. A basic abnormality of T-cell subpopulations controlling other components of host response was suspected. Macrophages from lesions that contain mycobacterial organisms did not phagocytize latex beads normally in vitro, whereas monocytes in the blood of the same macaques were capable of in vitro phagocytosis.

Leprosy in a mangabey monkey--naturally acquired infection

Naturally acquired leprosy was detected in an otherwise normal "sooty" mangabey monkey (Cercocebus atys). This animal was imported from West Africa in 1975 and developed clinical symptoms of leprosy in 1979. Histopathologic findings were those of subpolar-lepromatous to borderline-lepromatous leprosy in the Ridley-Jopling classification. The disease was progressive, with crippling neuropathic deformities of the hands and feet. The disease regressed under specific therapy. The etiologic agent was identified as Mycobacterium leprae by the following criteria: invasion of nerves of host, staining properties, electron microscopic findings, noncultivable on mycobacteriologic media, DOPA-oxidase positive, lepromin reactivity, infection patterns in mice and armadillos, sensitivity to sulfone, and DNA homology. We believe the animal acquired the disease from a patient with active leprosy. The mangabey monkey offers promise as a primate model for leprosy, and adds a third reported species to animals with naturally acquired leprosy.

Immune defects in simian acquired immunodeficiency syndrome

We recently reported a Simian Acquired Immunodeficiency Syndrome (SAIDS) in rhesus macaques at the California Primate Research Center. Here, we studied in vitro lymphocyte response to the mitogens Concanavalin A (Con A), phytohemagglutinin (PHA) and pokeweed mitogen (PWM) with and without interleukin 2 (IL-2). Immunoglobulin (IgG and IgM) and complement (C3 and C4) concentrations were determined by radial immunodiffusion. T helper and T suppressor lymphocytes were identified with the monoclonal antibodies OKT4 and OKT8. Concentrations of IgG and IgM were significantly (p less than .05) decreased. Complement component C3 did not change but C4 was increased. The absolute lymphocyte count decreased but the OKT4:OKT8 ratio was unchanged from controls. A decreased lymphocyte response to all mitogens occurred early and became more severely depressed near death. IL-2 caused a complete or partial restoration of the response to the mitogens CON A and PHA. Both the humoral and cell mediated immune responses are affected in SAIDS. The role of IL-2 in this immune defect must be studied further.

Immunopathology associated with human lymphotropic retroviruses

The human lymphocytotropic retroviruses, despite the fact that their immunopathology varies from acute immunodeficiency to leukemia, have several features in common: they are exogenous viruses isolated from mature T cells, especially T4+ T-cells; they preferentially infect mature T4+ T cells in vitro, although other kinds of cells can be infected (no pathologic effects have been associated with infection of nonlymphoid cells); they possess a reverse transcriptase with similar size and preference for Mg++; they have a unique pX sequence in their genome which codes for a protein which is responsible for trans-activation of viral and possibly cellular genes, and in vitro infection of some T cells induces either continuous proliferation or cytotoxicity which mimic the in vivo manifestations of the virus.

Depression of lymphocyte responses to mitogens in mangabeys with disseminated experimental leprosy

Mononuclear cells from mangabey monkeys with disseminated experimental leprosy had increasingly severe depression of blastogenic responses to phytohemagglutinin, concanavalin A, and pokeweed mitogen as the disease progressed. Blastogenic responses were not depressed in cells from mangabeys with more localized disease. Blastogenic responses of cells from normal mangabeys appeared to vary with a circannual rhythm. The demonstration of significant negative correlations between the blastogenic responses to mitogens and the percentages of OKT8+ cells suggested that the mangabey OKT8+ subset may contain cells with suppressor function. The depressed responses to mitogens by cells from monkeys with disseminated experimental leprosy were associated with relatively high percentages of OKT8+ cells. Polyclonal immunoglobulin plaque-forming cell responses to pokeweed mitogen were depressed in cells from experimentally infected mangabeys. The results indicated that defects in immune regulation may occur in experimental leprosy in mangabeys, similar in some respects to the defects that have been reported in human leprosy.