Induction of AIDS-like disease in macaque monkeys with T-cell tropic retrovirus STLV-III.

The T-cell tropic retrovirus of macaque monkeys STLV-III has morphologic, growth, and antigenic properties indicating that it is related to HTLV-III/LAV, the etiologic agent of the acquired immune deficiency syndrome (AIDS) in humans. Four of six rhesus monkeys died within 160 days of STLV-III inoculation with a wasting syndrome, opportunistic infections, a primary retroviral encephalitis, and immunologic abnormalities including a decrease in T4+ peripheral blood lymphocytes. These data show that an immunodeficiency syndrome can be produced experimentally in a nonhuman primate by an agent from the HTLV-III/LAV group of retroviruses. The STLV-III-macaque system will thus provide a useful model for the study of antiviral agents and vaccine development for human AIDS.

Effect of dietary fat saturation on plasma lipoproteins and high density lipoprotein metabolism of the rhesus monkey.

Rhesus monkeys were fed corn or coconut oil-based diets for 3-6 mo to determine effects on the composition of all lipoprotein classes and on the metabolism of high density lipoproteins (HDL). Major findings included the following. Coconut oil feeding increased concentrations of all classes of plasma lipoproteins without altering lipoprotein size, suggesting an increase in particle number. The percentage of saturated fatty acids in the cholesteryl esters (CE) of low density lipoproteins (LDL) and HDL reached 40% with coconut oil feeding. This value probably constitutes a minimum estimate of the CE which were of intracellular rather than intraplasmic origin. The CE in LDL and HDL were nearly identical suggesting virtually complete equilibration by the core lipid transfer reaction. The CE in very low density lipoproteins, in contrast, were significantly more saturated than those in LDL and HDL irrespective of diet. Lower HDL levels on the corn oil diet were associated with higher fractional catabolic rates for both apolipoprotein A-I (0.42 vs. 0.31 d-1) and apolipoprotein A-II (0.45 vs. 0.30 d-1).

Effectiveness of remifentanil versus traditional fentanyl-based anesthetic in high-risk outpatient surgery.

STUDY OBJECTIVE: To determine if remifentanil would offer a superior hemodynamic and recovery profile compared to the current standard of care, which implements a fentanyl-based technique. DESIGN: Randomized, single-blind study. SETTING: Outpatient center associated with tertiary care center. PATIENTS: 75 outpatients undergoing microsuspension laryngoscopy. INTERVENTIONS: Patients were randomized to either a remifentanil induction (0.5 microg/kg/min) and maintenance (0.25 microg/kg/min) versus fentanyl (maximum of 250 microg) as the only opioid. All patients received propofol as part of the induction and maintenance with or without the use of nitrous oxide. MEASUREMENTS: Assessment of hemodynamics [heart rate (HR) and blood pressure(BP)], presence of perioperative myocardial ischemia on ambulatory electrocardiographic monitoring, and time to discharge. MAIN RESULTS: Significantly fewer patients in the remifentanil group demonstrated episodes of tachycardia (HR > 100 beats per min) compared to the fentanyl group (14% vs. 40%, p<0.05), with significantly fewer episodes of tachycardia and hypertension per patient. Recovery profiles between the two groups did not show clinically significant differences. CONCLUSIONS: Remifentanil, a new short-acting opioid, offers excellent hemodynamic control for brief, intense outpatient procedures performed in high-risk patients; however, its use was not associated with any improvement in recovery profiles.

A sparsely granulated, nonsecreting adenoma of the pars intermedia associated with galactorrhea in a male rhesus monkey (Macaca mulatta).

A pituitary mass was found at necropsy of a male Macaca mulatta. Hematoxylin and eosin-stained sections were consistent with a chromophobe adenoma. Ultrastructural examination revealed the tumor to be comprised predominantly of sparsely granulated cells. The tumor cells were negative for prolactin, somatotropin, adrenocorticotropin, luteinizing hormone, and thyrotropin by the peroxidase anti-peroxidase method. Other major lesions were gynecomastia and galactorrhea, testicular atrophy, ankylosing spondylitis, and amyloid deposition in the liver, spleen, adrenal, and intestinal tract.

The female genital tract of the owl monkey (Aotus trivirgatus) with special reference to the ovary.

The female reproduction tracts and ovaries of 30 owl monkeys, Aotus trivirgatus, were examined morphologically using the light and electron microscope. The animals ranged in age from a third trimester stillborn fetus to those of mature old age. The epithelia of the generative tracts were inactive or resting; evidence of prior menstruation was occasionally evident from hemosiderosis in endometrial stroma. Cyclicity of estral or menstrual type, however, was not established. One pregnant uterus (11-12 days gestation) was in the series. Prior pregnancy was deduced by the presence of perivascular fibrosis of myometrial vessels. The immature ovary contained an occasional developing or involving Graafian follicle, but no interstitial tissue. The mature ovary developed large, multilobulated masses of luteinized interstitial tissue which occupied the medulla, crowded the hilum, and thinned the cortex. Small dark intracortical cells, derived from cortical stroma, became foamy, lipoid-laden, contained hemofuscin, and formed the peripheral zone of the interstitial cell masses. The theca interna of involuting follicles appeared to be a significant source of the inner cells of the interstitial masses. Ultrastructure of the outer pigmented cells of luteal interstitial masses suggested steroidal activity; the function of the inner cells was not morphologically evident. Corpora lutea could not be identified with certainly, either by form, stigmata, or histology; nor could they be differentiated from interstitial masses. The latter appeared, therefore, to act in concert as a single, massive bilateral corpus luteum.

Dysplasia of the lower genital tract in the female monkey, Macaca fascicularis, the crab-eating macaque from Southeast Asia.

Seventy-eight female reproductive tracts from mature Macaca fascicularis caught in the wild were examined histologically for evidence of dysplasia in immature (metaplastic) and native (mature) squamous epithelium of the cervix and vagina. This series contained equal numbers of experimental animals and control and/or breeding colony animals. Five of 39 experimental animals showed dysplasia, whereas six animals with definite and two with questionable dysplasia were found in 39 control and breeding colony animals. On the basis of the foregoing facts, it would appear that these dysplastic lesions were of spontaneous origin and of undetermined etiology. Therefore, those investigators who experiment upon the reproductive tract of this species of monkey should be wary of interpreting any given experiment as "causing" dysplasia. Monkeys of this same species, born and reared in our Primate Center, have been examined for comparable dysplastic lesions of the lower female genital tract. None was found thus far but the study is continuing.

Immunoglobulin-A nephropathy with crescentic glomerulonephritis in a pigtailed macaque (Macaca nemestrina).

A 4-year-old female pigtailed macaque (Macaca nemestrina), experimentally coinfected with simian immunodeficiency virus (SIVmac251) and Mycobacterium bovis(bacillus Calmette-Guerin), was euthanatized 1 year after infection because of weight loss and labored breathing. On gross examination, both kidneys were found to be markedly enlarged (right: 54.7 g and left: 51.7 g; normal < 20 g). Renal lesions were evaluated by histopathologic, immunohistochemical, and ultrastructural methods. Light microscopy revealed that the glomeruli were diffusely hypercellular with expansion of the mesangial matrix, and crescent formation affected approximately 60% of the glomeruli. By immunohistochemical evaluation, it was found that the crescents were composed principally of macrophages, as seen by CD68 (KP1), MRP8, MAC387, and HAM56 expression. Electron microscopic examination of the glomeruli revealed extensive intramembranous, subendothelial, and mesangial electron-dense deposits and multifocal fusion of the visceral epithelial foot processes. Immunofluorescence, used to determine the composition of the electron-dense deposits, revealed diffuse granular mesangial and capillary staining for immunoglobulin A (IgA). The renal changes described in this case report are most consistent with the findings of crescentic gloerulonephritis with IgA immune complex deposition in the glomerular basement membrane and mesangium as described in humans with IgA nephropathy.

Arteriopathy in macaques infected with simian immunodeficiency virus.

BACKGROUND: An arteriopathy characterized by intimal and medial thickening and fibrosis was seen in 19 of 85 rhesus monkeys infected with simian immunodeficiency virus (SIV), a lentivirus with morphologic, genetic, and biologic similarities to HIV-1 and HIV-2. EXPERIMENTAL DESIGN: All cases of simian AIDS in rhesus monkeys at the New England Regional Primate Research Center, resulting from either experimental or naturally acquired SIV infection, were retrospectively examined for evidence of histopathologic changes to the vasculature. Of the 85 SIV-related deaths recorded in the pathology files to date, tissues from 19 animals were chosen for further study because of thickening, disruption, inflammation, or other abnormality to any layer of the vascular wall. The lesion was characterized by special stains, immunoperoxidase procedures, and ultrastructural examination. RESULTS: Affected monkeys of both sexes varied in age from 4 months to 17 years at the time of inoculation and survived from 41 days to 4 years after infection. Pulmonary arteries were affected in all 19 animals, while vessels in other parenchymal organs were involved less frequently. In addition to sometimes marked intimal thickening with luminal occlusion, the internal elastic laminae were fragmented and interrupted. Seven of 19 animals had pulmonary thromboses with varying degrees of organization and recanalization. Immunohistochemical studies, special stains, and ultrastructural analyses revealed the thickened intimae to be composed predominantly of collagen, extracellular matrix, and smooth muscle cells. Ultrastructurally, endothelial cells from both early (no intimal thickening) and advanced lesions were plump, vacuolated, and often disorganized and detached from the subendothelial space. Increased numbers of macrophages (CD68+) were found in the adventitia and occasionally in the thickened intima and media. Rare, fully differentiated macrophages (CD68+, 25F9+) were demonstrated in lumina of affected vessels, some of which expressed p27 SIV gag protein. However, the lesion was not uniformly associated with localization of either viral protein or RNA at the site using immunohistochemistry or in situ hybridization, respectively. A similar arterial lesion has been described in children with AIDS. CONCLUSIONS: The morphologic findings in macaques and their similarity to arteriosclerotic changes induced by experimental endothelial damage in other species collectively suggest that arteriopathy in AIDS may represent a manifestation secondary to primary endothelial injury.

Glomerulonephritis in the owl monkey (Aotus trivirgatus): ultrastructural observations.

The kidneys of 11 clinically healthy owl monkeys (Aotus trivirgatus) acquired from four different sources were examined by light and electron microscopy. Eight of the 11 animals had morphologic evidence of glomerulonephritis. The lesions were characterized by one or more of the following changes: focal or segmental thickening of the glomerular basement membrane; proliferation of mesangial cells with increased production of mesangial matrix; and fibrosis and hyalinization of glomeruli with and without inflammatory cellular infiltration. Five of the eight animals with one or more of the above described changes had electron-dense deposits compatible with immune complex deposits in the intra-membranous and subepithelial regions of the basement membrane. The nature and source of the antigen or antigens responsible for the lesions are unknown.

Immunophenotypic characterization of mononuclear phagocytes and dendritic cells in lymphoid organs of the rhesus monkey.

Mononuclear phagocytes and dendritic cells are potent antigen-presenting cells that localize to distinct microenvironmental compartments in many different organs. These cells are particularly plentiful in spleen and lymph node. Recently, these cells have been identified and immunophenotypically characterized in human tissue sections using monoclonal antibodies. However, similar studies in animal species, particularly those representing models of human diseases, have yet to be completely performed. We have evaluated 18 monoclonal reagents raised against human determinants for their reactivity with macrophages and dendritic cells in lymphoid organs of rhesus monkeys. Six of the 18 (EBM11, 25F9, Mol, R4/23, To5, and SK9) produced labeling patterns in rhesus monkey lymphoid tissue that paralleled the staining patterns described for human tissues. Seven others (KB90, FMC17, Mo3, PHM3, PHM2, G16/1, and 27E10) stained varying subsets of specific cells types in these simian tissues. These reagents are requisite for the future study in an experimental animal of the afferent immune response in both normal and disease states.

Cytokine influence on simian immunodeficiency virus replication within primary macrophages. TNF-alpha, but not GMCSF, enhances viral replication on a per-cell basis.

The control of HIV-1 or SIV replication within macrophages is probably influenced by a variety of viral and cellular factors. Of the cellular factors, the authors have studied cytokine influence on SIV replication in vitro utilizing simian alveolar macrophages and uncloned SIVmacMTV, a macrophage-tropic variant. The approach allowed quantification of viral replication on a per-cell basis. As reported for HIV-1 replication in macrophages, TNF-alpha significantly increased SIV production in these macrophage cultures. GMCSF also resulted in marked increases in SIV gag protein in culture supernatants. However, after correcting for differences in total cell numbers and numbers of gag-containing cells in the treated and untreated cultures, GMCSF did not upregulate SIV production on a per-cell basis. IL-6 increased SIV replication little if at all but induced significantly greater cytopathic changes in the treated cultures compared with infected, untreated cultures. In contrast, IFN-gamma greatly decreased replication. Our results for GMCSF, IFN-gamma, and IL-6 are in contrast to previously published reports of cytokine control of HIV-1 growth in target cells, and they stress the importance of cell number analyses and the use of primary cultures in the study of lentiviral replication kinetics in macrophages.

Acute fulminant sarcocystosis in a captive-born rhesus macaque.

A captive-born juvenile female rhesus macaque (Macaca mulatta) was acquired from a commercial breeder and placed in quarantine. Within 8 days of arrival, the animal became anorexic, inactive, and dehydrated. Subsequently, generalized edema and facial ecchymoses developed, and despite supportive therapy, the animal became moribund and was euthanatized. Macroscopic examination showed diffuse stippling and streaking of the myocardium. Histopathologic examination revealed multifocal to coalescing myocardial edema, necrosis, lymphohistiocytic inflammation, and generalized endothelial infection with Sarcocystis sp. Immature and mature schizonts within endothelial cells were most prevalent in the heart. Fewer schizonts were present in the vasculature of other tissues, including skeletal muscle, smooth muscle, adipose tissue, brain, and retina. Mature tissue cysts within muscle fibers were not found in the myocardium but were occasionally seen in skeletal muscle. Analysis of polymerase-chain-reaction-amplified 18s ribosomal RNA gene sequences revealed 96% identity to published sequences of S. hirsuta, S. hominis, and S. fusiformis and 95% identity to S. cruzi and S. tenella. However, sequences did not show complete identity with any organism in the GenBank database. Sequence homology suggests that this is a newly described Sarcocystis sp. Results of antibody tests for simian retrovirus, simian T-lymphotropic virus 1, and simian immunodeficiency virus were negative, suggesting that viral immunosuppression was unlikely to have augmented the pathogenicity of sarcosporidial infection. Clinical and histopathologic findings in this case of fulminant sarcosporidiosis are similar to those described in Dalmeny disease in cattle, which is associated with ingestion of massive numbers of infective Sarcocystis oocysts.

Expression of peripherin in the brain of macaques (Macaca mulatta and Macaca fascicularis) occurs in astrocytes rather than neurones and is associated with encephalitis.

Peripherin is a member of the type III intermediate filament family, expressed in neurones of the peripheral nervous system of many species and in a discrete subpopulation of neurones of the central nervous system (CNS) during early development in rodents. Previous studies on rats have shown that peripherin immunoreactivity increased significantly in cell bodies of spinal motor neurones following axonal injury. Our study examined the expression of peripherin in the cerebrum of normal macaques (Macaca mulatta and Macaca fascicularis) and those with encephalitis of viral (simian immunodeficiency virus and simian virus 40) or autoimmune (experimental allergic encephalomyelitis) aetiology. Immunohistochemistry, immunoelectronmicroscopy, immunofluorescence and confocal microscopy were performed on tissue sections using antibodies against cell-specific markers and peripherin. Peripherin-positive cells were absent in the cerebrum of normal macaques of all ages examined, whereas animals with encephalitis had peripherin-positive cells associated with inflammatory infiltrates. Further evaluation revealed that these peripherin-positive cells were not neurones, but were predominantly astrocytes expressing glial fibrillary acidic protein. Our study suggests that peripherin is not neurone-specific in the CNS of macaques; peripherin is expressed in astrocytes of animals with encephalitis.

A case of pulmonary cestodiasis in a simian immunodeficiency virus-infected pigtailed macaque (Macaca nemestrina) in which virus-infected leukocytes are present within the lesion.

The larvae of Mesocestoides are rarely encountered in nonhuman primates, with most cases reported in baboons. Infection of macaques has been occasionally diagnosed, but Mesocestoides in the lung parenchyma is extremely rare. We have previously demonstrated that in macaques with terminal AIDS, simian immunodeficiency virus (SIV)-infected leukocytes are rarely found in cellular infiltrates associated with opportunistic infections or preexisting disease. Here we describe larvae (tetrathyridia) of the cestode Mesocestoides in the lung of an adult, pigtailed macaque (Macaca nemestrina) during acute SIV infection in which virus-positive cells are present within the cellular infiltrates. These results describe a rare parasitic disease in pigtailed macaques and demonstrate that lentivirus-infected leukocytes can be associated with inflammatory sites during acute infection.

A chimpanzee-passaged human immunodeficiency virus isolate is cytopathic for chimpanzee cells but does not induce disease.

The human immunodeficiency virus type 1 (HIV-1) readily infects both humans and chimpanzees, but the pathologic outcomes of infection in these two species differ greatly. In attempts to identify virus-cell interactions that might account for this differential pathogenicity, chimpanzee peripheral blood lymphocytes and bone marrow macrophages were assessed in vitro for their ability to support the replication of several HIV-1 isolates. Although the IIIb, RF, and MN isolates did not readily infect chimpanzee peripheral blood lymphocytes, an isolate of HIV-1 passaged in vivo in chimpanzees not only replicated well in both chimpanzee peripheral blood lymphocytes and bone marrow macrophages but also was cytopathic for chimpanzee CD4+ lymphocytes. Because no evidence of HIV-induced disease has been observed in chimpanzees infected with this isolate, in vitro replication to high titers with concomitant loss of CD4+ cells is not, in this instance, a correlate of pathogenicity. These observations, therefore, indicate that caution must be used when making extrapolations from in vitro data to in vivo pathogenesis.

Study of long-term cultures of simian immunodeficiency virus (SIVmac 251)-infected peripheral blood lymphocytes.

A culture of rhesus monkey peripheral blood lymphocytes was divided into two parts; one was kept as an uninfected control, and the other was infected with a strain of simian immunodeficiency virus (SIVmac251) originally isolated from a rhesus monkey that died of a malignant lymphoma associated with acquired immune deficiency syndrome. Both cultures were sampled at successive intervals from 1 to 40 days postinfection. Each sample was subjected to in situ hybridization for detection of viral mRNA, immunocytochemical detection of viral core protein (p27), reverse transcriptase assay, electron microscopy, and immunophenotypic characterization of infected cells. These techniques were used to define viral growth kinetics of this novel lentivirus in peripheral blood lymphocytes. The first evidence of SIVmac251 replication was obtained by an in situ hybridization signal for viral mRNA at 2 days postinoculation. This was followed by detection of viral p27 core protein by immunocytochemistry on day 4. Reverse transcriptase activity above control values was not detected until day 8. Budding particles were not found in the infected cultures until 14 days postinfection. Results of in situ hybridization, immunocytochemistry, and reverse transcriptase assay indicated that two bursts of viral replication occurred during the course of this study. The first, at 3 weeks postinfection, was due to infection and subsequent depletion of CD4+ lymphocytes, while the second, 3 weeks later, resulted from a cycle of replication in CD8+ lymphocytes and the remaining CD4+ cells, culminating in the death of all cells on day 39 postinoculation.

Soluble and membrane-associated interleukin 2 receptor-alpha expression in rhesus monkeys infected with simian immunodeficiency virus.

More than 80% of rhesus monkeys infected with simian immunodeficiency virus (SIV) were found to have elevated levels of soluble interleukin-2 receptor (IL-2R) in their serum during the course of infection. All long-term survivors had stably elevated levels of soluble IL-2R. The highest levels of soluble IL-2R correlated with the expression of IL-2R on tissue macrophages. Although IL-2R expression was induced on alveolar macrophages by infection with SIV in vitro, expression of IL-2R on tissue macrophages in vivo was not associated with concurrent SIV protein expression in the same cells. Moreover, in animals with high soluble IL-2R levels, there was an inverse relationship between the numbers of cells expressing IL-2R and cells expressing viral protein. The results suggest that the induction of IL-2R may be an indirect or secondary effect of SIV infection. Changes in expression of macrophage-elaborated factors, such as that of IL-2R described in this report, may play a crucial role in some of the pathologic features of acquired immunodeficiency syndrome.

The productive infection of alveolar macrophages by simian immunodeficiency virus.

Alveolar macrophages obtained from healthy rhesus monkeys were infected with SIV in vitro as documented by the appearance of reverse transcriptase activity in the cell-free supernatant, electronmicroscopy, and immunohistochemical methods detecting SIV-related core protein. The results demonstrate permissive infection of alveolar macrophages with SIV in vitro and define a system for studying macrophage-SIV interactions.

CD8+CD4- lymphocyte lines can harbor the AIDS virus in vitro.

A detailed definition of AIDS virus-specific T lymphocytes will require the generation and characterization of HIV-1-specific, cloned T cell populations. In our studies, we show that CD8+CD4- lymphocyte lines, derived from PBL of rhesus monkeys infected with simian immunodeficiency virus of macaques and humans infected with HIV-1, can harbor AIDS viruses. CD8+CD4- lymphocyte lines derived from infected individuals are shown to express AIDS virus-encoded proteins and generate reverse transcriptase activity. Infection of these CD8+CD4- lymphocytes is confirmed at the single cell level by the techniques of immunoelectronmicroscopy and two-color immunohistochemistry. This observation suggests that it may prove problematic to generate cloned, functional T lymphocyte populations from AIDS virus-infected individuals and raises the possibility that CD8+CD4- cells may serve as reservoirs for the AIDS viruses.