Facilitating the gut brain axis by probiotic bacteria to modulate neuroimmune response on lead exposed zebra fish models

Unravelling the efficacy of gut biome has a major impact on health. An unbalanced microbiome composition is linked to many common illnesses such as gut dysbiosis, mental deformities and immunological imbalance. An optimistic influence on the gut biome can be made by consumingprobiotics. This would stimulate neuroprotection and immunomodulation intended by heavy metals pollution. Lead is a major source of neurotoxin that can induce neural deformities. Lactobacillusspecies isolated from curd were characterized to confirm its specificity. Zebra fish was reared at standard conditions and preclinical assessment on the intensity of induced neurotoxin lead was performed. The embryo toxic assay, immunomodulation effects and animal behavioural models endorsed the consequence of neurotoxicity. Different concentrations of bacterial isolate with standard antidepressant was considered for analysing the vigour of toxicity and its influence on cognitive behaviour by novel tank diving method. The restrain in the animal behaviour was also conferred by all the test samples with a decreased bottom dwelling time which was authenticated with haematology and histopathological studies. The alterations in morphology of the lymphocytes were balanced by the treated test samples. This study paves a twofold potential of probiotic as neuroprotectant and immune modulator against heavy metal toxicity.

The role of myeloid-derived suppressor cells in chronic infectious diseases and the current methodology available for their study.

An effective pathogen has the ability to evade the immune response. The strategies used to achieve this may be based on the direct action of virulence factors or on the induction of host factors. Myeloid-derived suppressor cells (MDSCs) are immune cells with an incredible ability to suppress the inflammatory response, which makes them excellent targets to be exploited by pathogenic bacteria, viruses, or parasites. In this review, we describe the origin and suppressive mechanisms of MDSCs, as well as their role in chronic bacterial, viral, and parasitic infections, where their expansion seems to be essential in the chronicity of the disease. We also analyze the disadvantages of current MDSC depletion strategies and the different in vitro generation methods, which can be useful tools for the deeper study of these cells in the context of microbial infections.

Clinical features, fungal load, coinfections, histological skin changes, and itraconazole treatment response of cats with sporotrichosis caused by Sporothrix brasiliensis.

Zoonotic sporotrichosis caused by the fungus Sporothrix brasiliensis is usually severe in cats. This study investigated the associations between clinical features, fungal load, coinfections, histological skin changes, and response to itraconazole in cats with sporotrichosis caused by S. brasiliensis. Fifty-two cats with skin lesions and a definitive diagnosis of sporotrichosis were treated with itraconazole for a maximum period of 36 weeks. The animals were submitted to clinical examination and two subsequent collections of samples from the same skin lesion for fungal diagnosis and histopathology, as well as serology for feline immunodeficiency (FIV) and leukaemia (FeLV) viruses. Thirty-seven (71%) cats were clinically cured. Nasal mucosa lesions and respiratory signs were associated with treatment failure. Cats coinfected with FIV/FeLV (n = 12) had a lower neutrophil count in the lesion. A high fungal load in skin lesions was linked to young age and treatment failure, as well as to a longer time of wound healing, poorly formed granulomas and fewer neutrophils, macrophages and lymphocytes in these lesions. These results indicate that itraconazole is effective, but nasal mucosal involvement, respiratory signs and high fungal loads in skin lesions are predictors of treatment failure that will assist in the development of better treatment protocols for cats.

Livestock abundance predicts vampire bat demography, immune profiles and bacterial infection risk.

Human activities create novel food resources that can alter wildlife-pathogen interactions. If resources amplify or dampen, pathogen transmission probably depends on both host ecology and pathogen biology, but studies that measure responses to provisioning across both scales are rare. We tested these relationships with a 4-year study of 369 common vampire bats across 10 sites in Peru and Belize that differ in the abundance of livestock, an important anthropogenic food source. We quantified innate and adaptive immunity from bats and assessed infection with two common bacteria. We predicted that abundant livestock could reduce starvation and foraging effort, allowing for greater investments in immunity. Bats from high-livestock sites had higher microbicidal activity and proportions of neutrophils but lower immunoglobulin G and proportions of lymphocytes, suggesting more investment in innate relative to adaptive immunity and either greater chronic stress or pathogen exposure. This relationship was most pronounced in reproductive bats, which were also more common in high-livestock sites, suggesting feedbacks between demographic correlates of provisioning and immunity. Infection with both Bartonella and haemoplasmas were correlated with similar immune profiles, and both pathogens tended to be less prevalent in high-livestock sites, although effects were weaker for haemoplasmas. These differing responses to provisioning might therefore reflect distinct transmission processes. Predicting how provisioning alters host-pathogen interactions requires considering how both within-host processes and transmission modes respond to resource shifts.This article is part of the theme issue 'Anthropogenic resource subsidies and host-parasite dynamics in wildlife'.

Long-term cell culture isolated from lesions of mice infected with Leishmania amazonensis: a new approach to study mononuclear phagocyte subpopulations during the infection.

Leishmanioses are neglected diseases and the parasite Leishmania survives and proliferates within mononuclear phagocytes, particularly macrophages. In vitro studies of the immunology and cell biology of leishmaniosis are performed in murine peritoneum and bone marrow macrophages and immortalized cell lines despite the normal and injured tissue-specific heterogeneity of macrophages. In this work, we established an ex vivo methodology to culture lesional cells from BALB/c mice infected with Leishmania amazonensis. The cells were successfully isolated from footpad skin lesions and those exhibiting macrophage morphology were maintained in long-term culture (12 days), while the small number of lymphocytes, polymorphonuclear and unidentified cells died after 1 day of culture. The frequency of infected cells decreased over 2 days. Most lesional cells cultivated ex vivo were myeloid CD11b+ CD14+ F4/80+ CD68+ cells. Low levels of IFN-γ and IL-4, IL-10 production and low arginase and phagocytic activities were detected in ex vivo lesional cell cultures. The ex vivo model developed in this study open perspectives for studying the biology of leishmanial lesions in cellular subpopulations and at the single-cell level.

Caracterização fenotípica e funcional das células T CD4+ e CD8+ VB12 na resposta imune em paciente com Leishmaniose Cutânea Localizada / Phenotypic and functional characterization of CD4 + and CD8 + VB12 T cells in the immune response in a patient with Localized Cutaneous Leishmaniasis

As leishmanioses constituem um complexo de doenças causada pelo protozoário intracelular, do gênero Leishmania, sendo a resposta imune celular essencial para controle, eliminação e proteção contra a infecção. A teoria clonal da imunidade celular propõe que as respostas imunológicas são estabelecidas através do aumento na frequência de clones específicos ao antígeno. Para avaliar a resposta das células T à infecção por Leishmania, investigamos, por citometria de fluxo, a expressão de cadeias Vβ de receptores de células T (TCRs), estado de ativação, capacidade de adesão ao endotélio e potencial funcional de clones específico. Em um grupo de pacientes com Leishmaniose Cutânea Localizada (LCL), avaliamos diferentes subpopulações de células T através da expressão da região Vβ, no sangue periférico e na biópsia da lesão. Utilizamos células mononucleares de sangue periférico (CMSPs), de pacientes LCL e controles saudáveis, nas quais avaliamos, ex vivo, a expressão de moléculas de ativação (CD25, CD69 e HLA-DR), adesão (LFA-1, VLA-4 e CD62L), co-estimulatória (CD27 e CD28)...

Leishmaniasis is a desease caused by infection with the Leishmania protozoan parasite. The cellular immune response is essential for controlling, eliminating and protection of the Leishmania infection. The clonal theory of cellular immunity proposes that immunological responses are established by increasing the frequency of antigen-specific clones. In order to measure the host T cell response to Leishmania infection, we have investigated by flow cytometry, the expression of Vβ chains of T-cell receptors (TCRs), activation state, adhesion to endothelium of capacity and functional potential of specific T. In a group of localized cutaneous leishmaniasis (LCL) patients, we evaluated different T cell subpopulations as identified by their Vβ region expression, in peripheral blood and biopsy. We used peripheral blood mononuclear cells (PBMCs), from CL patients and healthy volunteers, in which we evaluate, ex vivo, the expression of activation molecules (CD25, CD69 and HLA-DR), adhesion (LFA-1, VLA-4 and CD62L), co-stimulatory (CD27 and CD28)...

Cross-reactivity of commercially available anti-human monoclonal antibodies with canine cytokines: establishment of a reliable panel to detect the functional profile of peripheral blood lymphocytes by intracytoplasmic staining.

BACKGROUND: The process for obtaining monoclonal antibodies against a specific antigen is very laborious, involves sophisticated technologies and it is not available in most research laboratories. Considering that most cytokines remain partially conserved among species during evolution, the search for antibody cross-reactivity is an important strategy for immunological studies in veterinary medicine. In this context, the amino acid sequence from human and canine cytokines have demonstrated 49-96 % homology, suggesting high probability of cross-reactivity amongst monoclonal antibodies. For this, 17 commercially available anti-human monoclonal antibodies [IL-1α, IL-1ß, IL-2, IL-4, IL-5, IL-6, IL-8 (#1, #2), IL-10, IL-12, IL-13, IL-17A, IFN-γ (#1, #2), TNF-α (#1, #2) and TGF-ß], were evaluated in vitro for intracellular cytokine detection in a stimulated canine blood culture by flow cytometry and confocal microscopy. Lymphocytes from peripheral blood of healthy and two unhealthy dogs were analyzed. RESULTS: Eleven anti-human mAbs [IL-1α, IL-4, IL-5, IL-6, IL-8 (#1, #2), IL-12, IL-17A, TNF-α (#1, #2) and TGF-ß] cross-reacted against canine intracellular cytokines. The specificity of the assays was not affected after Fc-blocking. Three anti-human cytokine mAbs [IL-4, IL-8 (#2) and TGF-ß] when evaluated by confocal microscopy also cross-reacted with intracellular canine cytokines. The identification of human mAbs that cross-reacted with canine cytokines may support their use as immunological biomarkers in veterinary medicine studies. CONCLUSION: The identification of these 11 anti-human cytokine mAbs that cross-reacted with canine cytokines will be useful immunological biomarkers for pathological conditions by flow cytometry and fluorescence microscopy in dogs.

Efecto in vitro de la Matricaria recutita L. sobre la respuesta de linfocitos y neutrófilos / In vitro effect of Matricaria recutita L. on Lymphocytes and Neutrophils response

La manzanilla de Castilla, dulce o cimarrona (Matricaria recutita o Matricaria chamomilla), es una planta herbácea anual de la familia de las asteráceas, nativa de Europa y de regiones templadas de Asia, que se ha naturalizado en algunas regiones de América, África y Australia. Ha sido utilizada por el hombre desde hace miles de años con diferentes fines medicinales. Se estudió el efecto in vitro de un extracto fluido de esta planta sobre los linfocitos de 20 donantes voluntarios de sangre y de 20 enfermos con diagnóstico de inmunodeficiencia celular, mediante la cuantificación de los linfocitos T por las técnicas de formación de roseta espontánea y activa y el ultramicrométodo inmunocitoquímico (UMICIQ), así como la función fagocítica (índice opsonofagocítico) de los neutrófilos. No se hallaron diferencias estadísticamente significativas en los parámetros estudiados entre las condiciones experimentales con Matricaria y sin esta

Castilla Chamomile, sweet, or maroon (Matricaria recutita or Matricaria chamomilla) is an annual herbaceous plant of the Asteraceae family, native to Europe and temperate zones of Asia, which has become naturalized in parts of America, Africa, and Australia. It has been used by man for thousands of years with different medicinal purposes. We studied the in vitro effect of an extract fluid of this plant on lymphocytes from 20 blood donors and 20 patients with a diagnosis of cellular immunodeficiency. We quantified T lymphocytes by the techniques of spontaneous and active rosette formation, and the immunocytochemical ultramicromethod (UMICIQ) as well as the phagocytic function (opsonophagocytic index) of neutrophils. There were no statistically significant differences in the studied parameters between experimental conditions with Matricaria and without it

Treatment of rats with heat killed cells (HKC) of Cryptococcus neoformans var. grubii induces cellular activation in spleen and lymphatic nodes.

Our previous studies showed that the subcutaneous pretreatment of rats with heat killed cells of Cryptococcus neoformans (HKC) emulsified in complete Freund adjuvant (CFA) promotes protection against an intraperitoneal challenge with viable C. neoformans. In this model, an appropriate activation of adherent peritoneal cells after antigenic treatment is very important for the control of the infection. Here, we investigated the immune response developed in spleen and lymphatic nodes as a result of treatment with HKC-CFA, which might also contribute in the protective phenomenon of this treatment against cryptococcal infection. The results show that, compared with adjuvant alone, rats which received treatment with HKC-CFA presented a greater activation of adherent splenic cells, with up-regulation of major histocompatibility complex class II (MHC II) and CD86 expression and secretion of anticryptococcal metabolites. Furthermore, this treatment also induced an increase in the blastogenic response and the secretion of Th1 and Th2 cytokines by spleen cells in comparison with cells from CFA-phosphate-buffered saline (PBS) treated rats. On the other hand, lymph node cells from animals treated with HKC-CFA presented a rise in the expression of MHCII but not of CD86 with respect to control cells from rats treated with CFA-PBS. These cells also showed a high proliferative response and secretion of Th1-related cytokines, interleukin (IL)-12 and tumor necrosis factor (TNF). These results show that treatment of rats with HKC-CFA is able to induce an early immune response in secondary lymphoid organs, which may contribute to the protective effect induced by this treatment.

SopB effector protein of Salmonella Typhimurium is translocated in mesenteric lymph nodes during murine salmonellosis.

Salmonella Typhimurium harbors two Salmonella pathogenicity islands (SPIs), each encoding a type three secretion system for virulence proteins. Although there is increasing evidence of postinvasion roles for SPI-1, it has been generally accepted that SPI-1 genes are downregulated following the invasion process. Here, we analyzed the expression and translocation of SopB in vitro, in cell culture and in vivo. To this end, a sopB-FLAG-tagged strain of Salmonella Typhimurium was obtained by epitope tagging. Tagged proteins were detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunoblotting with anti-FLAG antibodies. SopB expression was observed in vitro under cultured conditions that mimic the intestinal niche and different intracellular environments. In agreement, bacteria isolated from infected monolayers expressed and translocated SopB for at least 24 h postinoculation. For in vivo experiments, BALB/c mice were inoculated intraperitoneally with the tagged strain of Salmonella Typhimurium. Infecting bacteria and infected cells were recovered from mesenteric lymph nodes. Our results showed that SopB continues to be synthesized in vivo during 5 days after inoculation. Interestingly, translocation of SopB was detected in the cytosol of cells isolated from lymph nodes 1 day after infection. Altogether, these findings indicate that the expression and translocation of SopB during Salmonella infection is not constrained to the initial host-bacteria encounter in the intestinal environment as defined previously.

Flaxseed, olive and fish oil influence plasmatic lipids, lymphocyte migration and morphometry of the intestinal of Wistar rats / Óleo de linhaça, oliva e peixe influenciam os lipídios plasmáticos, migração de linfócitos e morfometria intestinal de ratos Wistar

PURPOSE: Evaluate the effect of flaxseed, olive and fish oil on the lipid profile, preservation of villosities and lymphocyte migration in the intestinal mucosa of Wistar rats. METHODS: Thirty Wistar male rats were divided into four groups, which received the AIN-93M diet, with changes only to their lipid source: flaxseed, olive, fish, and soy oil (control group). The serum was separated for the biochemical parameter analysis. A histological evaluation was performed in the ileal portion. RESULTS: The group which was fed fish oil presented lower values when compared to the other treatments for Total Cholesterol, High-density Lipoprotein Cholesterol and Triacylglycerol (p<0.05). The animals treated with fish and olive oils presented better intestinal villosities preservation. Less deposition of lymphocytes was observed in the flaxseed group (p<0.001). CONCLUSIONS: This study demonstrated that flaxseed, olive and fish oils present different responses than soy oil for the intestinal mucosa preservation and lymphocyte proliferation in Wistar rats.(AU)

OBJETIVO: Avaliar o efeito dos óleos de linhaça, oliva e peixe no perfil lipídico, preservação das vilosidades e migração de linfócitos na mucosa intestinal de ratos Wistar. MÉTODOS: Trinta ratos Wistar foram divididos em quarto grupos e receberam dieta AIN-93M, modificando para cada grupo apenas a fonte lipídica: óleo de linhaça, oliva, peixe e soja ( grupo controle). O soro foi separado para análise dos parâmetros bioquímicos. A análise histológica foi realizada na porção ileal. RESULTADOS: O grupo que recebeu óleo de peixe apresentou menores valores de colesterol total, lipoproteína de alta densidade e triacilglicerol (p<0.05). Os animais tratados com óleo de peixe e oliva apresentaram melhor preservação das vilosidades intestinais. Menor deposição de linfócitos foi observado no grupo tratado com óleo de linhaça (p<0.001). CONCLUSÃO: Este estudo demonstrou que os óleos de linhaça, oliva e peixe apresentam diferentes respostas em relação ao óleo de soja na preservação da mucosa intestinal e proliferação de linfócitos em ratos Wistar.(AU)

Abnormal production of transforming growth factor beta and interferon gamma by peripheral blood cells of patients with multidrug-resistant pulmonary tuberculosis in Brazil.

OBJECTIVES: The aim of the present study was to determine the immune response profile that differentiates patients with newly diagnosed (non-treated) pulmonary tuberculosis from multidrug-resistant (MDR) ones, as well as from healthy, tuberculin positive individuals. METHODS: Lymphocytes proliferative response to non-specific mitogen (PHA) and PPD were evaluated by 3H thymidine incorporation and cytokines were quantified using an ELISA assay. RESULTS: Patients with active disease showed a diminished proliferative response to PHA and PPD, while multidrug-resistant patients showed a diminished proliferative response to PHA, but a normal response to PPD. The cytokine production of newly diagnosed patients was characterized by a diminished production of IFNgamma and normal production of transforming growth factor (TGFbeta), while MDR patients revealed a normal production of IFNgamma accompanied by an increase in TGFbeta. CONCLUSIONS: The production of significant amounts of TGFbeta in MDR patients leads to a poor immune response and may contribute to the resistance of tuberculosis patients to drugs.

[Connective tissue degradation in human amniochorion after stimulation with choriodecidual lymphocytes infected with group B streptococci]. / La interacción de las células inmunológicas coriodeciduales con estreptococo del grupo B condiciona la degradación del tejido conectivo del corioamnios.

OBJECTIVE: To identify whether soluble products from choriodecidual blood cells stimulated with group B streptococci (GBS) induce connective tissue degradation in human amniochorion. MATERIAL AND METHODS: Blood samples from choriodecidual compartment were collected by direct aspiration from placental cotyledons draining blood and represent local circulating cells. Samples were divided into two aliquots: one was stimulated with GBS (1 X 10(6) CFU/mL) and the other was kept free of bacteria as negative control. After overnight incubation, plasmas were separated. Chorioamnion explants were stimulated with 10% plasma for 12h at 37 degrees C in 5% CO2. MMP-9 proteolytic activity was measured in the supernatants by gelatin-zymography and IL-1beta and TNF-alpha were quantified by ELISA. Distribution of the collagenous fibrils in explants was examined by electron microscopy. STATISTICAL ANALYSIS: three independent experiments on duplicate were carried out and the statistical significance of experimental differences between groups was assessed with ANOVA test. RESULTS: MMP-9, IL-1beta and TNF-alpha production was significantly higher in supernatants from explants co-cultured with choriodecidual plasma from blood previously infected with GBS, compared with control plasma. Accompanying extensive changes of connective tissue arrangement confirm induction of extracellular matrix degradation. CONCLUSIONS: Choriodecidual plasma from blood stimulated with GBS is enriched with biochemical signals that enhance the MMP-9, IL-1alpha and TNF-beta production by amniochorion. These findings suggest that local circulating cells are capable to act in response to GBS choriodecidual infection through extracellular matrix degradation and the consequent rupture of membranes.

Activation of signaling lymphocytic activation molecule triggers a signaling cascade that enhances Th1 responses in human intracellular infection

T cell production of IFN-gamma contributes to host defense against infections by intracellular pathogens, including mycobacteria. Lepromatous leprosy, the dissminated from of infection caused by Mycobacterium leprae, is characterized by loss of cellular response against the pathogen and diminished Th1 cytokine production. Relieving bacterial burden in Ag-unresponsive patients might be achieved through alternative receptors that stimulate IFN-gamma production. We have previously shown that ligation of signaling lymphocytic activation molecule (SLAM) enhances IFN-gamma in mycobacterial infection; therefore, we investigated molecular pathways leading from SLAM activation to IFN-gamma production in human leprosy. The expression of the SLAM-associated protein (an inhibitory factor for IFN-gamma induction) on M. leprae-stimulated cells from leprosy patients was inversely correlated to IFN-gamma production. Howevwe, SLAM ligation or exposure of cell from lepromatous patients to a proinflammatory microenvironment down-regulated SLAM-associated protein expression. Moreover. SALAM activation induced a sequence of signaling proteins, including activation of the NF-kB complex, phosphorylation of Stat1, and induction of T-bet expression, resulting in the promotion a cascade of molecular events during signaling through SLAM in leprosy that cooperate to induce INF-gamma production and strongly suggest that SLAM might be a focal point for therapeutic modulation of the cell cytokine responses in diseases characterized by dysfunctional Th2 responses

Clastogenic effects of different Ureaplasma urealyticum serovars on human chromosomes.

The possibility that Ureaplasma urealyticum might play an important role in human infertility was first raised more than 20 years ago, but this association remains speculative. Considering the hypothesis that the pathogenicity of Ureaplasma urealyticum may depend on its serotypes, the clastogenic effects of different strains of Ureaplasma urealyticum, at concentrations of 10(3) CCU (color changing units)/ml, 10(4) CCU/ml and 10(5) CCU/ml, were evaluated in vitro in short-term cultures of human lymphocytes. Total or partial mitotic inhibition was produced by Ureaplasma urealyticum serotypes 2, 3 and 10 independent of the concentration (10(3) CCU/ml, 10(4) CCU/ml or 10(5) CCU/ml) of the microorganisms employed. In contrast, the clastogenic effects observed with serotypes 1, 7 and 12 varied according to the concentration employed in the test. Mitotic alterations were observed in Ureaplasma urealyticum serotypes 5, 6, 7, 8, 9, 11 and 12. Chromatid gaps (53.0%) and chromatid breaks (13.9%) were the most frequent types of alterations observed. The results of this in vitro assay demonstrated that the clastogenic effects varied with the Ureaplasma urealyticum serotypes evaluated.

Clastogenic effects of different Ureaplasma urealyticum serovars on human chromosomes

The possibility that Ureaplasma urealyticum might play an important role in human infertility was first raised more than 20 years ago, but this association remains speculative. Considering the hypothesis that the pathogenicity of Ureaplasma urealyticum may depend on its serotypes, the clastogenic effcts of different strains of Ureaplasma urealyticum, at concentrations of 10(3) CCU (color changing units)/ml, 10(4) CCU/ml and 10(5) CCU/ml, were evaluated in vitro in short-term cultures of human lyphocytes. Total or partial mitotic inhibition was produced by Ureaplasma urealyticum serotypes 2,3 and 10 independent of the concentration (10(3) CCU/ml, 10(4) CCU/ml or 10 (5) CCU/ml) of the microorganisms employed. In contrast, the clastogenic effects observed with serotypes 1,7 and 12 varied according to the concentration employed in the test. Mitotic alterations were observed in Ureaplasma urealyticum serotypes 5,6,7,8,9,11 and 12. Chromatid gaps (53.0 percent) and chromatid breaks (13.9 percent) were the most frequent types of alterations observed. The results of this in vitro assay demonstrated that the clastogenic effects varied with the Ureaplasma urealyticum serotypes evaluated.

Support of Paracoccidioides brasiliensis multiplication by human monocytes or macrophages: inhibition by activated phagocytes.

The interaction of human monocytes or monocyte-derived macrophages and yeast-form Paracoccidioides brasiliensis was studied in vitro. Yeast cells were readily ingested by adherent monocytes or macrophages. Multiplication of P. brasiliensis, measured by growth as colony forming units (cfu) on a supplemented medium with good plating efficiency, was greater in monocyte co-cultures compared to the number of cfu obtained from complete tissue-culture medium (CTCM). Multiplication increased with time in macrophage co-cultures, e.g., from two-six-fold in 24 h to nine-fold in 72 h. Microscopic observations indicated that ingested yeast cells multiplied inside macrophages. When monocytes were treated with supernate cytokines (CK) from concanavalin-A-stimulated mononuclear cells, then co-cultured with P. brasiliensis, multiplication was significantly inhibited compared with control monocyte co-cultures. Treatment of macrophages--derived from monocytes by culture in vitro for 3 days--for a further 3 days with CK resulted in maximal inhibition of multiplication over the subsequent 72 h. Similarly, when monocyte-derived macrophages (after culture for 7 days) were treated for 3 days with recombinant human gamma-interferon (IFN; 300 U/ml) or CK they restricted multiplication of P. brasiliensis by 65% and 95%, respectively, compared with control macrophages. Antibody to IFN abrogated the effect of IFN or CK treatment. These findings show that ingested P. brasiliensis can multiply in human monocytes or macrophages and that this multiplication can be restricted by activated monocytes or macrophages.

High rate of infection with the human T-cell leukemia retrovirus type II in four Indian populations of Argentina.

Sera from 215 non-drug-injecting Toba and Mataco-Mataguayo pure Indians belonging to four communities in northern Argentina were examined using assays that allow differentiation between reactivities due to type-specific antigens of the human T-cell leukemia/lymphoma virus (HTLV). Three of these populations have very little contact with non-Indian groups and reside in remote, isolated areas. HTLV-II type-specific seroreactivity was present in 24 (13.7%) of the 175 Indians older than 13 years of age and in none of the 40 who were of younger ages. None of the Indians had antibodies reacting with HTLV-I type-specific antigen. Seroreactivity was more prevalent and appeared at younger ages in females than in males. The majority of the HTLV-II-seropositive Indians belonged to the more isolated communities. The seroprevalences among the Tobas and Mataco-Mataguayo Indians were comparable. With the exception of a Toba who was positive in a test for Treponema pallidum, no serological evidence of sexually transmitted infections with this spirochete, hepatitis B virus, hepatitis C virus, and human immunodeficiency virus was found among the Indians tested. None of the 55 non-Indian people tested in the region showed HTLV-II type-specific seroreactivity. PCR analysis of DNA isolated from peripheral blood lymphocytes of seropositive Indians confirmed that the virus present in these populations is HTLV-II. Sequence analysis of PCR-amplified genomic segments showed that the virus belongs to the HTLV-II subtype which has been found to be endemic in other Paleo-American Indians.