RESUMEN
The human immunodeficiency virus type 1 (HIV-1), the etiological agent of the acquired immunodeficiency syndrome (AIDS), shows a variety of biological properties, which may constitute an obstacle to development of effective vaccines or antiretroviral therapy. To characterize Brazilian strains of HIV-1, we studied 24 viruses isolated from blood samples of HIV-1-positive patients from different regions of the country. To examine the cell tropism and the virus ability to form syncytia, primary macrophages and the CD4+ T cell line MT-2 were infected with these viruses. We found that 22 isolates replicated well in macrophages (macrophage-tropic isolates), 2 infected only MT-2 cells (T cell line tropic variants), while 6 of them grew in both cells. We found 8 syncytium-inducing (SI) and 16 non-SI (NSI) isolates. Continuous cultures of 18 isolates were established in the CCR5+/CXCR4+ cell line PM-1, and SI/NSI features of these viruses were confirmed by cell fusion assay with uninfected CD4+ T cell lines (PM-1, MT-2, H9, and SUP-T1). The coreceptor usage of 18 isolates was investigated by infecting U87 cells transfected with CD4 and chemokine receptors, and we found that 11 isolates infected only CCR5+ cells, 3 only CXCR4+ cells, whereas 4 used both coreceptors. We also observed that X4 isolates were more sensitive to neutralization by dextran sulfate than R5 or R5X4 viruses. Our findings show that the Brazilian isolates are phenotypically similar to those prevalent in other regions, which could mean that therapeutic strategies based on HIV-1 phenotypic properties would be efficient in Brazil, as in other countries.
Asunto(s)
Infecciones por VIH/virología , VIH-1/aislamiento & purificación , VIH-1/metabolismo , Receptores CCR5/metabolismo , Receptores CXCR4/metabolismo , Brasil/epidemiología , Línea Celular , Sulfato de Dextran/farmacología , Células Gigantes/efectos de los fármacos , Células Gigantes/metabolismo , Células Gigantes/virología , Infecciones por VIH/epidemiología , VIH-1/efectos de los fármacos , VIH-1/genética , Humanos , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Macrófagos/virología , Especificidad por SustratoRESUMEN
In this study, we show the leishmanicidal effects of a chloroform fraction (CLF) and a purified indole alkaloid obtained from crude stem extract of Peschiera australis against Leishmania amazonensis, a causative agent of cutaneous leishmaniasis in the New World. In a bioassay-guided chemical fractionation, the leishmanicidal activity in CLF completely and irreversibly inhibited promastigote growth. This fraction was also active against amastigotes in infected murine macrophages. Chemical analysis of CLF identified an iboga-type indole alkaloid coronaridine as one of its major compounds. Coronaridine showed potent antileishmanial activity, inhibiting promastigote and amastigote growth. Promastigotes and amastigotes treated with CLF or coronaridine showed pronounced alterations in their mitochondria as assessed by transmission electron microscopy.
Asunto(s)
Alcaloides/farmacología , Antiprotozoarios/farmacología , Indoles/farmacología , Leishmania/efectos de los fármacos , Magnoliopsida/química , Animales , Ibogaína/análogos & derivados , Leishmania/ultraestructura , Macrófagos Peritoneales/efectos de los fármacos , Macrófagos Peritoneales/metabolismo , Macrófagos Peritoneales/ultraestructura , Ratones , Óxido Nítrico/metabolismo , Extractos Vegetales/químicaRESUMEN
The Brazilian Network for HIV Isolation and Characterization was established for the surveillance of HIV variability in Brazil. Here, we report characterization of HIV strains and virus-specific immune responses from 35 clinical samples collected from three potential HIV vaccine sites. Three genetic subtypes of HIV-1 were identified by heteroduplex mobility assay (HMA) B (in 82.9% of the samples), F (14.3%), and C (2.9%). Phylogenetic analysis based on the C2V3/env DNA sequence from all 25 specimens examined was 100% concordant with HMA results. Four variants of subtype B with different tetrapeptides at the tip of the V3 loop were found: the GPGR motif (North American), GWGR motif (Brazilian B"), and two minor variants, GFGR and GPGS, as previously detected. No significant association was found between HIV-1 subtypes and the mode of transmission or biologic properties of HIV-1 isolates (derived from 88.6% of the specimens). Only 5 of 16 isolates studied were neutralized by the autologous sera. Consistent with previous results, no relation between viral subtype and peptide enzyme-linked immunosorbent assay (ELISA) seroreactivity or neutralization was evident. This study also demonstrated the effectiveness of the collaborative approach followed by Brazilian scientists when addressing a complex subject such as HIV variability.
Asunto(s)
Vacunas contra el SIDA , Infecciones por VIH/epidemiología , VIH-1/clasificación , Adolescente , Adulto , Secuencia de Aminoácidos , Brasil/epidemiología , Femenino , Proteína gp120 de Envoltorio del VIH/análisis , Infecciones por VIH/virología , VIH-1/genética , VIH-1/inmunología , Humanos , Masculino , Persona de Mediana Edad , Datos de Secuencia Molecular , Fragmentos de Péptidos/análisis , Filogenia , Factores de Riesgo , Análisis de SecuenciaRESUMEN
In this paper we relate that sera from paracoccidioidomycosis patients inhibited the mitogen-induced proliferative responses of normal mononuclear cells. Treatment of these sera with 2.5% polyethyleneglycol (PEG), a method classically used to precipitate immune complexes, significantly reduced their inhibitory activity. Immunoblot analysis of the PEG precipitates identified a 34-kDa polypeptide, recognized by rabbit anti-P. brasiliensis IgG. Patient mononuclear cells showed partial restoration of their proliferative capacity after 24 h culture in medium alone, which suggests release of membrane-bound molecules in the culture medium. These findings indicate that circulating P. brasiliensis antigens, complexed or not with antibodies, may play a negative immunoregulatory effect in the mitogen-induced proliferative responses of paracoccidioidomycosis patients.
Asunto(s)
Anticuerpos Antifúngicos/sangre , Anticuerpos Antifúngicos/fisiología , Sueros Inmunes/fisiología , Inmunosupresores/farmacología , Leucocitos Mononucleares/inmunología , Activación de Linfocitos , Paracoccidioidomicosis/sangre , Paracoccidioidomicosis/inmunología , Animales , Complejo Antígeno-Anticuerpo/sangre , Complejo Antígeno-Anticuerpo/fisiología , Células Cultivadas , Humanos , Leucocitos Mononucleares/efectos de los fármacos , Activación de Linfocitos/efectos de los fármacos , Peso Molecular , Polietilenglicoles/farmacología , ConejosRESUMEN
Dopamine pharmacokinetics was investigated in 14 critically ill newborn infants ranging from 27 to 43 weeks of gestational age and from 0.9 to greater than 4 kg birth weight. Plasma clearance rate was determined from dopamine levels during controlled infusions under actual clinical conditions. Dopamine was administered in stepwise increasing doses up to 8 micrograms/kg/min. Dopamine concentration and dopamine clearance rate were determined from duplicate samples drawn during each infusion in each patient. Steady-state plasma dopamine concentrations and plasma clearance rates were observed within 20 minutes at each infusion. Plasma dopamine concentration ranged from 0.5 ng/ml before infusion to almost 70 ng/ml at an infusion rate of 4 to 8 micrograms/kg/min. There was a linear correlation between infusion rate and plasma dopamine concentration (r = 0.68, p less than 0.001). Neither plasma dopamine concentration nor infusion rate had a significant effect on clearance rate. These data are consistent with first-order kinetics for administered dopamine in critically ill neonates over the range of concentrations studied.
Asunto(s)
Dopamina/farmacocinética , Enfermedades del Recién Nacido/metabolismo , Peso al Nacer , Cuidados Críticos , Dopamina/administración & dosificación , Dopamina/sangre , Edad Gestacional , Humanos , Recién Nacido , Infusiones Intravenosas , Tasa de Depuración MetabólicaRESUMEN
Paracoccidioidomycosis (PCM) is often associated with hypergammaglobulinemia and increased serum levels of circulating immune complexes (CIC). In order to investigate whether polyclonal B lymphocyte activation (PBA) is a current process in PCM, we measured the numbers of IgG secreting cells (IgG SC) in the peripheral blood of 16 patients and of 8 healthy controls. The numbers of IgG SC were found to be significantly elevated in PCM patients. We also observed increased serum levels of IgG, IgA and CIC. These data reflect an activation of B lymphocytes in PCM patients.
Asunto(s)
Linfocitos B/inmunología , Inmunoglobulina G/inmunología , Activación de Linfocitos , Paracoccidioidomicosis/inmunología , HumanosRESUMEN
1. The nature and extent of immune abnormalities was studied in 28 untreated patients with a chronic moderate form of paracoccidioidomycosis (PCM). 2. The patients presented hyporeactivity to skin tests, diminished lymphocyte transformation by mitogens such as phytohemagglutinin-P and concanavalin A and by Paracoccidioides brasiliensis protein antigen. They also presented peripheral blood leukocytosis but normal absolute numbers of T-cell and T-cell subsets. 3. The patients had increased serum levels of C3d, as well as high levels of circulating immune complexes (CIC) detected by C1q-binding and protein A-binding assays. 4. There was a significant negative correlation between lymphocyte transformation by mitogens and CIC levels which suggested that CIC may be involved in the genesis of the depressed cell-mediated immunity in PCM patients.
Asunto(s)
Complejo Antígeno-Anticuerpo/análisis , Síndromes de Inmunodeficiencia/inmunología , Paracoccidioidomicosis/inmunología , Complemento C3d/análisis , Humanos , Inmunidad Celular , Activación de Linfocitos , Pruebas Cutáneas , Linfocitos T/inmunologíaRESUMEN
1. The nature and extent of immune abnormalities was studied in 28 untreated patients with a chronic moderate form of paracoccidioidomycosis (PCM). 2. The patients presented hyporeactivity to skin tests, diminished lymphocyte transformation by mitogens such as phytohamgglutinin-P and concanavalin A and by Paracoccidioides brasiliensis protein antigen. They also presented peripheral blood leukocytosis but normal absolute numbers of T-cell and T-cell subsets. 3. The patients had increased serum levels of C3d, as well as high levels of circulating immune complexes (CIC) detected by C1q-binding and protein A-binding assays. 4. There was a significant negarive correlation between lymphocyte transformation by mitogens and CIC levels which suggested that CIC may be involved in the genesis of the depressed cell-mediated immunity in PCM patients
Asunto(s)
Humanos , Complejo Antígeno-Anticuerpo/análisis , Síndromes de Inmunodeficiencia/inmunología , Paracoccidioidomicosis/inmunología , Complemento C3d/análisis , Inmunidad Celular , Activación de Linfocitos , Pruebas Cutáneas , Linfocitos T/inmunologíaRESUMEN
A monoclonal antibody (MAb), designated H3, with specificity for hamster lymphocytes, was produced by somatic cell hybridization of myeloma Sp 2/0 and spleen cells of Balb/c mice immunized with suspensions of viable hamster thymocytes. The H3 MAb (IgG 3) reacted specifically with hamster thymocyte surface membranes (immunofluorescent assay). The antibody recognized a protein of an approximate molecular weight of 44,000 Daltons in immunoblots of hamster thymocyte extracts. The soluble H3 MAb presented potent mitogenic properties as indicated by the DNA synthesis induced in in vitro hamster lymphocyte cultures.
Asunto(s)
Anticuerpos Monoclonales/biosíntesis , Mitógenos , Linfocitos T/inmunología , Timo/inmunología , Animales , Anticuerpos Monoclonales/inmunología , Especificidad de Anticuerpos , Cricetinae , Electroforesis en Gel de Poliacrilamida , Epítopos/inmunología , Técnica del Anticuerpo Fluorescente , Mesocricetus , Peso MolecularRESUMEN
A retrovirus infecting a Brazilian AIDS patient was isolated and characterized in terms of its reactivity with sera from individuals infected with human immunodeficiency viruses 1 and 2 (HIV-1 and HIV-2). The Western blot analysis revealed that the Brazilian isolate is very similar to the well characterized HIV-1 strain. The serum of the patient from whom the virus was isolated did not react with the 140 kDa envelope glycoprotein specific for HIV-2.