RESUMO
A 72 kDa Trypanosoma cruzi glycoprotein recognized by the 164C11 monoclonal antibody (IgM isotype) was purified by preparative electrophoresis. The antigenic preparation obtained, named TcY 72, was used to immunize C57Bl/10 mice. The following results were observed after immunization: (1) induction of higher titres of IgG than IgM antibodies, as evaluated by indirect immunofluorescence; (2) significant DTH after injection of epimastigotes in mice footpads; (3) peak parasitemia in immunized mice was significantly reduced and animals were negative by 13 days post-infection, although the mice still succumb to infection; (4) the phenotypic analysis of spleen cell populations showed a decrease in the CD4/CD8 ratio in immunized mice. Taken as a whole, these findings indicate that TcY 72 is immunogenic and potentially important for protective immunity.
Assuntos
Antígenos de Protozoários/imunologia , Doença de Chagas/imunologia , Glicoproteínas , Imunização , Trypanosoma cruzi/imunologia , Animais , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Fatores de TempoRESUMO
Monoclonal antibodies (mAbs) of the IgM isotypes were produced from mice immunized with blood forms of Trypansoma cruzi Y strain. Characterization of the epitope recognized by one of the mAbs, 164C11, as well as the effects of this mAb on complement-mediated lysis and host cell invasion are reported. Immunocytochemical analysis showed that the mAb was reactive with various strains of T. cruzi (Y, WSL, and Colombiana) as well as other trypanosomatids. The mAb 164C11 demonstrated a high complement-mediated lytic activity against bloodstream trypomastigotes, being more effective than chronic mouse serum. A protein with an apparent molecular weight of 72 kDa was detected by this mAb on all developmental stages of T. cruzi. Studies using periodate and endoglycosidase treatments suggested that the epitope is not a carbohydrate and seems to be located on the parasite membrane. In addition, preliminary results are presented, suggesting that the 72-kDa protein is involved in adhesion/or internalization of bloodstream trypomastigotes.
Assuntos
Anticorpos Monoclonais/biossíntese , Trypanosoma cruzi/imunologia , Animais , Anticorpos Monoclonais/farmacologia , Células Cultivadas , Ativação do Complemento , Epitopos/imunologia , Interações Hospedeiro-Parasita , Hibridomas/imunologia , Técnicas In Vitro , Camundongos , Trypanosoma cruzi/fisiologiaRESUMO
In a complete study in 25 patients with American cutaneous leishmaniasis, caused by Leishmania braziliensis complex, immunotherapeutic efficacy of parasite derived antigen (94-67 KD) has been compared to antimonial therapy. Additionally, to delineate the mechanism of therapeutic success, microscopical features of immune response in active lesions and healed or non-healed lesions following therapy were analyzed. The results showed that cure rates in immunotherapy and chemotherapy were equal (> 83%). The immunohistochemical changes in two therapeutic groups were also largely similar. The analysis of humoral and cellular immune response suggest that appropriate stimulation of T helper cells in the lesion site, in association with one or more cytokines, play a key role in the healing process.
Assuntos
Antígenos de Protozoários/uso terapêutico , Imunoterapia , Leishmania braziliensis/imunologia , Leishmaniose Cutânea/terapia , Adolescente , Adulto , Animais , Antígenos de Bactérias , Antígenos de Protozoários/imunologia , Brasil , Criança , Pré-Escolar , Feminino , Humanos , Leishmaniose Cutânea/imunologia , Macrófagos/imunologia , Masculino , Pessoa de Meia-Idade , Linfócitos T/imunologiaRESUMO
A simple rapid method of enzyme labeled anti-isotype assay (ELIA) for detection of monoclonal isotype on hybridoma cells is proposed. This alternative method was first carried out on hybridoma cell lines 147C11 and 257C11 produced against Trypanosoma cruzi and male accessory secretion of Panstrongylus megistus, respectively. The monoclonal antibodies produced by these hybridoma were characterized by this method as IgM (147C11) and IgG1 (257C23) isotypes, allowing evaluation of isotype without having to wait until the concentration of antibody present in the supernatant itself rises. Results were confirmed by Ouchterlony immunodiffusion. The proposed method offers the advantages of a permanent rapid procedure for light microscopy.
Assuntos
Anticorpos Monoclonais/classificação , Anticorpos Monoclonais/isolamento & purificação , Técnicas Imunoenzimáticas , Isotipos de Imunoglobulinas/isolamento & purificação , Animais , Biotecnologia , Estudos de Avaliação como Assunto , Hibridomas/imunologia , CamundongosRESUMO
Separation of the blood forms of trypanosomes from the blood of infected animals is difficult, especially in the case of Trypanosoma cruzi Y strain. Two procedures to isolate the Y strain blood forms of T. cruzi using polyvinyl pyrrolidone-coated silica (percoll) and histopaque are reported in this study. The recovery rates of parasites were 16 +/- 5 and 68 +/- 16%, respectively. The parasites isolated by these methods presented normal motility and morphology and were infective to albino mice with prepatent periods, parasitemia curves, and polymorphism patterns during the infection that were similar to those of control parasites. In addition, the preservation of surface antigens was confirmed by immunocytochemical studies.
Assuntos
Sangue/parasitologia , Trypanosoma cruzi/isolamento & purificação , Animais , Antígenos de Protozoários/análise , Centrifugação/métodos , Camundongos , Trypanosoma cruzi/imunologiaRESUMO
Six Plasmodium falciparum protein fractions, isolated under reducing conditions, were used to immunize mice, rabbits and the squirrel monkey Saimiri sciureus. Five or seven subcutaneous injections of each antigenic preparation, in conjunction with Freund's complete or incomplete adjuvants, were administered. This led to the development of specific antibodies detected by IFAT, ELISA or immunoblotting which inhibited merozoite reinvasion in in vitro P. falciparum cultures. This activity seems to be associated with rhoptry proteins contained in fractions Pf F2 and Pf F4.
Assuntos
Anticorpos Antiprotozoários/biossíntese , Antígenos de Protozoários/imunologia , Vacinas Antimaláricas/imunologia , Plasmodium falciparum/imunologia , Proteínas de Protozoários/imunologia , Animais , Anticorpos Antiprotozoários/imunologia , Feminino , Soros Imunes , Imunização Secundária , Imunoglobulina G/imunologia , Imunoglobulina M/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Plasmodium falciparum/crescimento & desenvolvimento , Coelhos , Saimiri , VacinaçãoRESUMO
Monoclonal antibodies raised against a strain of Leishmania infantum isolated in Greece were produced and tested for their protective effect in an in vivo system (in BALB/C mice). A single monoclonal antibody, IgG2b isotype, can prevent the development of two Leishmania strains in vivo: one of L. major and one of L. mexicana amazonensis. This antibody-mediated protection may be dependent on complement.