ABSTRACT
Viable metacyclic forms of T. cruzi, Y strain, treated with an adequate dose of actinomycin D (50 micrograms Act-D/ml/10(7) parasites/ml for 72 h at 28 degrees C) showed the following properties: 1) they lost their ability to replicate in culture medium, in blood and in tissues of normal mice and were no longer able to incorporate tritiated thymidine; 2) they could not penetrate into Vero cells and could not replicate inside normal macrophages; 3) they retained their immunogenicity and the ability to protect mice against a virulent infection; 4) they did not induce histological lesions as described in chronic experimental Chagas' disease.
Subject(s)
Antiprotozoal Agents , Chagas Disease/physiopathology , Dactinomycin/pharmacology , Trypanosoma cruzi/drug effects , Animals , DNA Replication/drug effects , Female , Macrophages/parasitology , Mice , Mice, Inbred BALB C , Trypanosoma cruzi/pathogenicity , Trypanosoma cruzi/physiology , Vero CellsABSTRACT
The subcutaneous (s.c.) vaccination of DBA/2 mice with 4 weekly doses of 3 x 10(7) living metacyclic forms of T. cruzi, Y strain, obtained from culture in axenic medium and treated for 24 h with actinomycin-D (50 micrograms/10(7) parasites), a drug that promotes an irreversible blockade of the parasite replication, do not induce any detectable degree of humoral and cellular immunosuppression as assessed by a) the production of anti-SRBC antibodies, b) the permanence of delayed cutaneous reaction to T. cruzi antigen, to PPD and DNCB and c) the degree of blastogenic transformation of spleen lymphocytes in the presence of the specific antigen.
Subject(s)
Dactinomycin/pharmacology , Immune Tolerance/immunology , Trypanosoma cruzi/immunology , Vaccination , Animals , Antibody Formation , Antigens, Protozoan/immunology , Female , Hemolytic Plaque Technique , Hypersensitivity, Delayed , Immunity, Cellular , Lymphocyte Activation/immunology , Mice , Mice, Inbred DBAABSTRACT
O BCG, em soluçäo lipídica, injetado por via intravenosa, foi capaz de reverter a imunosupressäo humoral provocada pelo mastocitoma P-815, em camundongos singênicos DBA/2, aumentando tanto o número de células formadoras de placas hemolíticas quanto os títulos de anticorpos hemaglutinantes do soro. Näo foram encontradas diferenças significativas nos títulos de anticorpos hemaglutinantes da classe IgG. Nenhum efeito bloqueador pôde ser notado na progressäo normal do tumor
Subject(s)
Mice , Animals , Female , Antibody Formation , Immunoglobulin G , Mast-Cell Sarcoma/immunology , Mycobacterium bovis , Hemolytic Plaque Technique , Mice, Inbred DBAABSTRACT
Viable BCG bacilli, in a lipid emulsion, inoculated intravenously, were capable of reverting the profound humoral immunosuppression induced in adult DBA/2 mice by the mastocytoma P-815. BCG increased not only the number of hemolytic plaque forming cells, but also the serum titers of hemagglutinating IgM antibodies. However, no blocking effect was detected on normal tumor progression.
Subject(s)
Immunoglobulin M/metabolism , Mast-Cell Sarcoma/immunology , Mycobacterium bovis/immunology , Animals , Antibody Formation , Female , Hemolytic Plaque Technique , Mice , Mice, Inbred DBAABSTRACT
Avaliou-se em coelhos e camundongos, a atividade imunogenica e protetora de um extrato antigenico de Schistosoma mansoni, obtido pela estocagem de vermes adultos em solucao salina tamponada (Extrato Salino).A imunizacao dos animais determinuou o desenvolvimento de resposta imune celular e humoral, avaliada por provas especificas.Todos os coelhos imunizados com ES, desenvolveram altos niveis de anticorpo citotoxico (91 a 100%), determinados pela avaliacao de atividade citotoxica in vitro, contra esquistosomulos. Concluiu-se que os coelhos e camundongos imunizados com o extrato salino apresentaram diminuicao da carga parasitaria oriunda da infeccao posterior com cercarias de S. mansoni, em relacao aos controles. Os percentuais de protecao foram de 88.6% e 54% para os animais vacinados (coelhos e camundongos respectivamente)
Subject(s)
Animals , Mice , Antigens , Schistosoma mansoni , Schistosomiasis , Immunization , RabbitsSubject(s)
Infant, Newborn , Humans , Male , Female , Antibody Formation , BCG Vaccine , Immunity, CellularSubject(s)
Infant , Child, Preschool , Humans , Male , Female , Antibody Formation , BCG Vaccine , Immunity, CellularABSTRACT
Estudos imunologicos foram realizados em 16 pacientes adultos, de ambos os sexos, acometidos de paracoccidioidomicose. Dentre os achados mais importantes figuram os teores elevados de IgG, a baixa do 3o. componente do complemento, a presenca de anticorpos precipitantes e hemaglutinantes contra a paracoccidioidina, a presenca de complexos imunes circulantes, baixos teores de linfocitos T circulantes, teores normais de linfocitos T supressores e hiporreatividade dos linfocitos T a fitohemaglutinina e a paracoccidioidina.A histologia das reacoes cutaneas a paracoccidioidina acusou um aspecto semelhante ao da reacao de Arthus, com o maximo de intensidade do eritema em 24 horas, a presenca de vasculite e a infiltracao predominante por polimorfonucleares
Subject(s)
Paracoccidioidomycosis , Immunoglobulin G , Skin Tests , T-LymphocytesABSTRACT
Studies were carried out with a polyribosomal fraction isolated from Trypanosoma cruzi Y epimastigotes, with the intention to determine both its immunogenic activity and the degree of protection it could induce against experimental T. cruzi infection. This fraction was assayed in four groups of mice by using different schedules of vaccination and varying the dose, intervals, and route of administration. Seven days after the last dose, the animals were sacrificed for immunological studies or subjected to challenge with T. cruzi trypomastigotes. The results obtained in all schedules showed that our polyribosomal fraction only induced a weak antibody response, but was capable of evoking an expressive cellular response. It was also shown that this fraction has the capacity of inducing a high degree of protection against T. cruzi infection, as determined by the decrease of parasitemia and the prolonged survival time of immunized animals.
Subject(s)
Immunity, Cellular , Polyribosomes/immunology , Trypanosoma cruzi/immunology , Animals , B-Lymphocytes/immunology , Female , Mice , Trypanosoma cruzi/ultrastructure , VaccinationABSTRACT
It was shown that, in physiological concentrations, insulin enhances, in vitro, the immunological phagocytosis of sensitized sheep erythrocytes by cultured mouse peritoneal macrophages. Insulin seems to stimulate macrophage phagocytosis as a cholinomimetic agonist by increasing the intracellular levels of cyclic GMP.
Subject(s)
Insulin/pharmacology , Macrophages/drug effects , Phagocytosis/drug effects , Animals , Binding Sites , Female , Insulin Antagonists , Macrophages/immunology , Macrophages/physiology , Mice , Nucleotides, Cyclic/metabolism , Stimulation, ChemicalABSTRACT
Studies were carried out with the leukocyte migration inhibition tests using soluble and particulate antigens (PPD, somatic antigens of T. cruzi, M. bovis (BCG) and leukocytes from patients sensitized to PPD and patients with chronic Chagas' disease. The results obtained showed that the stimulatory capacity of particulate antigens are greater than that of soluble antigens.
Subject(s)
Leukocytes/immunology , Macrophage Migration-Inhibitory Factors , T-Lymphocytes/immunology , Antigens , Humans , Mycobacterium bovis/immunology , Mycobacterium tuberculosis/immunology , Trypanosoma cruzi/immunologyABSTRACT
The humoral and cellular immunity of 23 children with ages between 1 and 5 years, nonreactors to 10 mu of PPD, were investigated after oral vaccination with one dose of 100 mg of fresh oral BCG, Rio de Janeiro strain (Moreau strain). The tests performed shortly before and 70 days after vaccination showed that the schedule used was neither sufficient to stimulate the production of antibody anti-PPD, nor to change the levels of serum immunoglobulins and T, T-active and B blood lymphocytes. However, about 60% of the children became responsive to 10 mu of PPD after treatment and all gave positive reactions to PPD on "in vitro" assays of leukocyte migration inhibition. New schedules for oral vaccination with fresh BCG are in progress in our laboratory.