RESUMO
To ascertain the in vivo role of mycobacterial lipids phthiocerol dimycocerosates (PDIM) in experimental murine tuberculosis (Tb), airways infection was used to compare the parental virulent clinical isolate MT103 with its mutant fadD26, lacking PDIM. Lungs were assessed as the Tb-target organ and mediastinal lymph nodes as the corresponding lymphoid tissue, in order to quantify: the major T-cell subsets (CD4+/CD8+/gammadelta+) and their activation kinetics, bacillary burden, and in vivo cytotoxicity against inoculated target cells loaded with mycobacterial Ags. After 4 weeks, infection augmented total and activated CD4+ and CD8+ T cells in lungs and nodes mainly with MT103, while gammadelta+ T cells increased earlier in nodes. MT103 bacillary burden was bigger and appeared earlier than the mutant fadD26, especially in the lung than in mediastinal nodes. At day 14 of MT103 infection, there was no cytotoxicity in lungs and nodes; while with fadD26 there was some in the nodes. At day 21 of MT103 infection, important cytotoxicity was detected only in lungs; while with fadD26 both tissues showed important activity. Interestingly, unlike the infection with fadD26, cytotoxicity under MT103 fell considerably in the target organ (lung) from days 21 to 60, the advanced phase. Although upon airways infection both mycobacteria behaved similarly regarding T cell (CD4/CD8/gammadelta) stimulation kinetics; they differed in the magnitude of these responses, in the bacterial load within tissues, and to trigger in vivo cytotoxicity in lungs and regional lymph nodes. This highlights the relevance of certain mycobacterial lipids to modify crucial effector branches of immunity.
Assuntos
Citotoxicidade Imunológica , Lipídeos/fisiologia , Pulmão/imunologia , Linfonodos/imunologia , Linfócitos T/imunologia , Tuberculose/imunologia , Animais , Hipersensibilidade Tardia , Ativação Linfocitária , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Tuberculose/microbiologiaRESUMO
Thalidomide is a drug that is being used in several diseases with an immunological component, but the effects on the different immune functions have only been studied partially. Therefore, we studied the effect of thalidomide on PPD-or Con-A-induced proliferation of human mononuclear cells. We found no direct effect of thalidomide at up to 50 micrograms/ml on the cultures. Cells taken from subjects 6 h after ingestion of 200 mg of thalidomide proliferated equally well to PPD and Con-A than cells taken prior to drug administration. Plasma taken from subjects that ingested 200 mg of thalidomide 6 h before did not affect the proliferative response of their own cells when added to the cultures. Plasma from rabbits that were injected with doses 5 or 15 times higher than the dose given to humans did not diminish the proliferative response of human mononuclear cells to PPD. We conclude that neither thalidomide nor its metabolites affect the proliferative response of human mononuclear cells.