Gain of function in Mycobacterium bovis BCG Moreau due to loss of a transcriptional repressor

The Bacille Calmette-Guérin (BCG) vaccine comprises a family of genetically different strains derived by the loss of genomic regions (RDs) and other mutations. In BCG Moreau, loss of RD16 inactivates rv3405c * , encoding a transcriptional repressor that negatively regulates the expression of Rv3406, an alkyl sulfatase. To evaluate the impact of this loss on the BCG and host cell viability and the cytokine profile, THP-1 cells were infected with BCG Moreau (harbouring the empty vector) and a complemented strain carrying a functional copy of rv3405c. Viability of the host cells and bacteria as well as the pattern of cytokine secretion were evaluated. Our results show that the viability of BCG Moreau is higher than that of the complemented strain in an axenic medium, suggesting a possible functional gain associated with the constitutive expression of Rv3406. Viability of the host cells did not vary significantly between recombinant strains, but differences in the profiles of the cytokine secretion (IL-1β and IL-6) were observed. Our results suggest an example of a functional gain due to gene loss contributing to the elucidation of the impact of RD16 on the physiology of BCG Moreau.

Analise da conversao da reacao de mitsuda nas formas multibacilares da hanseniase / An analysis of mitsuda reactions conversion in multi-bacillar forms of hansen's disease

Com o objetivo de verificar o percentual de conversao imunologica atraves da reacao de Mitsuda e realizar a analise de fatores envolvidos nesse processo, selecionou-se ex-pacientes portadores de hanseniase atendidos na Fundacao Alfredo da Matta (Manaus-AM), com as seguintes caracteristicas: forma clinica multibacilar, reacao de Mitsuda negativo no diagnostico, alta por cura no periodo de 1989 a 1993, sem tratamento especifico anterior e que fizeram uso de esquemas poliquimioterapicos (PQT) com regularidade. Os participantes foram dispostos em dois grupos conforme esquema PQT: 22 haviam feito uso do esquema da OMS (PQT/OMS), isto e, ate negativacao baciloscopica, e 24 utilizaram o esquema de duracao fixa (PQT/DF), com ingestacao de 24 doses. Todos foram reavaliados, em 1997, atraves de exame clinico-dermatoneurologico, baciloscopia da pele, grau de incapacidade e aplicacao de novo reacao de Mitsuda com posterior leitura. Constatou-se que entre os individuos classificados como portadores de hanseniase Virchowiana nao ocorreu nenhuma variacao de resposta imunologica celular, medida pela reacao de Mitsuda. Entretanto, nas demais formas e principalmente nos pacientes que fizeram uso de PQT/DF, a conversao ocorreu com maior frequencia a medida que o paciente, na classificacao de Ridley e Jopling, estava mais proximo do polo imunocompetente. Em relacao ao Indice Baciloscopico verificou-se que a negativacao baciloscopica precoce pode ter enterferido na conversao da Reacao de Mitsuda. A correlacao dos dados retrospectivos e os obtidos na reavalicao contemporanea permitiu concluir que estas conversoes, embora frequentes, nao estao relacionadas com o esquema poliquimioterapico utilizado, a presenca ou nao de reacao reversa ou com o grau de incapacidade induzido pela hanseniase.

Recurrent aphthous stomatitis: a placebo-controlled clinical trial employing BCG

Realizamos estudo clínico terapêutico em 31 pacientes portadores de estomatite aftosa recorrente utilizando uma suspensäo oral de BCG. Os resultados obtidos mostraram que o BCG pode constituir uma ferramenta adicional no tratamento dos quadros severos de estomatite aftosa, especialmente em mulheres, embora sua açäo imunomoduladora necessite maiores investigaçöes. Nenhum efeito adverso foi relatado ou percebido durante o curso da terapêutica

Production of tumor necrosis factor by intravesical administration of bacillus Calmette Guerin in patients with superficial bladder cancer

Although an immune response to bacillus Calmette Guerin (BCG) has often been associated with antitumor activity, the action mechanism(s) of intravesical BCG therapy for prophylaxis and treatment of superficial bladder cancer is not clearly understood. In an attempt to evaluate the roles of tumor necrosis factor (TNF)-alpha and lymphotoxin (LT) in the antitumor activity, TNF-alpha productivities by peripheral blood monocytes, serum levels of TNF-alpha, and LT productivities by peripheral blood lymphocytes were studied in superficial bladder cancer patients after six intravesical administrations of BCG. TNF-alpha productivities by peritoneal macrophages of guinea pigs were also studied after six intravesical administrations of BCG. The maximum TNF-alpha productivities by peripheral blood monocytes of superficial bladder cancer patients were seen after the fourth week of administration of BCG, and the serum TNF-alpha levels were also slightly increased after intravesical BCG administration in the superficial bladder cancer patients. LT productivities by peripheral blood lymphocytes of superficial bladder cancer patients were significantly enhanced and the maximum LT productivity was also seen after the third or fifth BCG administration. TNF-alpha productivities by peritoneal macrophages of guinea pigs were significantly enhanced and the maximum TNF-alpha productivity was seen after the second or third BCG administration. Our data might suggest that six consecutive intravesical BCG administrations could induce the increased productions of TNF-alpha and LT, which might play an important role in the antitumor activity in superficial bladder cancer.Although an immune response to bacillus Calmette Guerin (BCG) has often been associated with antitumor activity, the action mechanism(s) of intravesical BCG therapy for prophylaxis and treatment of superficial bladder cancer is not clearly understood. In an attempt to evaluate the roles of tumor necrosis factor (TNF)-alpha and lymphotoxin (LT) in the antitumor activity, TNF-alpha productivities by peripheral blood monocytes, serum levels of TNF-alpha, and LT productivities by peripheral blood lymphocytes were studied in superficial bladder cancer patients after six intravesical administrations of BCG. TNF-alpha productivities by peritoneal macrophages of guinea pigs were also studied after six intravesical administrations of BCG. The maximum TNF-alpha productivities by peripheral blood monocytes of superficial bladder cancer patients were seen after the fourth week of administration of BCG, and the serum TNF-alpha levels were also slightly increased after intravesical BCG administration in the superficial bladder cancer patients. LT productivities by peripheral blood lymphocytes of superficial bladder cancer patients were significantly enhanced and the maximum LT productivity was also seen after the third or fifth BCG administration. TNF-alpha productivities by peritoneal macrophages of guinea pigs were significantly enhanced and the maximum TNF-alpha productivity was seen after the second or third BCG administration. Our data might suggest that six consecutive intravesical BCG administrations could induce the increased productions of TNF-alpha and LT, which might play an important role in the antitumor activity in superficial bladder cancer.

Superoxide-independent hydrogen peroxide release by activated macrophages

The present data show that freshly explanted BCG-activated mouse peritoneal macrophages release large quantities of hydrogen peroxide upon initial contact with a foreign substratum, without the requirement for other membrane stimuli such as phorbol diesters. The hydrogen peroxide detected under these conditions does not originate from extracellularly released superoxide, since 2 x 10**5 BCG-activated macrophages spontaneously released 1.6 nmol hydrogen peroxide but only 0.2 nmol superoxide. Thus, more than 90% of the hydrogen peroxide detected was not derived from extracellular superoxide dismutation. The dissociation between hydrogen peroxide and superoxide release was further demonstrated in cytochalasin B- or lidocaine-treated cells or in the absence of glucose. Under these conditions, hydrogen peroxide release was markedly inhibited while superoxide release was unaffected. These observations provide evidence that another metabolic pathway is involved in the generation and release of hydrogen peroxide during adherence and spreading of freshly explanted activated macrophages onto a substratum