TUMOR-NECROSIS-FACTOR-ALPHA (TNF-ALPHA) IN THE HOST-RESISTANCE TO MYCOBACTERIA OF DISTINCT VIRULENCE

• Tipo: Artigo em Revista Científica Internacional
• Data: 1995

Autores

APPELBERG, R (Autor) ICBAS; SARMENTO, A (Autor) Outra; CASTRO, AG (Autor) Outra

Revista

Título: Clinical and Experimental Immunology

Vol. 101

Páginas: 308-313

ISSN: 0009-9104

Editora: Wiley-Blackwell

Indexação

ISI Web of Knowledge - 34 Citações

Scopus - 34 Citações

Classificação Científica

FOS: Ciências médicas e da saúde > Medicina básica

Outras Informações

ID Authenticus: P-001-GGP

Abstract (EN): The relative virulence of different isolates of Mycobacterium avium has been linked to their capacity to trigger the secretion of TNF from the macrophages they infect. Smooth opaque (SmOp) variants of Myco. avium have been shown to trigger higher expression of TNF-alpha by macrophages in vitro than the smooth transparent (SmTr) variants. To analyse the role of TNF in resistance to infection by Myco. avium, we studied the infection by two different morphotypes of strain 2.151 of Myco. avium both in vitro and in vivo in the presence or absence of neutralizing antibodies to TNF. No effects were found in vitro regarding the growth of either isolate of Myco. avium. In vivo, only the virulent SmTr morphotype showed enhanced growth in the presence of the neutralizing antibodies. This enhancement occurred relatively late when priming for TNF secretion in vivo was evident. Among four isolates of Il Myco. avium, three virulent ones induced a marked priming for TNF release and one avirulent strain did not. il Mycobacterium tuberculosis H37Ra, which is very active in inducing TNF release due to its lipoarabinomannan moiety, was used to compare with the previous results. The growth of H37Ra in macrophages was increased in vitro by the neutralization of TNF and neutralization of either TNF and/or interferon-gamma (IFN-gamma) enhanced the in vivo proliferation of this microbe in the spleen and liver of infected animals, whereas only the combination of both anti-TNF and anti-IFN-gamma enhanced bacterial proliferation in the lung. We conclude that resistance to the avirulent strains of Myco. avium did not involve TNF, but rather antimicrobial mechanisms expressed consitutively in the mononuclear phagocytes. In contrast, TNF plays an important role in the control of Myco, tuberculosis H37Ra infection.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 6