Transmembrane TNF induces an efficient cell-mediated immunity and resistance to Mycobacterium bovis bacillus Calmette-Guérin infection in the absence of secreted TNF and lymphotoxin-alpha.
The contribution of a transmembrane (Tm) form of TNF to protective immunity against Mycobacterium bovis bacillus Calmette-Guérin (BCG) was studied in transgenic (tg) mice expressing a noncleavable Tm TNF but lacking the TNF/lymphotoxin-alpha (LT-alpha) locus (Tm TNF tg mice). These mice were as resistant to BCG infection as wild-type mice, whereas TNF/LT-alpha(-/-), TNF(-/-), and LT-alpha(-/-) mice succumbed. Tm TNF tg mice developed granulomas of smaller size but at 2- to 4-fold increased frequencies compared with wild-type mice. Granulomas were mainly formed by monocytes and activated macrophages expressing Tm TNF mRNA and accumulating acid phosphatase. NO synthase 2 activation as a key macrophage bactericidal mechanism was low during the acute phase of infection in Tm TNF tg mice but was still sufficient to limit bacterial growth and increased in late infection. While infection with virulent Mycobacterium tuberculosis resulted in very rapid death of TNF/LT-alpha(-/-) mice, it also resulted in survival of Tm TNF tg mice which presented an increase in the number of CFU in spleen (5-fold) and lungs (10-fold) as compared with bacterial load of wild-type mice. In conclusion, the Tm form of TNF induces an efficient cell-mediated immunity and total resistance against BCG even in the absence of LT-alpha and secreted TNF. However, Tm TNF-mediated protection against virulent M. tuberculosis infection can also be efficient but not as strong as in BCG infection, in which cognate cellular interactions may play a more predominant role in providing long-term surveillance and containment of BCG-infected macrophages.
Olleros
Maria L
ML
Department of Pathology, University of Geneva, Geneva, Switzerland.
Guler
Reto
R
Corazza
Nadia
N
Vesin
Dominique
D
Eugster
Hans-Pietro
HP
Marchal
Gilles
G
Chavarot
Pierre
P
Mueller
Christoph
C
Garcia
Irene
I
D000818:Animals; D000942:Antigens, Bacterial / Q000494:pharmacology; D001770:Blood Bactericidal Activity / Q000235:genetics / Q000276:immunology; D015169:Colony Count, Microbial; D016207:Cytokines / Q000096:biosynthesis / Q000097:blood; D006099:Granuloma / Q000235:genetics / Q000276:immunology; D007111:Immunity, Cellular / Q000235:genetics; D007113:Immunity, Innate / Q000235:genetics; D007371:Interferon-gamma / Q000096:biosynthesis; D007424:Intracellular Fluid / Q000276:immunology / Q000382:microbiology; D008233:Lymphotoxin-alpha / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D008565:Membrane Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009163:Mycobacterium bovis / Q000254:growth & development / Q000276:immunology* / Q000472:pathogenicity; D009569:Nitric Oxide / Q000096:biosynthesis; D013154:Spleen / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D016019:Survival Analysis; D018417:Th1 Cells / Q000276:immunology / Q000378:metabolism; D019076:Transgenes / Q000276:immunology; D014376:Tuberculosis / Q000235:genetics / Q000276:immunology* / Q000382:microbiology / Q000401:mortality; D014409:Tumor Necrosis Factor-alpha / Q000172:deficiency / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014774:Virulence
D000942:Antigens, Bacterial; D016207:Cytokines; D008233:Lymphotoxin-alpha; D008565:Membrane Proteins; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D007371:Interferon-gamma