Inhibition of NF-kappa B activity in T and NK cells results in defective effector cell expansion and production of IFN-gamma required for resistance to Toxoplasma gondii.
To define the role of NF-kappa B in the development of T cell responses required for resistance to Toxoplasma gondii, mice in which T cells are transgenic for a degradation-resistant (Delta N) form of I kappa B alpha, an inhibitor of NF-kappa B, were challenged with T. gondii and their response to infection compared with control mice. I kappa B alpha(Delta N)-transgenic (Tg) mice succumbed to T. gondii infection between days 12 and 35, and death was associated with an increased parasite burden compared with wild-type (Wt) controls. Analysis of the responses of infected mice revealed that IL-12 responses were comparable between strains, but Tg mice had a marked reduction in systemic levels of IFN-gamma, the major mediator of resistance to T. gondii. In addition, the infection-induced increase in NK cell activity observed in Wt mice was absent from Tg mice and this correlated with NK cell expression of the transgene. Infection-induced activation of CD4(+) T cells was similar in Wt and Tg mice, but expansion of activated CD4(+)T cells was markedly reduced in the Tg mice. This difference in T cell numbers correlated with a reduced capacity of these cells to proliferate after stimulation and was associated with a major defect in the ability of CD4(+) T cells from infected mice to produce IFN-gamma. Together, these studies reveal that inhibition of NF-kappa B activity in T and NK cells results in defective effector cell expansion and production of IFN-gamma required for resistance to T. gondii.
Tato
Cristina M
CM
Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Villarino
Alejandro
A
Caamaño
Jorge H
JH
Boothby
Mark
M
Hunter
Christopher A
CA
D000818:Animals; D000953:Antigens, Protozoan / Q000494:pharmacology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology; D002455:Cell Division / Q000235:genetics / Q000276:immunology; D003602:Cytotoxicity, Immunologic / Q000235:genetics; D005260:Female; D020022:Genetic Predisposition to Disease; D020672:I-kappa B Proteins / Q000235:genetics; D007113:Immunity, Innate / Q000235:genetics; D007371:Interferon-gamma / Q000096:biosynthesis* / Q000502:physiology; D007694:Killer Cells, Natural / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology; D008213:Lymphocyte Activation / Q000235:genetics / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008822:Mice, Transgenic; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014122:Toxoplasma / Q000276:immunology; D014124:Toxoplasmosis, Animal / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D019076:Transgenes / Q000276:immunology
D000953:Antigens, Protozoan; D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606205:Nfkbia protein, mouse; D000072000:NF-KappaB Inhibitor alpha; D007371:Interferon-gamma