NK-like CD8(+) cells in immunologically naïve neonatal calves that respond to dendritic cells infected with Mycobacterium bovis BCG.
Pre-exposure to environmental mycobacteria and induction of an inappropriately biased immune response may be major factors affecting the efficacy of BCG; vaccination of neonates that have not been exposed to environmental mycobacteria may induce more effective immunity. Responses of neonatal calves to mycobacterial antigens using dendritic cells (DC) as antigen-presenting cells were investigated. In nonvaccinated, immunologically naive calves as young as 1 day old, a population of CD8(+) cells proliferated and produced IFN-gamma in response to BCG-infected DC. CD3(-) CD8(+) NK-like and CD3(+) CD8(+) T cells were evident within the responding CD8(+) population. The response was not MHC-restricted. The NK-like CD3(-) cells were the major population producing IFN-gamma. The presence of mycobacteria-reactive, IFN-gamma-secreting CD8(+) NK cells in neonatal calves may have important consequences for the induction of a Th1-biased immune response.
Hope
Jayne C
JC
Institute for Animal Health, Compton, Newbury, Berkshire, United Kingdom. Jayne.Hope@BBSRC.ac.uk
Sopp
Paul
P
Howard
Chris J
CJ
D000818:Animals; D000831:Animals, Newborn; D017951:Antigen Presentation; D001500:BCG Vaccine; D016827:CD8 Antigens; D002417:Cattle; D003602:Cytotoxicity, Immunologic; D003713:Dendritic Cells / Q000276:immunology*; D007109:Immunity; D007694:Killer Cells, Natural / Q000276:immunology*; D009163:Mycobacterium bovis / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology; D014380:Tuberculosis, Bovine / Q000276:immunology / Q000517:prevention & control
D001500:BCG Vaccine; D016827:CD8 Antigens