Gamma/delta T cell response of chickens after oral administration of attenuated and non-attenuated Salmonella typhimurium strains.
Poultry represents an important source of Salmonella infection in man. Despite intensive research on immunity, little is known about the involvement of T cell sub-populations in the immunological response of chickens against infection with non-host-adapted Salmonella (S.) serovars. In this study, the T cell composition of blood lymphocytes (CD4(+)CD8(+); CD4(+)CD8(-); CD4(-)CD8(+); CD8(+)TcR1(+); CD8(-)TcR1(+), CD8(+)TcR1(-)) after oral administration of the non-attenuated S. typhimurium wild-type strain 421 (infection) or the attenuated vaccine strain Salmonella vac((R)) T (immunization) to day-old chicks was investigated and compared with non-treated chickens by flow cytofluorometry. Additionally, the occurrence of T cell sub-populations (CD4(+); CD8(+); TcR1(+)(gammadelta); TcR2(+)(alphabeta(1))) in ceca, spleen and bursa of Fabricius of the birds was studied immunohistologically. Blood samples and tissues were examined between days 1 and 12 of age. Chicks inoculated with S. typhimurium 421 or Salmonella vac((R)) T showed significantly elevated percentages of CD8(+)TcR1(+) in blood on days 7, 8 and 9, or on day 8 in comparison to control animals. The CD4 to CD8 cell ratio was about 3:1 in infected animals on day 5 of age. In the organs of treated chicks the numbers of CD8(+)(gammadelta) and TcR1(+)(gammadelta) cells had markedly increased on days 4 and 5 in ceca, 8 and 9 in the bursa and 9 and 12 in the spleen. Moreover, infected or vaccinated birds revealed larger quantities of CD4(+) and TcR2(+) T cells in ceca on days 4 and 5. As shown by double staining, the TcR1(+) cells in the organs of infected animals additionally carried the CD8 antigen. In conclusion, immunization of day-old chicks with the attenuated Salmonella live vaccine strain resulted in the same changes in T cell composition as seen after infection with the non-attenuated Salmonella wild-type strain, but at a lower level. The remarkable increase of CD8(+)TcR1(+)(gammadelta) double positive cells in treated birds indicates an important role of this cell sub-population in the immunological defense of chickens against Salmonella exposure.
Berndt
A
A
Federal Institute for Health Protection of Consumers and Veterinary Medicine, Division 4, Naumburger Strasse 96a, D-07743, Jena, Germany. a.berndt@bgvv.de
Methner
U
U
D000818:Animals; D002060:Bursa of Fabricius / Q000276:immunology; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002432:Cecum / Q000276:immunology; D002645:Chickens / Q000276:immunology*; D005434:Flow Cytometry / Q000662:veterinary; D007150:Immunohistochemistry; D016131:Lymphocyte Subsets / Q000145:classification / Q000276:immunology; D011201:Poultry Diseases / Q000276:immunology* / Q000382:microbiology / Q000517:prevention & control; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology*; D012481:Salmonella Infections, Animal / Q000276:immunology* / Q000382:microbiology / Q000517:prevention & control; D022562:Salmonella Vaccines / Q000276:immunology / Q000592:standards; D012486:Salmonella typhimurium / Q000276:immunology*; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000276:immunology; D014611:Vaccination / Q000662:veterinary
D016692:Receptors, Antigen, T-Cell, gamma-delta; D022562:Salmonella Vaccines