Strong Antigen-Specific T-Cell Response Is Associated with Age and Genetically Dependent Resistance to Avian Enteric Salmonellosis

• Published in: Infection and Immunity 2005-11, Vol.73 (11), p.7509-7516
• Main Authors: Beal, Richard K, Powers, Claire, Wigley, Paul, Barrow, Paul A, Kaiser, Pete, Smith, Adrian L
• Format: Article
• Language: English
• Subjects: Aging - immunology; Animals; Antibodies, Bacterial - blood; Bacterial diseases; Bacterial diseases of the digestive system and abdomen; Biological and medical sciences; Chickens - immunology; Chickens - microbiology; Fundamental and applied biological sciences. Psychology; Gastrointestinal Contents - microbiology; Gastrointestinal Diseases - genetics; Gastrointestinal Diseases - immunology; Gastrointestinal Diseases - microbiology; Gastrointestinal Diseases - veterinary; Genetic Predisposition to Disease; Human bacterial diseases; Infectious diseases; Liver - microbiology; Medical sciences; Microbial Immunity and Vaccines; Microbiology; Organ Specificity; Poultry Diseases - genetics; Poultry Diseases - immunology; Poultry Diseases - microbiology; Salmonella - isolation & purification; Salmonella enterica; Salmonella Infections, Animal - genetics; Salmonella Infections, Animal - immunology; Specific Pathogen-Free Organisms; Spleen - microbiology; T-Lymphocytes - immunology; Time Factors
• ISSN: 0019-9567; 1098-5522
• DOI: 10.1128/IAI.73.11.7509-7516.2005

Chicken genetics and age affect resistance to enteric infection with Salmonella enterica serovar Typhimurium and were used to identify the immune responses that may contribute to rapid clearance. When birds were infected at 40 days of age, line 6₁ chickens cleared the infection more effectively than line N chickens, whereas when birds were infected at 10 days of age, both chicken lines were highly susceptible to infection. Antibody levels, T-cell responsiveness, and cytokine mRNA levels were all elevated during infection. A negative correlation between resistance and antigen-specific antibody production was observed in older chickens. However, this finding was not replicated for age-related resistance; we found that older chickens exhibited a stronger and more rapid antibody response than younger chickens. The levels of interleukin-1{szligbeta} (IL-1{szligbeta}) and gamma interferon (IFN-[gamma]) mRNA were similar in the spleens and cecal tonsils of both line 6₁ and line N chickens, except for higher levels of IL-1{szligbeta} in the spleens of line 6₁ chickens at 6 days postinfection. Differences in the levels of IFN-[gamma] and IL-1{szligbeta} 1{szligbeta} mRNA between the lines were more apparent in younger chickens, but while the increases were greater than those observed in the older chickens, the clearance of enteric S. enterica serovar Typhimurium was much slower. The level of antigen-specific proliferation of splenocytes was associated with increased resistance in both experimental systems, and the strongest responses were observed in older and genetically resistant chickens. The data presented here implicate T-cell responses in the clearance of S. enterica serovar Typhimurium from the intestine of infected chickens.