Microbiological and Product Quality Consequences of Housing Laying Hens in Production Systems
Location: Egg Safety and Quality
Title: Changes in Peyer’s Patch and Cecal Tonsil B Lymphocytes in Laying Hens Following Challenge with Salmonella enterica serovar Enteritidis
Submitted to: International Journal of Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 17, 2011
Publication Date: April 1, 2011
Citation: Holt, P.S., Vaughn, L., Gast, R.K. 2011. Changes in Peyer’s Patch and Cecal Tonsil B Lymphocytes in Laying Hens Following Challenge with Salmonella enterica serovar Enteritidis. International Journal of Poultry Science. 10: 231-237.
Interpretive Summary: Peyer’s patches (PP) and cecal tonsils (CT) are two important tissues for eliciting protective immune responses against pathogens in the intestinal tract of chickens. Two trials were conducted to examine the changes that occur in the B cell populations, the cells responsible for making antibodies, of PP and CT of laying hens following infection with Salmonella enterica serovar Enteritidis (SE). This organism has been responsible for a number food-borne outbreaks of human salmonellosis resulting from consumption of contaminated eggs produced by infected hens. A strong antibody response against SE in the intestinal tract can help reduce the chance for the organism to become established in the chicken gut and travel to the egg. Tissue differences were observed between PP and CT with regards to two antibody classes, IgM and IgA, but this changed following infection. In contrast, the IgG class of antibody was not different between the two tissue types prior to infection but following an SE challenge, significant differences between PP and CT could be observed. These results indicate that the B cell populations in the PP and CT are not static but are in a dynamic state of flux in response to environmental stimuli such as SE infection.
Two trials were conducted to determine B cell changes in Peyer’s patches (PP) and cecal tonsils (CT) of specific-pathogen-free Single Comb White Leghorn hens challenged with Salmonella enterica serovar Enteritidis (SE). Prior to challenge and then weekly post challenge, 4 or 3hens in Trials 1 and 2, respectively, were sacrificed and their intestinal tracts excised. Cells were purified from proximal and distal PP along with both CT and then aliquots of cells were incubated with antibodies to chicken immunoglobulins IgM, IgG, and IgA. The B cells expressing the different immunoglobulin isotypes were identified via flow cytometric analysis. B lymphocytes expressing IgM were most prevalent, representing 40-60% and 30-50% of CT and PP B cells, respectively, while 20-30% of CT and PP lymphocytes expressed IgA. Only a small percentage of CT and PP lymphocytes, <10%, expressed IgG. Significantly more IgM+ cells were detected in CT vs proximal and distal PP and proximal PP in trials 1 and 2, respectively. Significantly more IgA+ cells were observed in proximal PP vs distal PP and CT in trial 1 but not in trial 2. Following SE infection, these differences were no longer observed. For IgG+ cells, however, no significant differences between tissues were observed prior to challenge but significantly more IgG+ cells were observed in both PP vs CT at weeks 1 and 3 post challenge in trial 1 and week 1 post challenge in trial 2. These results indicate that B lymphocyte differences do occur in PP vs CT in adult chickens and these populations can change in response to stimuli such as intestinal infection.