Submitted to: Developmental and Comparative Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/17/1999
Publication Date: N/A
Interpretive Summary: Monitoring the differences in the phenotype of pig lymphocytes at the neonatal age constitutes a key factor in the understanding of the natural and pathological immune responses. A survey was conducted to accumulate information on the phenotype of lymphocytes isolated from eight different anatomical sites of the pig . The objective was to determine if the age of the animal and certain management practices such as weaning has an effect on the phenotype of lymphocytes from the peripheral blood (PBMC), mesenteric lymph nodes (MLN), lymphoid associated structures such as Peyer Patches and specialized lymphocytes localized in the Intraepithelial (IE) and Lamina Propria (LP)compartments of the pig small intestine. Different populations were characterized by flow cytometry analysis using a broad panel of specific monoclonal antibodies against lymphoid surface antigens that stain porcine lymphocytes. A statistical analysis of the data collected was used to examine the effect of age and weaning on the lymphocyte phenotype. Significant differences were detected when surface antigens were compared before and after the weaning. Similarly, age of the pig and site of isolation were also identified as factors that affect the phenotype of lymphoid cells. Taken together, the results of these analyses are important to the scientific community that is interested in identifying predisposing factors that influence the immune responses of pigs at the mucosal level.
Technical Abstract: The objective of this study was to identify the effect of age and certain management procedures, such as weaning on the phenotype of lymphocytes isolated from the peripheral blood mononuclear cells (PBMC), mesenteric lymph nodes (MLN), Peyer Patches of jejunum (jejPP) and ileum (ilPP), Intraepithelial (IE) and Lamina Propria (LP) compartments of the jejunum and ileum. A group of forty- two pigs from a high health commercial farm and 13 miniature swine from an experimental farm were used as donors for the tissues examined. Purified cell populations were identified after immunostaining with the pan lymphocyte CD45 surface antigen. Each population was characterized using monoclonal antibodies to cell surface antigens (CD21,CD4, CD8, DP CD4/CD8, CD16, CD21,gdTCR receptor, CD16,and SWC3)and to activation surface antigens(SLA-DQ and CD25 mean channels). A complete randomized block design with unequal replications was statistically analyzed to monitor the changes in all surface antigens in different tissues within the age group. Results indicated that the source of the pigs used for the comparisons had some differences in the cell yields. The percentage of T-cells varied according to the site of isolation (p<0.05). The age and weaning also had an effect on the phenotype of cells. Thus, our results suggest that neonatal pigs have developmental changes in the pool of immune cells at mucosal sites. Since these cells regulate cellular interactions and production of immune stimulatory cytokines, their relative percentages can clearly influence disease and vaccine responses.