The current study compares the proportion and distribution of T lymphocyte subsets in the GALT tissues such as jejunal lamina propria (JLP), ileal Peyer's patches (IPP), and mesenteric lymph node (MLN) and relates it to the development of immune maturity/competence in conventionally reared suckling and weaned pigs. A mild (MLN) decrease of CD2a^+ T cells was observed in immunologically mature (8-week-old) pigs. In 8-week-old pigs CD4a^+ helper T cells were significantly increased (25 times) in JLP, whereas these cells were decreased (2 times) in the IPP. Cytolytic CD8a^+ T cells were more numerous (2-fold) in JLP of 8-week-old pigs. CD25^+ mature T cells or blasts were present in lower percentages (2 times) in IPP of 8-week-old pigs. Species-specific SWC1a^+ T cells were more frequent in the MLN, and IPP of 4-week-old pigs as compared to the quantities of these cells in 8-week-old pigs. Age-related decrease of SWC1^+ cells was detected in all tissues tested. The production rate of T cells within the porcine tissues tested in the current study seems to be dependent of both age and contacts with microbial and fed antigens presented via the skin and mucosal surfaces.

Veterinary medicine