Production of cytokines by lymphocytes from spleen, mesenteric lymph node and intestinal lamina propria of pigs.

Large numbers of cells can be recovered from pig intestine with phenotypes suggesting lamina propria rather than intraepithelial origin. Following activation with concanavalin A these cells produced a T-cell growth factor (TCGF) activity which was not inhibited in the presence of a monoclonal antibody recognizing pig interleukin-2 receptors (IL-2R). In contrast, the activity of recombinant human IL-2 and of supernatants from activated spleen cells was almost entirely inhibited by anti-IL-2R. The failure of anti-IL-2R to inhibit the activity of lamina propria-derived TCGF was not apparently owing to interference by soluble receptor with binding of monoclonal to target blast cells as no effect of supernatants on binding was observed. The results suggest that cells derived from the pig intestinal lamina propria fail to produce IL-2 following polyclonal activation in vitro. Consistent with this finding, IL-2 transcripts could be detected by polymerase chain reaction (PCR) following reverse transcription of mRNA derived from spleen and from mesenteric lymph node but not lamina propria lymphocytes, while IL-4 cDNA could be detected from all three sources.