Activation of T cells from the intestinal lamina propria of the pig.
This study found CD4+ T cells present in leucocyte populations isolated from the lamina propria of the pig to be almost exclusively CD45RC-, consistent with their being highly differentiated by exposure to antigen. Following activation in vitro these cells up-regulated expression of IL-2R with similar kinetics to splenic CD4+ cells. However, while splenic cells progressively secreted IL-2 into cultures during the first 24 h, IL-2 was not detected in supernatants of lamina propria cells after 8 h. Reverse-transcriptase polymerase chain reaction (RT-PCR) confirmed that this reflected a transcriptional difference: IL-2 transcripts were detected in cultures of splenic and lamina propria cells in the first few hours after activation but persisted only in splenic cells. In contrast, IL-4 transcripts were strongly expressed by activated lamina propria cells. Cell-cycle analysis demonstrated that fewer lamina propria CD4+ cells progressed into S-phase than did splenic CD4+ cells (26.0 11.1% and 45.0 11.3% respectively, P=0.011). Our results suggest that CD4+ T cells in these populations are differentiated effector cells whose potential for expansion may be dependent upon local factors. Such cells may be targets for immunoregulation by their local microenvironment.
Department of Clinical Veterinary Sciences, University of Bristol, UK.
M
M
Bailey
F
F
Plunkett
A
A
Clarke
D
D
Sturgess
K
K
Haverson
C
C
Stokes
D000818:Animals; D002478:Cells, Cultured; D007376:Interleukin-2 / Q000032:analysis / Q000235:genetics; D007413:Intestinal Mucosa / Q000276:immunology*; D017493:Leukocyte Common Antigens / Q000378:metabolism*; D008213:Lymphocyte Activation; D016133:Polymerase Chain Reaction / Q000379:methods; D012333:RNA, Messenger / Q000032:analysis; D016196:S Phase; D013154:Spleen / Q000166:cytology; D013552:Swine / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D013997:Time Factors
D007376:Interleukin-2; D012333:RNA, Messenger; D017493:Leukocyte Common Antigens