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.
Bailey
M
M
Department of Clinical Veterinary Sciences, University of Bristol, UK.
Plunkett
F
F
Clarke
A
A
Sturgess
D
D
Haverson
K
K
Stokes
C
C
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