Abstract
Abstract: :
Purpose:We have developed a system in which Th lymphocytes sensitized against hen egg lysozyme (HEL) induce ocular inflammation when adoptively transferred into recipients expressing HEL in their eyes (Kim, S.J. et al., IOVS, 2002). Only activated cells produce disease and Th type 1 (Th1) cells are superior to Th2 cells in their inflammation-inducing capacity. This study analyzed surface markers that characterize disease-inducing cells and tested the suppressive effect of pertussis toxin (PTX), an inhibitor of chemokine activity, on disease induction by polarized Th1 and Th2 cells. Methods:Th cells expressing a HEL-specific T cell receptor were polarized in vitro by activation with HEL in the presence of type-specific cytokines and antibodies against the opposite type. Naive Th lymphocytes and polarized Th1 and Th2 cells were analyzed by conventional flow cytometry for expression of various cell surface markers. The effect of PTX on disease induction was tested by administration of the toxin to recipient mice concurrently with the adoptive transfer of cells. Disease levels were assessed histologically. Results:Major observations of the flow cytometric analysis include: (1) Activation of CD4 cells profoundly increased expression of CD25 and CD69 on both Th1 and Th2 cells, but reduced the expression of CD62L (L-selectin), in particular on Th2 cells. In addition, the activation elevated moderately the expression of CD49d (integrin alpha-4, or VLA-4) and of CD54 (ICAM-1) on both Th cell types. (2) Th1 cells differed from Th2 cells in their selective expression of the chemokine receptor CXCR3. (3) Treatment of recipient mice with PTX effectively inhibited disease induction by both Th1 and Th2 cells, in particular when lower levels of disease were induced: the toxin effect decreased when severe levels of inflammation were induced. Conclusion:The profound differences between naive and activated cells in their expression of surface molecules is in line with the acquisition of disease-inducing capacity during activation. The difference between the pathogenic capacity of Th1 and Th2 cells could be attributed in part to differences in their surface molecule expression. The inhibitory effect of PTX suggests that chemokines are involved in pathogenic processes mediated by both Th cell types.
Keywords: 413 flow cytometry • 437 inflammation • 612 uveitis-clinical/animal model