T cell activation and the generation of effective immune responses is critically dependent on APC-derived signalling. The relative expression of B7 isoforms on APC may be important in determining the nature and extent of the immune response, and immunoregulatory cytokines may mediate their effects through alterations in B7 isoform expression. The effects of a panel of cytokines on B7 isoform expression on resting and activated monocytes and B cells was evaluated. IL10 and IL4, which induce the development of Th2 type T cells, downregulated expression of B7-2 and modestly upregulated expression of B7-1 on unstimulated human monocytes. IFN$\gamma,$ a potent inducer of Th1 type T cells, upregulated both B7-1 and B7-2 expression. TNF$\alpha$ downregulated B7-2 expression, but did not alter B7-1 expression. Addition of anti-IL10 antibodies did not abrogate the effects of TNF$\alpha$ on B7-2 expression. LPS had effects on B7 isoform expression on purified monocytes similar to those of IL10 in PBMC, namely marked B7-2 downregulation and modest B7-1 upregulation. None of the cytokines influenced the levels of expression of B7 isoforms on either resting or activated B cells. Thus cytokines that influence development of T helper type immune responses have differential effects on expression of individual B7 isoform on monocytes but not on B cells. These findings may have important implications in activation and control of immune responses in infections, autoimmunity and malignancies.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/10195 |
| Date | January 1996 |
| Creators | Creery, W. David. |
| Contributors | Diaz-Mitoma, F., |
| Publisher | University of Ottawa (Canada) |
| Source Sets | Université d’Ottawa |
| Detected Language | English |
| Type | Thesis |
| Format | 88 p. |
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