Lymphocyte activation and trafficking are indispensable to the immune system. CD44, an adhesion molecule, plays important roles in T cell activation, lymphocyte homing/trafficking, and tumor metastasis. Although the functions of CD44 have been shown in T cells and other leukocytes, little is known about its role in B cells. The effects of CD44 cross-linking on murine B cell activation via CD40L/IL-4 was explored using the anti-CD44 mAbs RK3G9 and IM7. Immobilized RK3G9 and IM7 could strongly inhibit B cell proliferation and Ig production, with IgE inhibition being prominent. Soluble anti-CD44 had no effect. The inhibitory effect of RK3G9 was not influenced by addition of anti-FCγRII, indicating no role for the inhibitory receptor. The effects of delayed addition of immobilized anti-CD44 mAbs were studied, and the results indicated no inhibition after 96 hrs of culture. B cells were also activated by either LPS or anti-IgM F(ab')2. While LPS-induced B cell activation was inhibited by immobilized anti-CD44 mAbs, anti-IgM activation was refractory. Interestingly, addition of both anti-IgM and CD40L or LPS resulted in some modulation of the inhibitory activity. Additionally, FACS and Elispot revealed that RK3G9-treated cells had reduced numbers of plasma cells. Taken together, these results suggest that CD44 cross-linking could control polyclonal B cell activation by CD40L, but allow sIgM/CD40L activation to continue.
| Identifer | oai:union.ndltd.org:vcu.edu/oai:scholarscompass.vcu.edu:etd-2003 |
| Date | 01 January 2006 |
| Creators | Wyant, Tiana L. |
| Publisher | VCU Scholars Compass |
| Source Sets | Virginia Commonwealth University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
| Rights | © The Author |
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