| First Author | Schrader CE | Year | 1997 |
| Journal | J Immunol | Volume | 158 |
| Issue | 1 | Pages | 153-62 |
| PubMed ID | 8977186 | Mgi Jnum | J:37219 |
| Mgi Id | MGI:84621 | Doi | 10.4049/jimmunol.158.1.153 |
| Citation | Schrader CE, et al. (1997) Cognate T cell help for CD40-deficient B cells induces c-myc RNA expression, but DNA synthesis requires an additional signal through surface Ig. J Immunol 158(1):153-62 |
| abstractText | To investigate the role of CD40 ligand in the delivery of help to B cells, we examined the Ag-specific interaction of B cells from CD40-deficient mice with a Th2 cell line in vitro. Small resting B cells from normal mice are stimulated to synthesize DNA when they present monovalent Ag (rabbit Fab anti-Ig) to a rabbit Ig-specific Th cell line. This response, which is independent of a signal through the B cell Ag receptor (sIg), is nearly absent in B cells from CD40-deficient mice. The CD40-deficient B cells are not defective in Ag presentation because they induce T cell IL-4 synthesis as well as normal B cells. Also, CD40-deficient B cells respond to T cell help with DNA synthesis almost as well as normal B cells if an additional signal is provided through sIg. In conjunction with a sIg signal, cell contact with helper T cells induces DNA synthesis more effectively than soluble cytokines. CD40-independent T cell help can also be measured as an early increase in c-myc mRNA levels in CD40-deficient B cells presenting Ag to helper T cells, although the levels of c-myc RNA expression are lower than those in normal B cells. However, c-myc RNA induced by noncognate interaction with anti-CD3-activated T cells is completely CD40 dependent. We conclude that early growth signals from activated Th cells are received by CD40-/- B cells, but that CD40 and/or sIg signals are required for efficient induction of DNA synthesis. |
