Accumulating evidence has shown that immunoglobulin (Ig) is unexpectedly expressed by epithelial cancer cells and that it can promote tumor growth. The main purpose of this study was to explore the components of the cancerous Ig and its possible function. The presence of cancerous Ig in the Golgi apparatus was confirmed by immunofluorescence, indirectly suggesting that the cancerous Ig was processed and packaged in cancer cells. Western blot analysis and ELISA results indicated that cancer cells produced membrane Ig and secreted Ig into the supernatant fraction. The cancerous Ig consists of an Î ± heavy chain and a Î°light chain. Finally, by analyzing the Ig components pulled down by protein A beads, the cancerous Ig was found to be structurally distinct from normal Ig. The cancerous Ig was truncated or aberrant. Although the underlying mechanism that causes the abnormalities has not been determined, our current discoveries strengthen our previous findings and promise fruitful future explorations.
Bibliographical noteFunding Information:
This work was supported by the National High Technology Research and Development Program (863) of China (no. 2006AA02A404), the National Nature Science Foundation of China (nos. 30471968 and 30772465) and the CMB Educational Thrust Project (04-799).
- truncated immunoglobulin
- tumor immunology