Ki-1 (CD30) antigen is released by Ki-1-positive tumor cells in vitro and in vivo. I. Partial characterization of soluble Ki-1 antigen and detection of the antigen in cell culture supernatants and in serum by an enzyme-linked immunosorbent assay
✍ Scribed by Olivera Josimovic-Alasevic; Horst Dürkop; Roland Schwarting; Eva Backé; Harald Stein; Tibor Diamantstein
- Publisher
- John Wiley and Sons
- Year
- 1989
- Tongue
- English
- Weight
- 626 KB
- Volume
- 19
- Category
- Article
- ISSN
- 0014-2980
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✦ Synopsis
Ki-1 (CD30) antigen is released by Ki-l-positive tumor cells in vitro and in vivo I. Partial characterization of soluble Ki-1 antigen and detection of the antigen in cell culture supernatants and in serum by an enzyme-linked immunosorbent assay* An enzyme-linked immunosorbent assay (ELISA) has been developed that allows the quantitative determination of the Ki-1 (CD30) antigen in soluble form. Similar levels of sensitivity of this new Ki-1 ELISA and the ELISA previously described for measuring the soluble 55-kDa chain of the interleukin 2 receptor were seen. As assessed with this ELISA, the investigated Ki-1' permanent cell lines released the Ki-1 antigen into the culture supernatant. In culture supernatants of concanavalin A-activated human peripheral blood lymphocytes, however, this antigen could not be detected. The released Ki-1 antigen has an apparent molecular weight (M,) of 85 000, whereas the cell-associated Ki-1 antigen has an M, of 105000. We investigated sera from 30 normal donors, 15 patients with systemic infections, and 63 patients suffering from lymphomas for soluble Ki-1 antigen. In all sera from normal donors and patients with systemic infectious diseases, soluble Ki-1 antigen was below the detection limit (i.e., < 70 pg). In contrast, high amounts of the soluble Ki-1 antigen were found in sera from 18 malignant lymphomas containing Ki-1' tumor cells. This finding demonstrates that the release of the Ki-1 antigen takes place not only in vitro, but in vivo as well. Moreover, these results imply that the Ki-1 antigen may be used as a serum tumor marker.