Increase of the immunostimulatory effect of dendritic cells by pulsing with CA 19-9 protein

Previously, a relative resistance of solid tumor cells to immunologic effec tor cells was shown in vitro. This resistance could be one reason for the c linical phenomenon of resistance of patients with colon carcinoma or other solid tumors to immunologic therapeutic approaches, In this study, dendriti c cells (DCs) pulsed with CA 19-9 protein were rested for their immunostimu latory capacity of immunologic effector cells against cells derived from co lon and pancreatic carcinoma. Dendritic cell cultures coexpressed CMRF-44 a nd CD1a, markers typical of DCs, in 31.5% +/- 5.3% after 13 days of culture . Coculture of NK-like T lymphocytes with DCs led to a significant increase in cytotoxic activity, as measured using a lactate dehydrogenase release a ssay. Cytotoxic activity could be further increased using DCs pulsed with C A 19-9 protein. The effect of CA 19-9 on increasing the cytotoxic effect of NK-like T lymphocytes was dose dependent. Similarly, cocultivation of DCs with NK-like T cells derived from patients with metastatic pancreatic cance r and elevated CA 19-9 serum levels led to a significant increase in cytoto xic activity. In conclusion, DCs pulsed with CA 19-9 protein can increase t he cytotoxic activity of immunologic effector cells against colon carcinoma and pancreatic cancer cells, Dendritic cells pulsed with CA 19-9 protein m ay have an important effect on immunotherapeutic protocols for patients wit h cancer.