Head and neck squamous cell carcinoma(HNSCC) has been associated with host immunosuppression, including depressed T-lymphocyte and natural killer cell function. This immunosuppression has been shown to be most pronounced in the locoregional environment of the tumor and appears to be mediated by soluble suppressor factor prostaglandinE₂(PGE₂). PGE₂ is a product of cell membrane phospholipid metabolism that is known to have potent immunoregulatory activity including inhibition of natural killer cell activity and antibody dependent cell mediated cytotoxicity(ADCC).

In our experiment, we have established an ADCC assay with IgGl cMAB SF-25, 323A/3 using human squamous cell carcinoma of the head and neck cell line(PCI-50) as target. The measurement of cytotoxicity was determined by measuring the release of ⁵¹Chromium from the target cells after 4 hour incubation.

PGE₂ inhibited antibody dependant cell mediated cytotoxicity.

It thus implies that the production of prostaglandins by tumor cells may constitute a means by which the tumor cells subvert the effect of a cellular immune response that is directed against them and arming of NK cells with chimeric antibody could be considered in developing means for treatment of human SCCHN in adjuvant setting.