Spermine-directed immunosuppression of cervical carcinoma cell sensitivity to a majority of lymphokine-activated killer lymphocyte cytotoxicity.

The polyamine spermine, naturally present at millimolar levels in seminal plasma, inhibits proliferation of natural killer cells and T lymphocytes, directly binds to DNA and alters cervical cell ploidy indicating its potential ++contribution to the etiology of cervical cancer and its possible role in suppression of the destruction of dysplastic and neoplastic cervical epithelial cells by cytotoxic lymphocytes. This study demonstrates that spermine suppresses sensitivity of cervical carcinoma cells to lymphokine-activated killer (LAK) lymphocytes from more than half of normal individuals. Direct treatment of 51Cr-labelled QGU cervical carcinoma cells with < or = 10-11 M spermine for 1 h reduces cytotoxic destruction of QGU cells by human LAK lymphocytes up to 60% (p < or = 0.05) as shown by decreased LAK lymphocyte lytic units 20%. Cervical carcinoma cells are inherently very sensitive to LAK lymphocytes and spermine may be an important immunosuppressive agent in natural immunity against cervical cancer.