Preparation of a diagnostic antigen of human melanoma based on lymphocyte activation as measured by intracellular fluorescein fluorescence polarization

The intracellular fluorescein fluorescence polarization (IFFP) test indicat es that peripheral blood lymphocytes (PBL) of cancer patients display stimu latory sensitivity to a short incubation with specific tumor protein extrac ts. Ln this work, a human lymphocyte activation melanoma antigen (LAMA) was purified from supernatant of a human melanoma cell line (L1M1), which coul d specifically stimulate lymphocytes of melanoma patients. The results show ed a significant stimulation of lymphocytes from healthy donors after incub ation with phytohaemagglutinin (PHA), while no stimulation was observed aft er incubation with LAMA. On the other hand, lymphocytes from melanoma patie nts showed a significant stimulation with LAMA, while generally showing min or or no stimulation with PHA. Melanoma specificity of LAMA was demonstrate d by no response in lymphocytes from patients of lung, colon, or breast can cer. The purified fraction is therefore considered to be a shared tissue-sp ecific antigen which may be useful in immunodiagnosis and immunotherapy of melanoma.