PRIMARY HUMAN MESOTHELIOMA CELLS EXPRESS CLASS-II MHC, ICAM-1 AND B7-2 AND CAN PRESENT RECALL ANTIGENS TO AUTOLOGOUS BLOOD-LYMPHOCYTES

Mesothelioma cells (MMc) are considered to be weakly immunogenic and t he experimental approaches attempting to induce an immune response aga inst these cells have been disappointing, Our aim was to investigate w hether MMc possess the surface accessory molecules involved in antigen presentation and whether these cells are capable of presenting recall antigens to autologous blood lymphocytes. pour primary MMc cultures w ere generated from malignant effusions and examined to assess whether the accessory molecules required for antigen presentation were present on their surfaces, Intercellular adhesion molecule-1 (ICAM-1; CD54): class I and class II major histocompatibility complex-DR (MHCI and MHC II-DR); B7-1 (CD80.3); and B7-2 (CD86) expression by MMc was studied b y immunocytochemical and/or FACScan analysis. MMc were pulsed with pur ified protein derivative (PPD), Tetanus toroid (TT) and Candida albica ns (CA) bodies, and incubated with autologous lymphocytes, Lymphocyte proliferation was estimated by radionucleotide incorporation, Phenotyp ic analysis showed the presence of MHCII-DR, ICAM-1 and 87-2 on primar y MMc cultures, whereas the phenotypic evaluation of 2 established MMc lines did not show the presence of the B7-1 and B7-2 molecules. In ad dition, MHCII-DR was detectable only after interferon gamma (IFN-gamma ) stimulation. Primary MMc cultures acquired the capability to induce lymphocyte proliferation after pulse with the recall antigens, To achi eve characterization of these lymphocytes, we generated a PPD-specific CD4(+) T-cell clone. PPD-pulsed MMc were shown to specifically induce T-cell clone proliferation through a MHCII-DR-mediated process. We co nclude that primary MMc possess the surface molecules required for ant igen presentation and can present recall antigens to CD4(+) lymphocyte s, (C) 1998 Wiley-Liss, Inc.