ENHANCEMENT OF CYTOLYTIC T-LYMPHOCYTE PRECURSOR FREQUENCY IN MELANOMAPATIENTS FOLLOWING IMMUNIZATION WITH THE MAGE-1 PEPTIDE LOADED ANTIGEN-PRESENTING CELL-BASED VACCINE

Identification of human melanoma-associated peptide antigens for CTLs has opened unprecedented opportunities for active specific immunothera py for melanoma with synthetic peptide, We have shown that immunizatio n with a MAGE-1 gene encoded nonapeptide (EADPTGHSY)-pulsed autologous antigen presenting cell-based vaccine induces autologous melanoma-rea ctive and peptide-specific CTL response, in situ, at the vaccination s ite and at distant tumor deposits in patients who are HLA-A1+ and whos e melanoma cells express the MAGE-1 mRNA, Here, we show that such immu nization is also capable of increasing the frequency of autologous mel anoma-reactive CTL precursors in the circulation, We further show that in vitro stimulation of the postimmunization peripheral blood lymphoc ytes with the MAGE-1 nonapeptide-loaded antigen presenting cell and in terleukin-2 leads to significant expansion of peptide-specific and aut ologous melanoma-reactive CTL response.