Irradiation of genetically modified plasmacytoma vaccines results in upregulation of CD80, molecule expression, IL-2 production and higher therapeutic efficacy of the vaccines

It has been found previously that irradiated, IL-2 gene-modified plasmacyto ma (X63-m-IL-2) vaccines are more efficient in the therapy of the parental (X63-Ag8.653) plasmacytoma than live plasmacytoma vaccines. In this communi cation, we have demonstrated that irradiation of murine IL-2-producing plas macytoma vaccines resulted in upregulation of CD80 molecule expression and IL-2 production. The expression of MHC class I antigens was not altered. Th e upregulation of the CD80 membrane molecule expression in X63-m-IL-2 cells was higher after irradiation with 150 Gy than after irradiation with 50 Gy , Comparable upregulation of the CD80 molecule expression has also been dem onstrated after irradiation of the parental murine X63-Ag8.653 plasmacytoma cells. The results indicate that upregulation of the CD80 molecule express ion and enhanced IL-2 production in irradiated X63-m-IL-2 cells was respons ible for the higher therapeutic effectiveness of the irradiated plasmacytom a vaccine.