Tumor therapy with epidermal growth factor receptor vaccine investigated.

2003 MAY 7 - (NewsRx.com & NewsRx.net) -- Immunogene therapy of tumors was investigated with a vaccine based on xenogeneic epidermal growth factor receptor.

"The breaking of immune tolerance against self epidermal growth factor receptor (EGFr) should be a useful approach for the treatment of receptor-positive tumors with active immunization. To test this concept, we constructed a plasmid DNA encoding extracellular domain of xenogeneic (human) EGFr (hEe-p) or corresponding control mouse EGFr (mEe-p) and empty vector (c-p)," scientists in the People's Republic of China report.

"Mice immunized with hEe-p showed both protective and therapeutic antitumor activity against EGFr-positive tumor," wrote You Lu and colleagues at Sichuan University. "Sera isolated from the hEe-p-immunized mice exhibited positive staining for EGFr-positive tumor cells in flow cytometric analysis and recognized a single 170-kDa band in Western blot analysis. Ig subclasses responded to rEGFr proteins were elevated in IgG1, Ig2a, and Ig2b. There was the deposition of IgG on the tumor cells. Adoptive transfer of the purified Igs showed the antitumor activity."

The investigators found, "The increased killing activity of CTL against EGFr-positive tumor cells could be blocked by anti-CD8 or anti-MHC class I mAb. In vivo depletion of CD4+ T lymphocytes could completely abrogate the antitumor activity, whereas the ...