Characterization of New Breast Tumor-Specific Antigens Using a Novel Antigen Discovery System
Annual rept. 1 Jun 1998-31 May 1999
PITTSBURGH UNIV PA
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We have devised a novel tumor antigen discovery system that utilizes dendritic cells DCs as antigen presenting cells to prime naive T cells against peptides and proteins isolated from an epithelial tumor MS that does not express the known breast tumor-specific antigens, MUC-1 and Her-2neu. We have extracted peptides from the HLA Class I molecules of the tumor, fractionated the peptides by reverse-phase HPLC RP-HPLC, and loaded onto DCs to prime naive CD8 T cells. Our results showed that 12 of the 65 individual CD8 T cell cultures recognized the original tumor. Further analysis of the positive fractions by electrospray mass spectrometry yielded 8 peptide candidates. We are in the process of acquiring the amino acid sequences of these peptides. We have also fractionated protein extracts of the tumor by RP-HPLC and loaded onto DCs to prime naive CD4 T cells. Our first attempt yielded an immunostimulatory fraction that contained predominantly two proteins of 17 kD and 19 kD. We have repeated this process, and our results showed 12 of the 52 individual CD4 T cell cultures recognized the original tumor. We are in the process of characterizing the identity of these positive protein fractions.
- Genetic Engineering and Molecular Biology
- Medicine and Medical Research