(The FASEB Journal. 2008;22:676.1)
© 2008 FASEB
(The FASEB Journal. 2008;22:676.1.)
© 2008 FASEB
A high-throughput genetic system for identifying enhanced altered peptide ligands of tumor associated antigens: implications for enhancing adoptive immunotherapy
C. Siddiq Abdul-Alim,
Yongqing Li and
Cassian Yee
Immunology, Fred Hutchinson Cancer Research Center, Seattle, WA
ABSTRACT
Cancer immunotherapy offers a promising approach for eradicating metastatic tumors that fail to fully respond to existing therapies. Unfortunately, efforts are frequently hampered by tolerance mechanisms that act to prevent autoimmunity. A potential means for circumventing these mechanisms is the use of altered peptide ligands (APL). APLs are mutant T cell epitopes that can either enhance or dampen a T cell response. Existing methods for identifying effective APLs are either limited in scope or are expensive and technically restrictive. The objective of this study is to develop a comprehensive genetic approach for identifying enhanced APLs of CTL epitopes. With this procedure every point mutant of a CTL epitope can be generated and screened, and the effective APL easily identified. In this study we utilize saturation mutagenesis to independently mutagenize every codon of Mart-126–35 A27L. Recombinant mini-gene products of the APLs are cross-presented to Mart-126–35 -specific CTL clones via dendritic cells in a 96-well based assay format. Here we identify three novel superagonist peptides of Mart-126–35, which can generate higher frequencies of Mart-126–35 -specific CTL from peripheral blood leukocytes of melanoma patients. This work has implications for the identification of APLs that may prove clinically beneficial in generating tumor-specific CTLs for use in adoptive T cell immunotherapy.
