Transient expression of bacterial gene fragments in eukaryotic cells: implications for CD8+ T cell epitope analysis

CD8(+) T cells are potent effecters of acquired immunity against some virus es and intracellular bacterial pathogens. Antigens recognized by CD8(+) T c ells are small, 8-9 amino acid peptides derived from proteins produced by t he pathogen. These peptides are presented by MHC class I molecules on the s urface of the infected cell. When characterizing the CD8(+) T cell response to a bacterial or viral pathogen, it is often necessary to express an anti genic protein in a eukaryotic host cell that is capable of processing and p resenting peptide epitopes to antigen-specific CD8(+) T cells. We describe a system designed to transiently express bacterial polypeptides and MHC cla ss I molecules in eukaryotic cells. Recognition of these peptide-MHC comple xes stimulates TNF production by antigen-specific CD8(+) T cell lines. This system should be useful for analysis of CD8(+) T cell epitope-containing b acterial gene fragments when expression of the entire bacterial protein is detrimental to the eukaryotic cell, or when overexpression of the bacterial gene is detrimental to the bacterial cloning strain. Furthermore, this sys tem can be used for the rapid mapping of CD8(+) T cell epitopes within a pr otein. (C) 2000 Elsevier Science B.V. All rights reserved.