Efficient induction of cytotoxic CD8+ T cells against exogenous proteins: establishment and characterization of a T cell line specific for the membrane protein ActA of Listeria monocytogenes |
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Authors: | Dunja Bruder,Ayub Darji,Dmitry M. Gakamsky,Trinad Chakraborty,Israel Pecht,Jü rgen Wehland,Siegfried Weiss |
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Abstract: | The property of listeriolysin (LLO) to introduce soluble passenger proteins into the cytosol of antigen-presenting cells allows the induction of CD8+ cytotoxic T cells against such antigens. To overcome the potential problem of presentation of the immunodominant epitope LLO91-99 by H-2Kd, a variant LLO92A was established in which Tyr 92 was replaced by Ala. Immunization of BALB/c mice with purified LLO92A failed to stimulate cytotoxic T cells specific for either the epitope LLO91-99 or for any other LLO-derived peptide. Injection of mixtures of purified LLO92A and soluble nucleoprotein (NP) of influenza virus into mice resulted in a strong cytotoxic T cell response exclusively directed against NP. The LLO92A variant was successfully used to generate, propagate and characterize a CD8+ T cell line specific for the membrane-bound virulence factor ActA of Listeria monocytogenes. Interestingly, wild-type ActA bound to the surface of live L. monocytogenes was not presented by MHC class I molecules to the CD8+ T cell line. |
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Keywords: | Listeria monocytogenes Membrane protein ActA Cytotoxic T cell Mutant listerioly sin Soluble antigen |
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