CONTACTS
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| Phone: (706) 721-8739 |
| Email: lignatowicz@mail.mcg.edu |
| Room: CA4124 |
| Address: |
| Medical College of Georgia, |
| CBGM, 1120 15th Street, |
| CA4124, |
| Augusta, GA 30912 |
| MCG Faculty Page |
EDUCATION
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| Ph.D., Immunology |
| Institute of Immunology and Experimental Therapy, Wroclaw, Poland |
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| M.Sc., Biochemistry and Molecular Biology |
| Department of. Biochemistry and Molecular Biology, Wroclaw University, Poland |
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| B.Sc., Biochemistry and Molecular Biology |
| Department of Biochemistry and Molecular Biology, Wroclaw University, Poland |
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LESZEK IGNATOWIZ:
ASSOCIATE PROFESSOR
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Research Area
Research in my laboratory is focused on studying the ontogeny and function of T lymphocytes using genetically manipulated mice. T lymphocytes express antigen receptors (also called T cell receptors-TCRs) that recognize antigens as short peptides bound to MHC. These peptides are derived from the body’s self-proteins or outside sources. In healthy individuals, T cells remain unresponsive (tolerant) to self-peptides/MHC complexes. Tolerance to self is enforced in the thymus, where developing thymocytes with high avidity TCRs against self MHC/peptide complexes are negatively selected. Thymocytes that survive selection express TCRs that weakly recognize self-peptide/MHC complexes on thymic stromal cells. An important feature of T cell development that remains to be explained is how self-peptide/MHC complexes can deliver both death-inducing signals that purge the repertoire of potentially harmful self-reactive T cells and positive signals that ensure survival but not overt activation.
To determine how T lymphocytes with auto-aggressive specificities escape death in the thymus, we have studied mice that express transgenic MHC molecules bound with single, covalently attached peptide, instead of thousands of peptides that are naturally bound to MHC. The TCR repertoire in “single peptide” mice is not depleted of potentially autoreactive T cells that are found in peripheral lymphoid organs. Nevertheless, mice remain healthy because T cells selected in the thymus by one type of MHC/peptide complex are also only exposed to the same complexes in the rest of the body. However, when these mice receive cells from wild-type mice expressing the same MHC bound with many self-peptides, it elicits a robust T cells activation of T cells. These mice are therefore a valuable model to study how the lack of central tolerance provokes systemic and organ-specific autoimmunity.
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