title: The role of CD4(+) T cells in BKV-specific T cell immunity.
abstract: Reactivation of polyomavirus BK (BKV) infection represents a severe complication in kidney transplant (KTX) patients. We previously reported an association between a declining BK viral load and the reconstitution of CD4(+) T cell BKV-specific immunity in patients following kidney transplantation. However, the specific contribution of CD4(+) T cells in the regulation of BKV-replication is unknown. Nevertheless, in vitro enrichment of BKV-specific T cells and subsequent adoptive T cell transfer may improve the restoration of immune competence in KTX patients with BKV infection. To date, strategies to capture human BKV-specific T cells with the ensuing expansion to clinically useful numbers are lacking. Here, we demonstrated a comprehensive flow cytometric analysis of the BKV-specific T cell response that permits access to the majority of T cells specific for immunodominant BKV antigens. A full-spectrum evaluation of the BKV-specific T cell response was performed by stimulating peripheral blood mononuclear cells (PBMC) with a mixture of BKV immunodominant peptide pools at varying concentrations and measuring activation marker expression and cytokine secretion. We also examined the effects of co-stimulation and PBMC resting time prior to activation. We defined the narrow range of stimulation conditions that permit the capture and expansion of functional BKV-specific T cell lines. The generated BKV-specific T cell lines showed the highest specificity and functionality when the T cells were captured according to IFNγ-secretion. This study highlights the multifunctional and cytolytic BKV-specific CD4(+) T cells as a dominant population within the generated T cell product. This method offers a novel approach for the generation of BKV-specific T cell lines for adoptive immunotherapy and underscores the critical role of CD4(+) T cells in the clearance of BKV.
authors: Department of Nephrology, Charité University Medicine, Berlin, Germany.
authors: B J D
authors: BJ
authors: Weist
authors: M
authors: M
authors: Schmueck
authors: H
authors: H
authors: Fuehrer
authors: A
authors: A
authors: Sattler
authors: P
authors: P
authors: Reinke
authors: N
authors: N
authors: Babel
mesh_terms: D001739:BK Virus / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D003602:Cytotoxicity, Immunologic; D005434:Flow Cytometry; D006801:Humans; D016030:Kidney Transplantation; D027601:Polyomavirus Infections / Q000276:immunology* / Q000821:virology; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D066027:Transplant Recipients; D014412:Tumor Virus Infections / Q000276:immunology* / Q000821:virology