A high-sensitivity detection system for monitoring of rare antigen specific naïve and memory T helper cells (58.6)

Abstract

CD4+ T cells play a central role in the immune defense against pathogens or tumors but also in immunopathology, such as autoimmunity or allergy. However, due to technical limitations, comprehensive information about the frequency and phenotype of antigen-specific CD4+ T cells against many disease-relevant antigens is missing. In particular the nature of the human naïve repertoire is elusive. We have developed a new, sensitive detection system for antigen-specific T helper cells, based on a combination of magnetic pre-enrichment and multi-parametric flow cytometric analysis of CD154 (CD40L)-expressing CD4+ T cells upon in vitro activation with antigens. The high sensitivity of 1 cell out of 105 to 106 enables the direct enumeration of memory and naïve CD4+ T cells reactive against basically any recall or primary antigen. Importantly, our technology allowed us to rapidly analyze sufficient numbers of target cells to discriminate even small functional or phenotypic subpopulations within the total antigen-specific T cell pool, undetectable by conventional methods. We used this assay for a first characterization of tumor- and auto-antigen reactive CD4+ T cells from healthy subjects as well as for the in depth characterization of rare pathogen specific T cells. The possibility to visualize T cells reactive against any antigen of interest even in the naïve repertoire will open up new possibilities to advance human T cell research and to improve clinical diagnostics and prognosis.