Abstract
Follicular helper CD4 T (Tfh) cells play an essential role in the formation of germinal centers (GCs), where mature B cells proliferate, differentiate, and provide long-term protective humoral responses. Despite the extensive phenotypic characterization and identification of human Tfh cell subsets, their spatial positioning at tissue level is not well understood. Here, we describe a quantitative multiplexed immunofluorescence approach allowing for the comprehensive in situ characterization of Tfh cells in human tonsils and lymph nodes (LNs) from individuals with angioimmunoblastic T-cell lymphoma (AITL). We have developed eight multiplexed panels comprising a spectrum of Tfh cell markers, like PD-1, CXCR5, and ICOS, along with transcription factors (Bcl6, Tbet, GATA3), to assess their expression, frequencies, spatial distribution and co-localization in a quantitative manner. Combined analysis of relevant markers revealed the presence of several Tfh cell subsets at tissue level based on the differential expression of surface receptors, nuclear factors as well as their distinct localization within the follicular areas. Interestingly, we found a considerable amount of tonsillar Tfh cells expressing high levels of the Th2 regulator GATA3. The co-expression of GATA3, CXCR5, and BCL6, points to an important role of GATA3 for the generation of effector human Tfh cells. Furthermore, our data revealed significantly different Tfh cell profile signatures between health and disease. Therefore, our imaging platform generates meaningful information for the in situ characterization of human Tfh cells and could provide the base for future studies aiming to a comprehensive understanding of Tfh cell tissue heterogeneity.
Highlights
Tfh cells is a highly specialized subset of CD4+ T cells playing a critical role in protective immunity by helping B cells to produce antibodies against foreign pathogens
High expression of PD-1, a widely used marker for Tfh cell identification, was exclusively found in germinal centers (GCs) CD4 T cells with approximately 75% of them characterized by a PD-1+ phenotype
Published data regarding the expression of CXCR5 in lymphoid tissues and blood have been essentially derived from flow cytometry analyses and frozen section immunohistochemistry [71, 72], which have consistently shown high levels of expression in Tfh cells the GC ones
Summary
Tfh cells is a highly specialized subset of CD4+ T cells playing a critical role in protective immunity by helping B cells to produce antibodies against foreign pathogens. They are located in secondary lymphoid organs (SLOs), including tonsil, spleen and lymph nodes. These organs accommodate numerous lymphocytes, organized in T- and B-cell zones with Tfh cells found exclusively in the B-cell zone [1]. By controlling the mutation diversity of GC B cells, the strength of the delivered Tfh help is a critical factor for the excessive somatic hypermutation required for the development of broadly neutralizing antibodies [17]. The lineage association between the GC- and cTfh cells is not clear, analysis of cTfh dynamics has been successfully used as a surrogate of GC reactivity under certain circumstances [19]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
