Immunological effects of human tonsil organoids after influenza virus infection

Abstract

Objective To establish a human tonsil organoid model and investigate the immunological effects of this tonsil organoid infected by influenza virus. Methods Human tonsil tissue removed by adenoid hypertrophy surgery were subjected to gradient centrifugation, and then the obtain cells were cultured in vitro with using a 2.5D-Transwell chamber in combination with IL-2 and B cell activating factor (Baff) to construct a human tonsil organoid. Single cell transcriptome sequencing (scRNA-seq) was used to analyze the distribution of influenza virus receptors in different cell subsets of the tonsil organoid. Immunofluorescence assay and flow cytometry were applied to detect the immunological effects of the tonsil organoid in 48 h after influenza virus infection. Results The tonsil organoids were established successfully using this 2.5D-Transwell culture technique. scRNA-seq analysis showed that the receptors for influenza virus were extensively distributed in nearly all of cell subsets of tonsil organoids. In 48 h after influenza virus infection, the tonsil organoids could generate a large amount of plasma cells and memory B cells to produce specific IgG antibodies. In addition, direct infection of the virus promoted the production of TNF-α and IL-2 from CD8+ T cells and the secretion of TNF-α, IFN-γ and IL-2 by CD4+ T cells. Conclusion The tonsil organoids can be established successfully and reach maturity at about the 6th day after culture. The receptors for influenza virus are widely distributed in human tonsil organoids. Influenza virus directly infects human T cells, leading to T cell activation and cytokine releasing. Moreover, influenza virus infection also promotes B cells differentiate into plasma cells and induce the secretion of IgG as well as the formation of memory B cells.

Keywords

• human tonsil organoid
• adaptive immune response
• immune memory
• inflammatory factors
• plasma cells