Fig 1: Multiple influenza antigen modalities induce GC reactions and specific antibody secretion in human tonsil organoids(A) Experimental design and workflow for tonsil organoids. Cells and supernatants were assessed using multiple readouts to define immune signatures. Created with Biorender.com.(B and C) Representative flow cytometry staining (B) and summary data (C) for total B cell (CD45+CD19+CD3-) phenotypes from day 14 organoids stimulated with different influenza Ag modalities.(D) Representative flow cytometry staining of HA+ (red) and nonspecific (gray) B cells from day 14 organoids. Numbers indicate frequency of HA+ B cells of a given phenotype out of total HA+ B cells.(E) HA+ B cell frequencies.(F) HA+ plasmablast frequencies.(G) Quantification of HA-specific antibodies in day 14 organoid culture supernatants.(H) Virus neutralization by day 14 organoid culture supernatants; neutralization quantification by area under the curve (AUC).(I) Frequency of activated CXCR5+CD4 T cells and activated CD8 T cells on day 7. Activation was defined by dual expression of CD38 and HLA-DR. n = 12 donors (one experiment) for all data shown. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 using a Kruskal-Wallis test followed by paired Mann-Whitney U tests to compare groups. p values shown are for comparisons against the unstimulated control unless otherwise indicated by lines. Boxplots show the median, with hinges indicating the first and third quartiles and whiskers indicating the highest and lowest value within 1.5 times the interquartile range of the hinges. See also Tables 1 and S5 and Figures S1 and S2.