Fig. 7: Enhanced TCF-1 expression rectifies defective T_FH differentiation in METTL3-null cell.

a Scheme of TCF-1 rescue experiment. SMARTA cells were transduced with TCF-1 structure (full-length CDS of P45 isoform without 3′ UTR region) by using a retrovirus transduction system. Then, the transduced cells were adoptively transferred into congenic CD45.1⁺ wild-type mice followed by LCMV-Armstrong infection, and analyzed on day 8 post viral infection. b Flow cytometry analysis of TCF-1 gMFI in SMARTA GFP⁺CD4⁺ cells from recipient mice on 8 dpi. Quantitation of TCF-1 gMFI is shown on the right (n = 3 per group). c, d Flow cytometry analysis of CD44⁺CXCR5⁺ T_FH populations and CD44⁺CXCR5^– T_H1 subsets gated on SMARTA GFP⁺CD4⁺ T cells from different host mice adoptively transferred with empty vector (EV) or TCF-1 retrovirus-introduced SMARTA cells at 8 days post infection. Summary of the frequency and cell numbers of T_FH cells and T_H1 cells are shown in d (n = 3 per group). e, f Flow cytometry analysis of PD-1^hiCXCR5⁺ GC T_FH populations gated on SMARTA GFP⁺CD4⁺ T cells from different host mice adoptively transferred with EV or TCF-1 retrovirus-introduced SMARTA cells. Summary of the frequency and cell numbers of GC T_FH cells are shown in f (n = 3 per group). g, h Flow cytometry analysis of gMFIs of TCF-1, CXCR5, PD-1, ICOS, and Bcl-6 on CD44⁺CXCR5⁺ T_FH cells transduced with EV or TCF-1 retrovirus. Quantification of the gMFIs is shown in h (n = 3 per group). Data are representative of three independent experiments. Error bars indicate standard error of the mean. P value was calculated by one-way ANOVA, followed by unpaired two-tailed Student’s t test for indicated pairwise comparisons.