Efficient, safe and functional CD40LG correction of human HIGM1 T cells by "One-size-fits-all" conditional correction strategy.Figure 1A, B Schematics of (A) gene editing strategy and donor DNA template for intron 1 CD40LG target locus and (B) experimental protocol in T cells. C Representative plot showing gating strategy for CD4+ T cell phenotypes. Effector Memory RA (TEMRA): CD45RA+ CD62L-; Effector Memory (EM): CD45RA-CD62L-; Central Memory (CM): CD45RA-CD62L+; Stem Cell Memory (TSCM): CD45RA+ CD62L+. D Percentage of GFP+ cells within T cell subpopulations 17 days after CD40LG editing of healthy male donor (HD; n=11) or patient (Pt; n=1) derived CD4+ T cells, measured by FACS analysis. Median ± IQR. E Percentage of GFP+ cells or HDR in T cells from (D). Median ± IQR. F Population composition in male HD or patient derived untreated (n=9 HD UT, 1 Pt UT) or bulk edited T cells (Treat) from (D). For each subpopulation, the comparisons between HD Treated vs UT were performed by using LME models, with random effects defined to account for the same donor and for different number of replicates per donor within group. All p-values were adjusted with Bonferroni's correction to account for multiple testing. In all LME models, the percentages were used in square root scale to meet the assumption of normality of the residuals of the model. Mean ± SEM. G Percentage of TCRBV families detected by spectratyping. UT, sorted edited (GFP+), sorted non-edited (GFP-) CD4+ T cells derived from male HD (n=1) or patient (Pt; n=1) were analyzed at 17 days after CD40LG editing. H Time course of CD40L surface expression after PMA/Ionomycin stimulation measured by Relative Fluorescence Intensity (RFI, normalized to T0; left) and percentage (right) on UT (n=3), edited (GFP+) or unedited (GFP-) HD or Pt CD4+ T cells from (D) (n=9 HD, 1 Pt). Longitudinal comparisons between HD GFP+ vs GFP- were performed with an LME model, accounting for multiple donors and separately for RFI and %CD40L+ cells (see Appendix Supplementary Statistical Methods). The reported statistical comparisons refer only to 8 hours time-point (****p<0.0001 and *p=0.0450, respectively). #measured on the small fraction of CD40L+ cells. Median ± IQR. I Representative plots showing CD40L and GFP expression in UT or bulk edited (Tretated) CD4+ T cells derived from male HD or Pt from (D) at 8 hr after PMA/Ionomycin stimulation. J Cartoon depicting protocol of B-T cell co-culture used to assess functionality of corrected T cells. CD4+ T cells were stimulated with beads (B) or with PMA/Ionomycin (PI) or kept resting (R) prior to co-culture with allogeneic naive B cells (1:1 ratio). B cells cultured alone or in presence of soluble CD40L (sCD40L) were used as negative and positive controls, respectively. K Left: IgG positive spots resulting from B-T cell co-culture. Right: IgG+ secreting B cells, evaluated by ELISPOT assay. B cells were isolated from PB of HD and co-cultured with male HD or Pt sorted GFP+, GFP- and UT T cells, resting (R) or stimulated with beads (B) or PMA/Ionomycin (PI). B cells cultured alone (-) or in presence of sCD40L (+) were used as negative and positive controls, respectively (n=1 for each group). L Left: Histograms representing proliferation results from B-T cell co-culture. Right: Analysis of B cell proliferative capacity by Cell Trace dilution assay in allogeneic sorted B cells isolated from PB of HD and co-cultured with HD or Pt T cells from (K). B cells cultured alone (-) or in presence of sCD40L (+) were used as negative and positive controls, respectively (n=2 for each group). Mean ± SEM.