Fig. 1: IgA–pIgR colocalization is associated with protective immunity in human ovarian cancer.

a, Left, percentage of FACS cell counts of IgA⁺, IgG⁺ or IgM⁺ cells among Ig⁺ B cells or plasmablasts or plasma cells, normalized to 10,000 viable CD45⁺ cells. B cells, CD45⁺CD3⁻CD19⁺CD20⁺ cells; plasmablasts, CD45⁺CD3⁻CD19⁺CD20⁻CD38^high cells; plasma cells, CD45⁺CD3⁻CD19⁺CD20⁻CD138⁺ and CD45⁺CD3⁻CD19⁻CD20⁻CD138⁺ cells. Each dot represents one tumour (n = 29). Details of box plots can be found in Methods. P values were obtained by a two-way analysis of variance (ANOVA) followed by Dunnett’s test for multiple comparisons. Supplementary Table 1 provides further details on statistics. Right, bar graphs representing the percentage of each isotype produced by plasma cells (top) or B cells (bottom) in the same tumours, normalized to 10,000 viable CD45⁺ cells. IC, intracellular. b, IgA-coated CD45⁻EpCAM⁺ tumour epithelial cells (mean ± s.e.m., n = 10) in dissociated HGSOC. c, Expression of pIgR protein in independent HGSOC (n = 27); tumour-free Fallopian tube (n = 3), ovary (n = 5) and omental (n = 4) samples; ovarian tumour cell lines; and K562 leukaemia cells and THP1 monocyte cells (negative controls). Positive control, recombinant human pIgR. Western blots were repeated twice. NSCLC, non-small-cell lung cancer. d, Histograms showing FACS analysis of pIgR, in ovarian surface epithelial (OSE), K562, THP1, wild-type or PIGR-ablated (pIgR^CRISPR) OVCAR3 cells. e, Left, representative (n = 273) combined staining of IgA, pIgR, IgG, PCK and DAPI. Instances with IgA–pIgR colocalization are indicated with arrows. Scale bar, 50 μm (top left), 20 μm (all other panels). Top right, representative (n = 137, IgA–pIgR colocalization ≥ median) dot plot showing IgA–pIgR colocalized signal among DAPI⁺PCK⁺ cells. Bottom right, scattered graph showing number of IgA–pIgR colocalized cells (averaged from duplicated cores) per mm² of PCK⁺ (mean ± s.e.m., n = 273). f, Increased numbers of cells with IgA–pIgR colocalization per PCK⁺ tumour islet area (averaged from duplicated cores) are associated with improved outcome (threshold, median; P = 0.0116, H. Lee Moffett Cancer Centre cohort (MCC) (right); P = 0.0002, New England Case–Control study cohort (NECC) (left)). g, Density of IgA-coated cells (averaged from duplicated cores) in tumour islets (cells per mm² PCK⁺ area) is associated with improved outcome (P = 0.0110 for MCC (right) and P = 0.0054 for NECC (left) cohorts). *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001, two-sided log-rank (Mantel–Cox) test.

Source data