Extended Data Fig. 5: B cells promote breast cancer LN metastasis though pathogenic antibodies.

(a) Qualitative analysis of normal and metastatic LNs from 4T1 tumor-bearing mice by H&E staining. Scale bars, 100 μm. (b) LN metastatic burden of normal or Bnull mice treated with PBS, normal or tumor Ig (n = 12 biologically independent animals). (c) Growth curves of tumors arising from 4T1 tumor cells in each group (n = 12 biologically independent animals). Mammary tumor growth was measured with a digital caliper. (d) Qualitative analysis of metastatic LNs from PyMT or PyMT/B^null mice treated with PBS, normal or tumor Ig by H&E staining. Scale bars, 100 μm. (e) LN metastatic burden of PyMT or PyMT/B^null mice treated with PBS, normal or tumor Ig (n = 10 biologically independent animals). (f) Lung metastatic burden of PyMT or PyMT/B^null mice treated with PBS, normal or tumor immunoglobulin (n = 10 biologically independent animals). (g) Invasion assay of 1 × 10⁵ 4T1 cells with or without immunoglobulin stimulation (n = 8 biologically independent samples). (h,i) Representative FACS staining of B cells (CD19 + ) and CD4 + T cells was detected in LNs and spleens after control or anti-CD20 antibody treatment (n = 6 biologically independent animals) (h), and proportions of B cells are also showed in histogram (i). (j) Proportions of regulatory T cell (Tregs), CD8 + T cells, macrophages and dendritic cells (DCs) related to CD4 + T cells are showed in histogram (n = 6 biologically independent animals). Unpaired two-tailed Student’s t-tests. Data are plotted as mean +/− s.d. Data are representative of two (c,h-j) and three (a,b,d-g) independent replicates.