Fig. 1

Immunoreactivity of IgG in microglia of the brains of infant mice. (A–E) Sagittal sections of C57BL/6J mice at postnatal day 8 (P8) were immunolabeled with an anti-Iba1 antibody (green) and anti-mouse IgG antibody (red). Scale bars, 50 μm. (F, G) Sagittal sections of mice at P8 were immunolabeled with anti-Iba1 antibody (green) and anti-CD16/32 antibody (red). Scale bars, 100 μm. (H) Flow cytometry data showing staining of microglia with specific antibodies (red) and isotype control (black) at P8. (I) Flow cytometry quantification of the expression of CD16, CD32, and CD64 in microglia is indicated by fluorescence intensity. Ctrl, isotype control. The p-values from Student’s t-test are indicated. (J) Representative plots of flow cytometry data showing staining of microglia with anti-mouse IgG antibodies and isotype control at P8, with or without fixation and permeabilization. (K) Quantification of the percentage of microglia stained with anti-mouse IgG, with (red) or without (blue) fixation and permeabilization, at P0, P4, P8, and P12 [P0 with permeabilization (n = 3); P0 without permeabilization (n = 3); P4 with permeabilization (n = 4); P4 without permeabilization (n = 3); P8 with permeabilization (n = 7); P8 without permeabilization (n = 3); P12 with permeabilization (n = 3); P12 without permeabilization (n = 3)]. Two-way analysis of variance revealed a significant effect on localization (p < 0.0001) and stage (p < 0.0001). P-values from Fisher’s protected least-significant difference (PLSD) post hoc tests for pairwise comparisons are indicated