Figure 2.

White matter microglial reactivity after mild respiratory COVID

(A and B) Activated microglia (IBA1⁺ CD68⁺) quantification 7 days post-infection in the cingulum of the corpus callosum of (A) CD1 (n = 5 control, 4 mild COVID mice) and (B) BALB/c (n = 3 control, n = 5 mild COVID mice).

(C) Representative confocal micrographs of reactive microglia (IBA1, white; CD68, magenta) in the cingulum of the corpus callosum of BALB/c mice 7 days post-infection.

(D and E) Reactive microglia (IBA1⁺ CD68⁺) quantification 7 weeks post-infection in the cingulum of the corpus callosum of (D) CD1 (n = 7 mice/group) and (E) BALB/c (n = 5 mice/group) mice.

(F) Representative confocal micrographs of reactive microglia (IBA1, white; CD68, magenta) in the cingulum of the corpus callosum of BALB/c mice 7-weeks post-infection.

(G and H) Reactive microglia (IBA1⁺ CD68⁺) quantification 7 days post-infection in the cortical gray matter of (G) CD1 (n = 5 control, 4 mild COVID mice) and (H) BALB/c (n = 3 control, n = 5 mild COVID mice).

(I) Representative confocal micrographs of reactive microglia (IBA1, white; CD68, magenta) in the cortical gray matter of BALB/c mice 7 days post-infection.

(J and K) Reactive microglia quantification (IBA1⁺ CD68⁺) 7 weeks post-infection in the cortical gray matter of (J) CD1 (n = 7 mice/group) and (K) BALB/C (n = 5 mice/group).

(L) Representative confocal micrographs of reactive microglia (IBA1, white; CD68, magenta) in the cortical gray matter of BALB/c mice 7 weeks post-infection.

Data shown as mean ± SEM; each dot represents an individual mouse; p values shown in figure panels; ns p > 0.05 by two-tailed, unpaired t test. (C, F, I, and L) Scale bars, 50 μm.

(M) Representative micrographs of CD68 immunostaining (brown) in the gray (cerebral cortex) or subcortical white matter of human subjects with COVID or in non-COVID control subjects.

(N) Reactive microglia (CD68⁺ cells) quantification (n = 9 human subjects for each group).

Data shown as mean ± SEM; ns, p > 0.05 by two-way ANOVA with multiple comparisons; each dot represents a mouse or human subject. Scale bars, 100 μm.

See also Figures S2 and S3, Table S2, and Data S1.