Fig. 4. Adoptive transfer of wild-type (WT) splenocytes into rag^−/− mice does not induce weight loss following SARS-CoV-2 MA10 infection.

(A) Phosphate-buffered saline (PBS) or WT splenocytes were adoptively transferred into WT or rag^−/− mice (rag^−/− AT), respectively, at least 1 day before infection. On day 0, the animals were infected with 1 × 10⁵ PFU/mouse SARS-CoV-2 MA10 and weight was monitored daily. On day 3 after infection, the animals were euthanized, and lungs were collected for flow cytometry, qPCR, and histology. (B) Percent weight change in WT, rag^−/−, and rag^−/− adoptive transfer (AT) mice following infection. WT: n = 8, rag^−/−: n = 4, rag^−/− AT: n = 6; experiments were performed four times. Two-way ANOVA with Tukey’s multiple comparisons test. (C) Viral RNA levels from the lungs of infected animals at day 3 after infection; experiments were performed once. One-way ANOVA with Dunn’s multiple comparisons test. (D) H&E staining of lung sections; experiments were performed once. (E) Pathological scoring of the lung sections; experiments were performed once. Two-tailed Mann-Whitney test. (F to M) Flow cytometry of lung cells from day 3 after infection; experiments were performed once. (F) Number of neutrophils (CD11b⁺ and Ly6G^high). (G) Number of monocyte-derived macrophage (CD11b⁺, Ly6G⁻, CD11C⁺, and F4/80⁺). (H) Percentage of MHC-II⁺ monocyte-derived macrophages. For (F) to (H), one-way ANOVA with Tukey’s multiple comparisons test. (I) Number of γδ⁺ T cells. Two-tailed Mann-Whitney test. (J) CD4⁺ T cells (TCRβ⁺ and CD4⁺). (K) Percentage of effector CD4⁺ T cells (TCRβ⁺, CD4⁺, CD62L⁻, and CD44⁺). (L) Number of CD8⁺ T cells (TCRβ⁺ and CD8⁺). (M) Percentage of effector CD8⁺ T cells (TCRβ⁺, CD8⁺, CD62L⁻, and CD44⁺). For (J) to (M), two-tailed t test. For (C) to (M), WT: n = 6, rag^−/−: n = 5, rag^−/− AT: n = 6.