T follicular helper cells are elevated in a rat model of autoimmune myocarditis

Fig. 1. Histopathology analysis. H&E staining of myocardial tissues was observed 14 or 35 days after the initial immunization. (A) Representative images of H&E staining of myocardial tissues. Scale bars: 20 μm; original magnification: ×200. (B, C) H&E staining inflammatory scores on day 14 or 35 after immunization. *P < 0.05, ****P < 0.0001. The data are expressed as mean ± SD; each experiment was n ≥ 3. Comparisons between two groups were analyzed with unpaired t‐test.

Fig. 2. Increased percentage of the CD4+CXCR5+ Tfh cells in spleen tissues of the EAM model. (A, B) The percentage of CD4+CXCR5+ Tfh cells in spleen tissues of the EAM model on day 14 after immunization. (C, D) The percentage of CD4+CXCR5+ Tfh cells in spleen tissues of the EAM model on day 35 after immunization. **P < 0.01. The data are expressed as mean ± SD; each experiment was n ≥ 3. Comparisons between two groups were analyzed with unpaired t‐test.

Fig. 3. Increased percentage of CD4+CXCR5+ Tfh cells in myocardial tissues of the EAM model. (A, B) The percentage of CD4+CXCR5+ Tfh cells in myocardial tissues of the EAM model on day 14 after immunization. (C, D) The percentage of CD4+CXCR5+ Tfh cells in myocardial tissues of the EAM model on day 35 after immunization. **P < 0.01. The data are expressed as mean ± SD; each experiment was n ≥ 3. Comparisons between two groups were analyzed with unpaired t‐test.

Fig. 4. Increased percentage of the CD19+ B cells in spleen tissues of the EAM model. (A, B) The percentage of CD19+ B cells in spleen tissues of the EAM model on day 14 after immunization. (C, D) The percentage of CD19+ B cells in spleen tissues of the EAM model on day 35 after immunization. ***P < 0.001. The data are expressed as mean ± SD; each experiment was n ≥ 3. Comparisons between two groups were analyzed with unpaired t‐test.

Fig. 5. Elevated expression levels of IL‐21, CXCL13 and MYSAb in the serum of rats with EAM. (A, B) ELISA results showing the expression level of IL‐21 in the serum of rats with EAM on day 14 or 35 after immunization. (C, D) The expression level of CXCL13 in the serum of rats with EAM on day 14 or 35 after immunization using ELISA. (E, F) The expression level of MYSAb in the serum of rats with EAM on day 14 or 35 after immunization using ELISA. ***P < 0.001. The data are expressed as mean ± SD; each experiment was n ≥ 3. Comparisons between two groups were analyzed with unpaired t‐test.

Fig. 6. Elevated expression levels of IL‐21 and CXCL13 in myocardial tissues of rats with EAM. (A, B) qRT‐PCR results showing the expression levels of IL‐21 and CXCL13 in myocardial tissues of rats with EAM on day 14 after immunization. (C, D) qRT‐PCR results showing the expression levels of IL‐21 and CXCL13 in myocardial tissues of rats with EAM on day 35 after immunization. *P < 0.05. The data are expressed as mean ± SD; each experiment was n ≥ 3. Comparisons between two groups were analyzed with unpaired t‐test.

Fig. 7. Tfh cells in the serum of rats with EAM can produce increased levels of IL‐21 and CXCL13. (A, B) ELISA results showing the expression level of IL‐21 and CXCL13 in Tfh cells on day 14 after immunization. (C, D) ELISA results showing the expression level of IL‐21 and CXCL13 in Tfh cells on day 35 after immunization. ****P < 0.0001. The data are expressed as mean ± SD; each experiment was n ≥ 3. Comparisons between two groups were analyzed with one‐way ANOVA.

Fig. 8. Tfh cells in the serum of rats with EAM promote B cell viability in vitro on day 14 (A) or 35 (B) after immunization. *P < 0.05, ***P < 0.001, ****P < 0.0001. The data are expressed as mean ± SD; each experiment was n ≥ 3. Comparisons between two groups were analyzed with one‐way ANOVA.