B Cells Increase Myocardial Inflammation by Suppressing M2 Macrophage Polarization in Coxsackie Virus B3-Induced Acute Myocarditis

• Published in: Inflammation 2019-06, Vol.42 (3), p.953-960
• Main Authors: Li, Yong, Huang, Yanlan, Wu, Weifeng, Wei, Bin, Qin, Lin
• Format: Article
• Language: English
• Subjects: Acute Disease; Animals; B-Lymphocytes - immunology; B-Lymphocytes - physiology; Biomedical and Life Sciences; Biomedicine; Coxsackievirus Infections - pathology; Coxsackieviruses; Disease Models, Animal; Enterovirus B, Human; Heart diseases; Immunology; Inflammation - immunology; Internal Medicine; Lymphocytes B; Macrophages; Macrophages - immunology; Mice; Mice, Inbred C57BL; Myocarditis; Myocarditis - immunology; Myocarditis - pathology; Myocarditis - virology; Original Article; Pathology; Pharmacology/Toxicology; Polarization; Rheumatology; Spleen
• ISSN: 0360-3997; 1573-2576
• DOI: 10.1007/s10753-018-0950-0

The role of B cells in viral myocarditis (VMC) remains controversial. In order to establish a role and mechanism of action for B cells in acute VMC, we established an acute VMC mouse model by intraperitoneal injection of Coxsackie virus group B type 3 (CVB3). At day 7, mice were analyzed using myocardial histopathology, and the presence of M2 macrophages in spleen and heart. Mice were divided into four groups, all having a C57BL/6 background: control group; wild-type (WT) VMC; mMt/mMt (−/−) VMC (BKO), and BKO + B cell VMC. A role for B cells was demonstrated by a significant reduction in myocardial pathological score and an increase in the frequency of M2 macrophages in the BKO group, when compared to the WT group. Once BKO mice underwent B cell reconstitution with isolated WT B cells, the myocardial pathological score was increased significantly, while the frequency of M2 macrophages decrease. Our findings demonstrate that B cells increase myocardial inflammation by suppressing M2 polarization in acute VMC in vivo .