The VP1-unique region of parvovirus B19 induces myocardial injury in mice.

As a common human pathogen, parvovirus B19 (B19V) has been shown to be associated with many heart diseases, such as myocarditis, cardiomyopathy and cardiopericarditis. The virus protein 1-unique region (VP1u) is critical to B19V infectivity, but its role in the pathogenesis of B19V-induced myocardial injury has not been well studied. In this study to investigate the effects ofVP1u on the host myocardium, we first expressed a recombinant VP1u protein in Escherichia coli, produced it on a large scale by high-volume fermentation, and purified it using the AKTA explorer 100 system. Following treatment of mice with the recombinant protein, we then examined changes in the morphology of the cardiac muscles, the titre of anti-VP1u protein antibodies, and a panel of heart functional protein markers. Our results show that VP1u alone is sufficient to elicit pathological and ultrastructural changes in the host myocardium, and to increase the levels of the functional enzymes aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK), creatine kinase isoenzyme (CK-MB) and alpha-hydroxybutyric acid dehydrogenase (alpha-HBDH). The changes in myocardial pathology and myocardial zymogram indicate that the VP1u protein of B19V causes myocardial injury, and may largely contribute to the pathogenesis of B19V-induced heart diseases.