COXSACKIE B1 VIRUS-INDUCED MURINE MYOSITIS - RELATIONSHIP OF DISEASE SEVERITY TO VIRUS DOSE AND ANTIVIRAL ANTIBODY-RESPONSE

Inoculation of Coxsackie B1 virus (CB1) in newborn CD1 Swiss mice indu ces a chronic myositis of proximal hindlimb muscles (CB1 myositis). To study the possible role of the virus dose, and of antiviral antibodie s in the development of CB1 myositis, we infected groups of newborn mi ce with six CB1 doses, ranging from 30 to 10,000 plaque forming units (pfu); after 4 and 8 weeks we determined morbidity and antiviral antib ody titer, and quantified histopathological changes. At 4 weeks, morbi dity and mononuclear cell infiltration differed significantly for the various groups, with the most prominent changes in 300 pfu animals. At 4 and 8 weeks diseased animals had significantly higher antibody tite rs than clinically unaffected animals, and at 4 weeks myopathic and in filtrative changes correlated positively with the serum antibody titer . Our data indicate that the virus dose plays a pathogenic role in CB1 myositis, and they suggest further study on the role of humoral immun e mechanisms in the early phase of CB1 myositis.