Progress toward vaccines against viruses that cause heart disease

Of the numerous viruses that have been implicated as causes of viral inflammatory cardiomyopathy, only the 6 serotypes of the group B coxsackieviruses (CVB 1-6) and adenovirus type 2 (Ad 2) have been regularly linked to heart disease on the ba sis of both clinical investigations as well as animal models (in the case of the coxsackieviruses). Of these, only the coxsackieviruses offer a truly well-characterized system for not only investigations using a small animal disease model (myocarditis in mice) but for studies of the virus at the molecular level and in cell culture systems. The pending worldwide eradication of the related enteroviruses, the polioviruses, will further emphasize the importance of the coxsackieviruses in years to come. Studies using poliovirus have shown that enteroviruses can be attenuated for disease to create highly successful and safe hu-man vaccines. Furthermore, using recombinant DNA approaches, strains of polioviruses have been created that demonstrate a human enterovirus can express small proteins as well as foreign antigenic epitopes, thus creating multivalent chimeric vaccine strains of virus. Our laboratory has been exploring coxsackievirus 3-based vectors as models for both multivalent chimeric vaccines as well as expression vectors. The coxsackievirus can be successfully attenuated using both point mutations as well as chimeric genome technology. The coxsackievirus can also express intact small proteins in biologically active form as well as antigenic epitopes. Although it is doubtful that the marketplace will support the development of antiviral vaccines to combat human heart disease at present, the technology exists to make such vaccines a reality.