Perforin is essential for control of ectromelia virus but not related poxviruses in mice

Lack of perforin renders the relatively resistant mouse strain C57BL/6 high ly susceptible to the natural mouse pathogen ectromelia virus, a cytopathic orthopoxvirus. This is indicated by increased mortality, elevated virus ti ters and pathology in liver and spleen, and increased levels of liver enzym es in blood. Cowpox virus on the other hand is more virulent in the presenc e of perforin than in its absence. An additional lack of granzyme A which t ogether with perforin is a constituent of cytoplasmic granules from cytotox ic T cells increases the virulence of cowpox virus.