Antibody to influenza virus matrix protein detects a common antigen on the surface of cells infected with type A influenza viruses.

Antisera to the type-specific internal influenza virus matrix (M) protein of a type A influenza virus were produced in goats. In the presence of complement, anti-M serum was cytotoxic for target cells which were infected with a variety of serologically distinct type A influenza viruses, but did not react with type B influenza virus-infected cells. Absorption experiments indicated that anti-M serum detected a common antigen(s) on the surface of type A-infected cells. This serological cross-reactivity parallels the cross-reactivity observed for the cytotoxic T-cell response to type A viruses.