Heterotypic interference between influenza viruses A/Aichi/2/68 and B/Massachusetts/1/71.

Virus particles produced by MDCK cells mixedly infected with 3 PFU/cell each of A/Aichi/2/68 (H3N2) (Aichi) and B/Massachusetts/1/71 (Mass) influenza viruses exclusively possessed haemagglutinin (HA) of Mass, although approximately one-fifth of the mixed yield had coding potential for Aichi serotype. Synthesis of major viral proteins of Aichi was markedly suppressed by co-infecting Mass. By increasing the multiplicity of co-infecting Aichi to 30 PFU/cell, interference became reciprocal. Aichi interfered with replication of Mass more severely than Mass did with replication of Aichi. All the major viral proteins of both Aichi and Mass were expressed within the infected cells.