Protective memory responses are modulated by priming events prior to challenge

Abstract

Human infections with highly pathogenic H5N1 avian influenza A viruses in the last decade have legitimized fears of a long-predicted pandemic. We thus investigated the response to secondary infections with an engineered, but still highly virulent, H5N1 influenza A virus in the C57BL/6 mouse model. Mice primed with the H1N1 A/Puerto Rico/8/34 (PR8) virus were partially protected from lethality following respiratory infection with the modified H5N1 virus A/Vietnam/1203/04 (ΔVn1203). In contrast, those that had been comparably exposed to the HKx31 (H3N2) virus succumbed to the ΔVn1203 challenge, despite similarities in viral replication, weight loss, and secondary CD8 +-T-cell response characte..