Purified Influenza Virus Nucleoprotein Protects Mice from Lethal Infection Wraith, David C. and Vessey, Angela E. and Askonas, Brigitte A.,, 68, 433-440 (1987), doi = https://doi.org/10.1099/0022-1317-68-2-433, publicationName = Microbiology Society, issn = 0022-1317, abstract= SUMMARY Local administration of nucleoprotein purified from X31 (H3N2) influenza A virus primed for A virus cross-reactive cytotoxic T cells and resulted in substantial protection (75 %) of mice from a lethal challenge with the heterologous mouse-adapted A/PR/8/34 (H1N1) virus. By following the course of a lethal virus challenge we found that nucleoprotein priming did not prevent virus infection but rather aided recovery. Nucleoprotein-primed mice suffered initial symptoms of infection, i.e. weight loss and surface temperature changes, but started to recover after approximately 7 days. We suggest that such heterotypic protection can be attributed to priming of A virus crossreactive cytotoxic T cells., language=, type=