C57bl 6 h 2b mice

5-6 weeks-old female C57BL/6 (H-2b) mice were purchased from KOATECH (Pyeongtaek, Korea). The mice were maintained under pathogen-free conditions. All experiments employing mice were performed in accordance with the Korean NIH guidelines for care and use of laboratory animals. B16-F10 murine melanoma cell line was purchased from ATCC, and it was allowed to grow in DMEM supplemented with 10% FBS and 1% antibiotic-antimycotic solution at 37°C and 5% CO₂/95% humidified air.

Six-week-old female C57BL/6 (H-2^b) mice were purchased from KOATECH (Pyeongtaek, Korea) and housed in specific pathogen-free conditions at Korea Institute of Bioscience and Biotechnology (KRIBB) in Daejeon, Korea. Mouse experiments were approved by KRIBB’s Institutional Review Board. The mouse lymphoma cell line EL-4 (H-2^b) was obtained from the Korea Cell Line Bank (Seoul, Korea) and maintained in complete Dulbecco’s modified Eagle’s medium (DMEM; Hyclone; UT, USA) supplemented with 10 % fetal bovine serum (FBS; Hyclone). Both A/Puerto Rico/8/1934 (PR8) and A/California/04/2009 (CA04) H1N1 influenza A viruses were grown for 2 days at 37 °C in the allantoic cavities of 10-day-old fertile chicken eggs. Virus stocks were propagated in the allantoic cavity of 10-day-old, embryonated, and specific pathogen-free hen’s eggs at 37 °C. Clarified allantoic fluid was aliquoted and immediately frozen at −80 °C.