Objective:

This study aimed to compare the susceptibility of different mouse strains to H1N1-PR8 influenza A virus (IAV) infection.

Materials and Methods:

The virus was produced in 293T/ Madin-Darby canine kidney (MDCK) cells following a plasmid rescue protocol and then used to infect males of BALB/c, CD1 IGS (CD-1 imprinting control strain), and National Institutes of Health (NIH) Swiss mouse strain as well as both genders of C57BL/6J mice. Both serum virus-specific immunoglobulin M / immunoglobulin G (IgM/IgG) and interferon-gamma (IFN-ɣ) levels, as well as H1N1-RNA in lungs of infected mouse strains, were investigated.

Results:

Differential body weight with superior loss was recorded in the C57BL/6J. Differential virus-IgM/IgG levels were recorded with higher IgM in the BALB/c (p=0.001) and higher IgG in the CD1 IGS (p=0.022). The C57BL/6 males were more susceptible to H1N1 infection and mounted higher IgM compared to females (p=0.001), whereas females showed higher IgG than males (p=0.034). Differential IFN-γ levels were observed among male mice of various strains, with a notable increase in BALB/c mice (p=0.071) and a significant decrease in C57BL/6J mice (p=0.035). A significant increase in the IFN-ɣ level was recorded in C57BL/6J females compared to males (p=0.015). The viral RNA was almost equal in the lungs of the males of various infected mouse strains’ and in both genders of the infected C57BL/6J.

Conclusion:

The studied host factors can be partially implicated in the recorded differential susceptibility of various mouse strains to infection with the H1N1-PR8 IAV. Our results can help in selecting the proper mouse model for vaccine evaluation and can be translated to future human studies to identify the highly susceptible individuals to influenza infection and learn more about the host factors involved in resistance to IAV infection.

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