DNA vaccination against La Crosse virus

Area of Science:

• Virology
• Immunology
• Vaccinology

Background:

• Effective vaccine development, including DNA vaccines, requires suitable animal models.
• Many emerging zoonotic viruses lack appropriate animal models for research.
• Interferon-alpha/beta receptor (IFNAR-1)-deficient mice offer a novel model due to high viral susceptibility.

Purpose of the Study:

• To establish and validate a small animal model for DNA vaccine evaluation.
• To assess the efficacy of DNA vaccines encoding specific viral proteins in this new model.
• To investigate the role of adjuvants in enhancing DNA vaccine responses.

Main Methods:

• Development of interferon-alpha/beta receptor (IFNAR-1)-deficient mice.
• DNA vaccination using plasmids encoding viral envelope proteins (G1, G2) or nucleocapsid protein (N).
• Assessment of protection against lethal viral challenge in vaccinated mice.
• Evaluation of interleukin-12 (IL-12) as an adjuvant for DNA vaccines.

Main Results:

• IFNAR-1-deficient mice are highly susceptible to viral infections but mount normal immune responses.
• A single DNA injection encoding viral envelope proteins G1 and G2 conferred complete protection.
• DNA vaccination with the nucleocapsid protein N showed limited efficacy.
• IL-12 as an adjuvant improved survival but its effect was independent of the N protein, suggesting innate immune involvement.

Conclusions:

• IFNAR-1-deficient mice represent a valuable small animal model for DNA vaccine research.
• DNA vaccines targeting viral envelope proteins are effective in this model.
• IL-12's adjuvant effect highlights the importance of innate immunity, such as NK cells, in vaccine responses.