A Host Cell Vector Model for Analyzing Viral Protective Antigens and Host Immunity

Area of Science:

• Veterinary Virology
• Immunology
• Vaccine Development

Background:

• Avian influenza viruses (IAVs) cause significant economic losses in the poultry industry.
• Traditional vaccines often require multivalent antigens and focus on humoral immunity, with intensive production needs.
• There is a need for improved methods to evaluate antigen-specific immune responses and identify conserved viral targets for vaccine design.

Purpose of the Study:

• To establish a genetically matched host-cell system for evaluating antigen-specific immune responses to avian influenza viruses.
• To identify conserved CD8+ T cell epitopes in avian influenza viruses using this novel system.
• To explore the potential of this platform for rational vaccine design.

Main Methods:

• Development of an MHC class I genotype (B21)-matched host (SPF chicken) and cell vector (DF-1 cell line) model.
• Engineering DF-1 cells to express hemagglutinin (HA), matrix 1 (M1), and nucleoprotein (NP) genes from IAVs.
• Prime-boost immunization of haplotype-matched chickens with engineered DF-1 cells, followed by immune response evaluation (HI, VN, IFN-γ) and CD8+ T cell epitope mapping via mass spectrometry.

Main Results:

• Live HA-expressing DF-1 cells induced strong hemagglutination inhibition (HI) and virus-neutralizing (VN) antibody titers.
• DF-1 cells expressing NP induced stronger IFN-γ production than those expressing M1, differentiating cellular responses.
• Mass spectrometry identified conserved HA (97.6% of H5 IAVs) and NP (98.5% of pan-subtype IAVs) epitopes.

Conclusions:

• The developed host-cell system is effective for antigen dissection and evaluating antigen-specific immune responses.
• The identified conserved epitopes represent promising targets for rational avian influenza vaccine design.
• This approach provides insights into conserved viral targets and aids in understanding immune responses.