Maize-Produced Ag2 as a Subunit Vaccine for Valley Fever

Area of Science:

• Mycology
• Immunology
• Biotechnology

Background:

• Coccidioides causes San Joaquin Valley fever, a prevalent fungal disease.
• Previous vaccine development efforts over two decades have been unsuccessful.
• Expressing the candidate antigen, Antigen 2 (Ag2), in E. coli is challenging.

Purpose of the Study:

• To accumulate high levels of recombinant Ag2 in maize.
• To evaluate the immunogenicity and efficacy of maize-derived Ag2 in a mouse model.
• To explore novel vaccine delivery and adjuvant systems.

Main Methods:

• Maize transformation to express recombinant Ag2.
• Immunization of mice with Ag2 (from E. coli or maize) loaded into glucan chitin particles.
• Oral delivery of Ag2 fused to a dendritic cell carrier peptide (DCpep).
• Assessment of fungal load reduction and immune response (T-helper type 17).

Main Results:

• Transformed maize lines achieved high accumulation of recombinant Ag2 (>1 g/kg).
• Mice immunized with Ag2 (maize or E. coli derived) showed reduced fungal load after challenge.
• Oral delivery of Ag2-DCpep induced a protective T-helper type 17 immune response.

Conclusions:

• Maize serves as a viable platform for producing recombinant Coccidioides antigen Ag2.
• Glucan chitin particles and oral delivery of Ag2-DCpep show potential as vaccine components.
• Further research is needed to optimize administration for a Coccidioides vaccine.