Maize-Produced Ag2 as a Subunit Vaccine for Valley Fever




Hayden, Celine A.
Hung, Chiung-Yu
Zhang, Hao
Negron, Austin
Esquerra, Raymond
Ostroff, Gary
Abraham, Ambily
Lopez, Alejandro Gabriel
Gonzales, Juliet Elizabeth
Howard, John A.

Journal Title

Journal ISSN

Volume Title


Oxford University Press


Coccidioides is the causative agent of San Joaquin Valley fever, a fungal disease prevalent in the semiarid regions of the Americas. Efforts to develop a fungal vaccine over the last 2 decades were unsuccessful. A candidate antigen, Antigen 2 (Ag2), is notoriously difficult to express in Escherichia coli, and this study sought to accumulate the antigen at high levels in maize. Transformed maize lines accumulated recombinant Ag2 at levels >1 g/kg. Mice immunized with this antigen and challenged with live Coccidioides arthroconidia showed a reduction in the fungal load when Ag2 derived from either E. coli or maize was loaded into glucan chitin particles. A fusion of Ag2 to dendritic cell carrier peptide (DCpep) induced a T-helper type 17 response in the spleen when orally delivered, indicative of a protective immune response. The maize production platform and the glucan chitin particle adjuvant system show promise for development of a Coccidioides vaccine, but further testing is needed to fully assess the optimal method of administration.



valley fever, Coccidioides, subunit vaccine, maize-produced vaccine, plant vaccine, glucan chitin particles, bioencapsulation


Hayden, C. A., Hung, C.-Y., Zhang, H., Negron, A., Esquerra, R., Ostroff, G., . . . Howard, J. A. (2019). Maize-Produced Ag2 as a Subunit Vaccine for Valley Fever. The Journal of Infectious Diseases, 220(4), 615-623. doi:10.1093/infdis/jiz196


Molecular Microbiology and Immunology