Coccidioides is an airborne fungal pathogen that can cause mild to severe respiratory disease (coccidioidomycosis;San Joaquin Valley fever) in immunocompetent individuals. The fungus inhabits desert soil in the Southwestern U.S. between West Texas and Southern California. About 20 million people reside in the endemic region. Although rarely a life-threatening disease, Coccidioides causes significant morbidity in more than 40% of infected individuals, and is responsible for high health care costs related to long term treatment. Although about half of the Coccidioides-infected individuals experience only mild discomfort and do not seek medical intervention, a large body of clinical evidence suggests that reactivation of the respiratory disease may occur months to years after the original insult. Recovery from symptomatic infection typically confers lifelong immunity to reinfection, suggesting that vaccination against coccidioidomycosis is feasible. We have shown that disease- susceptible BALB/c and C57BL/6 mice can be fully protected against coccidioidal infection by vaccination with a genetically engineered, avirulent strain of the pathogen. Preliminary studies have revealed that a detergent extracted protein fraction of the parasitic cell wall of this mutant strain protects mice against pulmonary coccidioidomycosis. In this proposal we outline a novel strategy to develop an epitope-driven chimeric vaccine based upon a subset of cell wall-derived antigens of the live vaccine strain of Coccidioides that interface with the host immune system and elicit a protective response against coccidioidal infection.
In Specific Aim 1, we will identify, structurally characterize, express and test in a murine model of coccidioidomycosis the protective efficacy of T-cell-reactive proteins (Tcrp) derived from parasitic cell wall extracts of the genetically-engineered vaccine strain of Coccidioides.
In Specific Aim 2, we will compare the protective efficacy of non-glycosylated recombinant proteins selected on the basis of Specific Aim 1 to genetically-engineered N- glycosylated, O-glycosylated, and both N- and O-glycosylated forms of the same selected recombinant proteins, and evaluate the involvement of mannose receptors in the stimulation of protective immunity.
In Specific Aim 3, we will incorporate selected promiscuous, human major histocompatibility complex ((MHC) II-binding epitopes identified in vaccine candidates with the highest protective efficacy, as determined by Specific Aims 1 and 2, into a chimeric vaccine and evaluate its ability to protect human MHCII-expressing transgenic mice against pulmonary infection with Coccidioides. We argue that this epitope-driven vaccine can simultaneously direct the immune response to multiple dominant and subdominant epitopes and, thereby, induce robust and durable protection against coccidioidomycosis.
The goal of this proposal is to develop an epitope-driven, recombinant protein-based vaccine against coccidioidomycosis (San Joaquin Valley fever), which will first be evaluated in a transgenic murine model of the respiratory disease (this project), and ultimately moved forward to human clinical trial.
|Hung, Chiung-Yu; Castro-Lopez, Natalia; Cole, Garry T (2016) Card9- and MyD88-Mediated Gamma Interferon and Nitric Oxide Production Is Essential for Resistance to Subcutaneous Coccidioides posadasii Infection. Infect Immun 84:1166-75|
|Hurtgen, Brady J; Castro-Lopez, Natalia; JimÃ©nez-Alzate, Maria Del Pilar et al. (2016) Preclinical identification of vaccine induced protective correlates in human leukocyte antigen expressing transgenic mice infected with Coccidioides posadasii. Vaccine 34:5336-5343|
|Hung, Chiung-Yu; Wozniak, Karen L; Cole, Garry T (2016) Flow Cytometric Analysis of Protective T-Cell Response Against Pulmonary Coccidioides Infection. Methods Mol Biol 1403:551-66|
|WÃ¼thrich, Marcel; Brandhorst, Tristan T; Sullivan, Thomas D et al. (2015) Calnexin induces expansion of antigen-specific CD4(+) T cells that confer immunity to fungal ascomycetes via conserved epitopes. Cell Host Microbe 17:452-65|
|Hung, Chiung-Yu; Castro-Lopez, Natalia; Cole, Garry T (2014) Vaccinated C57BL/6 mice develop protective and memory T cell responses to Coccidioides posadasii infection in the absence of interleukin-10. Infect Immun 82:903-13|
|Wang, Huafeng; LeBert, Vanessa; Hung, Chiung Yu et al. (2014) C-type lectin receptors differentially induce th17 cells and vaccine immunity to the endemic mycosis of North America. J Immunol 192:1107-19|
|Hung, Chiung-Yu; JimÃ©nez-Alzate, MarÃa del Pilar; Gonzalez, Angel et al. (2014) Interleukin-1 receptor but not Toll-like receptor 2 is essential for MyD88-dependent Th17 immunity to Coccidioides infection. Infect Immun 82:2106-14|
|Cole, Garry T; Hung, Chiung-Yu; Sanderson, Sam D et al. (2013) Novel strategies to enhance vaccine immunity against coccidioidomycosis. PLoS Pathog 9:e1003768|
|Wise, Hua Zhang; Hung, Chiung-Yu; Whiston, Emily et al. (2013) Extracellular ammonia at sites of pulmonary infection with Coccidioides posadasii contributes to severity of the respiratory disease. Microb Pathog 59-60:19-28|
|Cole, Garry T; Hurtgen, Brady J; Hung, Chiung-Yu (2012) Progress Toward a Human Vaccine Against Coccidioidomycosis. Curr Fungal Infect Rep 6:235-244|
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