Characteristics of the protective subcellular coccidioidal T27K vaccine

Ex Vivo Cytokine Release, Determined by a Multiplex Cytokine Assay, in Response to Coccidioidal Antigen Stimulation of Whole Blood among Subjects with Recently Diagnosed Primary Pulmonary Coccidioidomycosis

Coccidioidomycosis, commonly known as Valley fever, is a common pneumonia in the southwestern United States. In this paper, we examined the release of 30 inflammatory proteins in whole-blood samples obtained from persons with coccidioidal pneumonia after the blood samples were incubated with a preparation made from the causative fungus, Coccidioides. We found that six of these proteins, all cytokines, were specifically released in high concentrations in these patients. Three of the cytokines were seen very early in disease, and an assay for all six might serve as a marker for the early diagnosis of Valley fever.

The elements of the cellular immune response in human coccidioidomycosis remain undefined. We examined the ex vivo release of an array of inflammatory proteins in response to incubation with a coccidioidal antigen preparation to ascertain which of these might be associated with diagnosis and outcome. Patients with a recent diagnosis of primary pulmonary coccidioidomycosis and a control group of healthy subjects were studied. Blood samples were incubated for 18 h with T27K, a soluble coccidioidal preparation containing multiple glycosylated antigens, and the supernatant was assayed for inflammatory proteins using the multiplex Luminex system. The presentation and course of illness were compared to the levels of the inflammatory proteins. Among the 31 subjects studied, the median time from diagnosis to assay was 15 days. Of the 30 inflammatory proteins measured, the levels of only 7 proteins, granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-1 receptor alpha (IL-1RA), interleukin-1β (IL-1β), interferon gamma (IFN-γ), IL-2, IL-13, and tumor necrosis factor alpha (TNF-α), were more than 10-fold above the levels seen without antigen stimulation. The levels of IFN-γ and IL-2 were significantly elevated in those subjects not receiving triazole antifungal therapy compared to those who were receiving triazole antifungal therapy. While the levels of IL-1RA were nonspecifically elevated, elevated levels of IL-13 were seen only in those with active pulmonary coccidioidomycosis. Only six cytokines were specifically increased in subjects with recently diagnosed primary pulmonary coccidioidomycosis. While IFN-γ, IL-2, and TNF-α have been previously noted, the finding of elevated levels of the innate cytokines GM-CSF and IL-1β could suggest that these, as well as IL-13, are early and specific markers for pulmonary coccidioidomycosis.

IMPORTANCE Coccidioidomycosis, commonly known as Valley fever, is a common pneumonia in the southwestern United States. In this paper, we examined the release of 30 inflammatory proteins in whole-blood samples obtained from persons with coccidioidal pneumonia after the blood samples were incubated with a preparation made from the causative fungus, Coccidioides. We found that six of these proteins, all cytokines, were specifically released in high concentrations in these patients. Three of the cytokines were seen very early in disease, and an assay for all six might serve as a marker for the early diagnosis of Valley fever.

Viable spores of Coccidioides posadasii Δcps1 are required for vaccination and provide long lasting immunity

Coccidioidomycosis is a systemic fungal infection for which a vaccine has been sought for over fifty years. The avirulent Coccidioides posadasii strain, Δcps1, which is missing a 6 kb gene, showed significant protection in mice. These studies explore conditions of protection in mice and elucidate the immune response. Mice were vaccinated with different doses and viability states of Δcps1 spores, challenged with virulent C. posadasii, and sacrificed at various endpoints, dependent on experimental objectives. Tissues from vaccinated mice were harvested for in vitro elucidation of immune response. Vaccination with viable Δcps1 spores was required for protection from lethal challenge. Viable spore vaccination produced durable immunity, lasting at least 6 months, and prolonged survival (≥6 months). The C. posadasii vaccine strain also protected mice against C. immitis (survival ≥ 6 months). Cytokines from infected lungs of vaccinated mice in the first four days after Cp challenge showed significant increases of IFN-γ, as did stimulated CD4⁺ spleen cells from vaccinated mice. Transfer of CD4⁺ cells, but not CD8⁺ or B cells, reduced fungal burdens following challenge. IFN-γ from CD4⁺ cells in vaccinated mice indicates a Th1 response, which is critical for host control of coccidioidomycosis.

Distance from construction site and risk for coccidioidomycosis, Arizona, USA

Coccidioides spp. fungi, which are present in soil in the southwestern United States, can become airborne when the soil is disrupted, and humans who inhale the spores can become infected. In 2012, our institution in Maricopa County, Arizona, USA, began a building project requiring extensive excavation of soil. One year after construction began, we compared the acquisition of coccidioidomycosis in employees working adjacent to the construction site (campus A) with that of employees working 13 miles away (campus B). Initial testing indicated prior occult coccidioidal infection in 20 (11.4%) of 176 campus A employees and in 19 (13.6%) of 140 campus B employees (p = 0.55). At the 1-year follow-up, 3 (2.5%) of 120 employees from campus A and 8 (8.9%) of 90 from campus B had flow cytometric evidence of new coccidioidal infection (p = 0.04). The rate of coccidioidal acquisition differed significantly between campuses, but was not higher on the campus with construction.

Identification, molecular characterization, and expression analysis of a DOMON-like type 9 carbohydrate-binding module domain-containing protein of Coccidioides posadasii

Previously, we investigated the effect of N-acetylglucosamine (GlcNAc) on Coccidioides posadasii chitinolytic enzymes during in vitro spherule-endospore (S/E) phase culture. During those studies, sodium dodecyl sulfatepolyacrylamide gel electrophoresis analysis of supernatants from S/E phase cultures grown in Converse medium with or without added GlcNAc revealed a ∼ 28-kDa band (CFP28), whose abundance was increased by GlcNAc in parallel with the chitinolytic enzymes. Mass spectrometry (MS) of the CFP28 band revealed peptides that matched an open reading frame found in the tentative consensus sequence, TC20325, retrieved from the Dana Farber Cancer Institute C. posadasii Gene Index Database. The TC20325 cDNA sequence was used to design internal primers based on MS peptides and a full-length cDNA was isolated using a combination of rapid amplification of cDNA ends and reverse transcription-polymerase chain reaction. The deduced amino acid sequence of the full-length cDNA consists of 231 amino acid residues with a 19 aa signal peptide. The mature protein has a calculated molecular mass of ∼ 24.5 kDa, a theoretical pI of 6.09, and consists of a single DOMON-like type 9 carbohydrate-binding module (CBM9-like-3) conserved domain. The protein shares the highest sequence similarity (≥57%) to hypothetical proteins from fungi within the Pezizomycotina subphylum of Ascomycota. Antiserum against a recombinant version of CFP28 recognized native CFP28 in S/E phase cells and culture supernatants. CFP28 mRNA and protein expression were detectable in S/E phase in Converse medium, but were increased in the presence of added GlcNAc. Purified native CFP28 reacted with pooled sera from patients with coccidioidomycosis.

Progress Toward a Human Vaccine Against Coccidioidomycosis

Coccidioidomycosis (San Joaquin Valley fever) is a human respiratory disease caused by a soil-borne mold, and is recognized as an intransigent microbial infection by physicians who treat patients with the potentially life-threatening, disseminated form of this mycosis. Epidemiological studies based on surveys of skin-test reactivity of people who reside in the endemic regions of the Southwestern US have shown that at least 150,000 new infections occur annually. The clinical spectrum of coccidioidomycosis ranges from an asymptomatic insult to a severe pulmonary disease in which the pathogen may spread from the lungs to the skin, bones, brain and other body organs. Escalation of symptomatic infections and increased cost of long-term antifungal treatment warrant a concerted effort to develop a vaccine against coccidioidomycosis. This review examines recently reported strategies used to generate such a vaccine and summarizes current understanding of the nature of protective immunity to this formidable disease.

Fungal cell wall vaccines: an update

This discussion is intended to be an overview of current advances in the development of fungal cell wall vaccines with an emphasis on Candida; it is not a comprehensive historical review of all fungal cell wall vaccines. Selected, more recent, innovative strategies for developing fungal vaccines will be highlighted. Both scientific and logistical obstacles related to the development of, and clinical use of, fungal vaccines will be discussed.

The public health impact of coccidioidomycosis in Arizona and California

The numbers of reported cases of coccidioidomycosis in Arizona and California have risen dramatically over the past decade, with a 97.8% and 91.1% increase in incidence rates from 2001 to 2006 in the two states, respectively. Of those cases with reported race/ethnicity information, Black/African Americans in Arizona and Hispanics and African/Americans in California experienced a disproportionately higher frequency of disease compared to other racial/ethnic groups. Lack of early diagnosis continues to be a problem, particularly in suspect community-acquired pneumonia, underscoring the need for more rapid and sensitive tests. Similarly, the inability of currently available therapeutics to reduce the duration and morbidity of this disease underscores the need for improved therapeutics and a preventive vaccine.

Saccharomyces cerevisiae as a vaccine against coccidioidomycosis

Disseminated coccidioidomycosis is a life-threatening infection. In these studies, we examined protection against systemic murine coccidioidomycosis by vaccination with heat-killed Saccharomyces cerevisiae (HKY). CD-1 mice received HKY subcutaneously or by oral gavage with or without adjuvants once weekly beginning 3 or 4 weeks prior to infection; oral live Saccharomyces was also studied. All HKY sc regimens were equivalent, prolonging survival (P<or=0.005) and reducing fungal burden versus controls. Oral live Saccharomyces, but not HKY, prolonged survival (P=0.03), but did not reduce fungal burden. Survival of mice given HKY was equivalent to vaccination with formalin-killed spherules, but inferior in reduction of fungal burden. HKY was superior to a successful recombinant vaccine, PRA plus adjuvant. This novel heterologous protection afforded by HKY vaccination offers a new approach to a vaccine against coccidioidomycosis.

Vaccine-induced cellular immune responses differ from innate responses in susceptible and resistant strains of mice infected with Coccidioides posadasii

Susceptibility to Coccidioides spp. varies widely in humans and other mammals and also among individuals within a species. Among strains of mice with various susceptibilities, immunohistopathology revealed that C57BL/6 mice were highly susceptible to the disease following intranasal infection, DBA/2n mice were intermediate, and Swiss-Webster mice were innately resistant. Resistant Swiss-Webster mice developed prominent perivascular/peribronchiolar lymphocytic cuffing and well-formed granulomas with few fungal elements and debris in the necrotic center, surrounded by a mantle of macrophages, lymphocytes, and fibrocytes. Susceptible C57BL/6 mice became moribund between 14 and 18 days postinfection, with overwhelming numbers of neutrophils and spherules and very few T cells, the drastic reduction of which was associated with failure and death, while intermediate DBA/2n mice controlled the fungal burden but demonstrated progressive lung inflammation with prominent suppuration, and they deteriorated clinically. Vaccinated C57BL/6 mice had an early and robust lymphocyte response, which included significantly higher Mac2(+), CD3(+), and CD4(+) cell scores on day 18 than those of innately resistant SW mice and DBA/2n mice; they also had prominent perivascular/peribronchiolar lymphocytic infiltrates not present in their unvaccinated counterparts, and they appeared to be resolving lesions by day 56 compared to the other two strains, based on significantly lower disease scores and observably smaller and fewer lesions with few spherules and neutrophils.