Coccidioidomycosis. In: Murphy JW, Friedman H, Bendinelli M, editors. Fungal Infections and Immune Responses. Boston: Springer US; 1993. pp. 173-211. [DOI: 10.1007/978-1-4899-2400-1_8]

Coccidioidomycosis--a fungal disease of the Americas

Coccidioidomycosis was first recognized as a serious disease over 100 years ago, but the disease remains an enigma and often goes undiagnosed, even in endemic areas

Successful treatment of a critically ill patient with disseminated coccidioidomycosis, using adjunctive interferon-gamma

Conventional antifungal therapy was not successful for a critically ill patient who had been hospitalized for 137 days in the intensive care unit with disseminated Coccidioides immitis infection and respiratory failure. The addition of interferon- gamma to the therapeutic regimen resulted in improvement and discharge from the hospital. Adjunctive interferon- gamma used in the successful treatment of severe coccidioidomycosis has not been reported previously.

Role of signal sequence in vaccine-induced protection against experimental coccidioidomycosis

The vaccine efficacy of the gene sequence encoding the signal peptide of the antigen known as antigen 2 or proline-rich antigen (Ag2/PRA), an immunodominant antigen present in the cell wall of the fungal pathogen Coccidioides immitis, was investigated in a murine model of coccidioidomycosis. Expression plasmids for Ag2/PRA(1-18) DNA (signal sequence), Ag2/PRA(19-194) DNA (lacking the signal sequence), and Ag2/PRA(1-194) DNA (full length) were inserted in the pVR1012 vector, and the constructs were used to vaccinate the highly susceptible BALB/c mouse strain. Immunization with the signal gene sequence significantly reduced the fungal burden in the lungs and spleens of mice 12 days after intraperitoneal challenge with a lethal dose of 2,500 C. immitis arthroconidia, to a level comparable to the protection induced in mice immunized with the full-length Ag2/PRA(1-194) DNA. The Ag2/PRA(19-194) gene protected mice but to a significantly lower level than the signal sequence or the full-length Ag2 gene. The immunizing capacity of Ag2/PRA(1-18) was not attributable to a nonspecific immunostimulatory effect of DNA, as evidenced by the fact that mice immunized with a frameshift mutation of Ag2/PRA(1-18) were not protected against challenge. Furthermore, a synthetic peptide corresponding to the translated sequence of Ag2/PRA(1-18) DNA protected mice, albeit at a lower level than the Ag2/PRA(1-18) DNA vaccine. The protection induced with the signal gene vaccine correlated with the production of gamma interferon when splenocytes from Ag2/PRA(1-18)-immunized mice were stimulated with recombinant full-length Ag2 and was not associated with the production of anti-Coccidioides immunoglobulin G antibody. This is the first study to establish that a signal peptide sequence alone, administered as a gene vaccine or synthetic peptide, can induce protective immunity against a microbial pathogen.

Involvement of CD4+ T cells and macrophages in acquired protection against infection with Sporothrix schenckii in mice

The cell-mediated immune response against infection with Sporothrix schenckii was investigated in vivo and in vitro. Following primary infection, mice were protected against a secondary subcutaneous inoculation with S. schenckii as determined by the local growth of fungi, and subcutaneously immunized mice were able to survive a lethal intravenous infection. Protection could be transferred to naive congenitally athymic nude mice using lymph node cells taken from immune mice. When immune lymph node cells had CD4+ cells depleted by antibody plus complement, the ability to transfer protection was significantly reduced. Treatment of mice with carrageenan, a macrophage blocker, before and after secondary inoculation abolished protection. An in vitro system, using either immune lymph node cells alone or macrophages alone, failed to kill the organism. However, inhibition of fungal growth was observed when both immune lymph node cells and macrophages were combined. Growth inhibition in vitro was reduced after depletion of CD4+ cells but not CD8+ cells. Addition of anti-interferon (IFN)-gamma monoclonal antibodies (MAb) also reduced growth inhibition. By using reverse transcription-polymerase chain reaction (RT-PCR) analysis, it was shown that immune lymph node cells expressed message for IFN-gamma, tumour necrosis factor (TNF)-alpha and interleukin (IL)-10 after stimulation with heat-killed S. schenckii. These results suggest that acquired immunity against S. schenckii is expressed mainly by macrophages activated by CD4+ T cells.

Genetic vaccination against Coccidioides immitis: comparison of vaccine efficacy of recombinant antigen 2 and antigen 2 cDNA

Previous studies from our laboratory established that C-ASWS, an alkali-soluble, water-soluble extract from cell walls of Coccidioides immitis, protects mice against lethal challenge with this fungus. The C-ASWS extract contains a glycosylated protein, designated antigen 2 (Ag2), and a polysaccharide antigen. We recently cloned Ag2 cDNA and showed that the recombinant fusion protein elicited strong delayed-type hypersensitivity responses in immunized mice. This investigation was undertaken to determine if the recombinant Ag2 protein, expressed as an Ag2-glutathione S-transferase (GST) fusion protein, or Ag2 cDNA would protect mice against lethal challenge with C. immitis. The recombinant Ag2-GST protein protected BALB/c mice against intraperitoneal challenge with 250 arthroconidia, as assessed by a decrease in fungal CFU in tissues. The Ag2-GST-immunized mice did not show, however, an increased survival during a 30-day period postinfection. By contrast, immunization of mice with Ag2 cDNA ligated into the pVR1012 plasmid engendered protection against intraperitoneal challenge with 2,500 arthroconidia and against pulmonary challenge with 50 arthroconidia. Vaccine efficacy paralleled the development of delayed-type hypersensitivity responses to C. immitis antigen. Whereas mice vaccinated with the recombinant Ag2-GST protein did not mount footpad hypersensitivity to C-ASWS or the recombinant Ag2-GST protein, mice vaccinated with the pVR1012-Ag2 construct mounted a strong footpad hypersensitivity and their spleen cells secreted gamma interferon upon in vitro stimulation with the Ag2-containing C-ASWS extract. This is the first investigation to show that genetic immunization can protect against lethal challenge with C. immitis.

Emerging infectious diseases and amphibian population declines

We review recent research on the pathology, ecology, and biogeography of two emerging infectious wildlife diseases, chytridiomycosis and ranaviral disease, in the context of host-parasite population biology. We examine the role of these diseases in the global decline of amphibian populations and propose hypotheses for the origins and impact of these panzootics. Finally, we discuss emerging infectious diseases as a global threat to wildlife populations.

Protection against lethal murine coccidioidomycosis by a soluble vaccine from spherules

The formaldehyde-killed, whole-spherule vaccine, which is protective against lethal challenge of laboratory animals with Coccidioides immitis, was fractionated. It yielded a soluble, multicomponent, subcellular fraction termed the 27K vaccine. This vaccine, when it was accompanied by adjuvant, protected mice against lethal intranasal and intravenous challenge with C. immitis.

Production of tumor necrosis factor alpha, interleukin-1 alpha, and interleukin-6 during murine coccidioidomycosis

The proinflammatory cytokines tumor necrosis factor alpha (TNF-alpha), interleukin-1 alpha (IL-1 alpha), and interleukin-6 (IL-6) were induced in mice infected with Coccidioides immitis. Analyses of the cytokine profiles of two inbred mouse strains which differ in their susceptibility to pulmonary challenge with C. immitis revealed higher levels of IL-6 in lungs from DBA/2 mice (resistant strain) than in those from BALB/c mice (susceptible strain) beginning at day 6 and continuing through day 15 postinfection. Spleen cells from both mouse strains secreted TNF-alpha, IL-1 alpha, and IL-6 in vitro in response to stimulation with killed spherules but differed in that spleen cells from the resistant strain produced increased levels of these cytokines earlier after pulmonary challenge and at increased levels throughout the course of the disease.

Cytokine induction in human coccidioidomycosis

To investigate the immune response to human infection with the fungus Coccidioides immitis, we measured cytokine production from peripheral blood mononuclear cells (PBMC) and plastic-adherent monocytes/macrophages (Mphi) isolated from healthy subjects who were skin test positive to spherulin, healthy subjects who were skin test negative, and patients with active coccidioidomycosis. PBMC and Mphi from all these donor groups secreted increased levels of tumor necrosis factor alpha, interleukin-1 beta, and interleukin-6 in response to stimulation with formalin-killed spherules (FKS), as measured by enzyme-linked immunosorbent assays. Viable C. immitis spherules also stimulated PBMC and Mphi from healthy subjects and patients to secrete tumor necrosis factor alpha, interleukin-1 beta, and interleukin-6, although at levels lower than those induced by FKS. The production of these acute inflammatory cytokines may contribute to the immunopathogenesis of active coccidioidomycosis and could account for the toxicity of the FKS vaccine in humans.