Identification of a Novel 74-Kilodalton Immunodominant Antigen of Pythium insidiosum Recognized by Sera from Human Patients with Pythiosis

Abstract

The oomycetous, fungus-like, aquatic organism Pythium insidiosum is the etiologic agent of pythiosis, a life-threatening infectious disease of humans and animals that has been increasingly reported from tropical, subtropical, and temperate countries. Human pythiosis is endemic in Thailand, and most patients present with arteritis, leading to limb amputation and/or death, or cornea ulcer, leading to enucleation. Diagnosis of pythiosis is time-consuming and difficult. Radical surgery is the main treatment for pythiosis because conventional antifungal drugs are ineffective. The aims of this study were to evaluate the use of Western blotting for diagnosis of human pythiosis, to identify specific immunodominant antigens of P. insidiosum, and to increase understanding of humoral immune responses against the pathogen. We performed Western blot analysis on 16 P. insidiosum isolates using 12 pythiosis serum samples. These specimens were derived from human patients with pythiosis who had different forms of infection and lived in different geographic areas throughout Thailand. We have identified a 74-kDa immunodominant antigen in all P. insidiosum isolates tested. The 74-kDa antigen was also recognized by sera from all patients with pythiosis but not by control sera from healthy individuals, patients with thalassemia, and patients with various infectious diseases, indicating that Western blot analysis could facilitate diagnosis of pythiosis. Therefore, the 74-kDa antigen is a potential target for developing rapid serodiagnostic tests as well as a therapeutic vaccine for pythiosis. These advances could lead to early diagnosis and effective treatment, crucial factors for better prognosis for patients with pythiosis.

Development of an Immunochromatographic Test for Rapid Serodiagnosis of Human Pythiosis

“…Some serodiagnostic tests have been developed to facilitate the early diagnosis of pythiosis (4, 6, 7, 13-15, 18, 25). In-house enzymelinked immunosorbent and Western blot assays show high degrees of sensitivity and specificity for the diagnosis of pythiosis (6,7,13). However, the tests require skilled personnel, stable and reproducible reagents, expensive equipment, and long turnaround times.…”

Proteínas imunorreativas de Conidiobolus lamprauges isoladas de ovinos infectados naturalmente

“…Houve diferença no padrão de reconhecimento entre os casos rinofaciais e rinofaríngeos da doença. A variação na resposta imune humoral observada pode estar relacionada à virulência da cepa, à fase de infecção e à cronicidade da doença para o desencadeamento de uma resposta imune do hospedeiro (Krajaejun et al 2006, Zapata et al 2012.…”

“…Portanto, a identificação e caracterização das mesmas podem contribuir para o entendimento dos mecanismos de patogenicidade nos casos da conidiobolomicose ovina, bem como na utilização para diagnósticos sorológicos ou como candidatos a vacinas. Estudos conduzidos em fungos patogênicos de importância biomédica já permitiram obter importantes informações sobre proteínas imunogênicas com papel fundamental no processo de invasão, sobrevivência no hospedeiro e como possíveis candidatos a vacina (Camargo et al 1989, Krajaejun et al 2006, Chindamporn et al 2009, Perenha-Viana et al 2012, Magalhães et al 2012.…”

Pythium aphanidermatum Infection following Combat Trauma

“…Pythium species originally belonged to the oomycetous kingdom of fungi but were reclassified to the kingdom Stramenopila, phylum Oomycota, class Oomycetes, and family Pythiaceae. These organisms are typically found in tropical and subtropical regions and are described as a group of aquatic, parafungal microbes with hyaline elements that form motile spores (2,8,9,10,11,13,17,19). Pythium is often confused with mucoraceous fungi, as the sparsely septate, hyaline hyphalike elements of Pythium species resemble the sparsely septate, hyaline hyphae seen in the Mucorales (11,13).…”