Development of an Anti-Elicitin Antibody-Based Immunohistochemical Assay for Diagnosis of XXXX .

@entity1 @entity25276 @entity281 @entity3795 @entity526
@entity25276 is an emerging and life-threatening infectious disease of @entity1 and animals living in tropical and subtropical countries and is caused by the fungus-like organism Pythium insidiosum. Antifungals are ineffective against this pathogen. Most @entity1 undergo surgical removal of the infected organ, and many die from advanced @entity281 . Early and accurate diagnosis leads to prompt management and promotes better prognosis for affected @entity1 . Immunohistochemical assays (IHCs) have been developed using rabbit antibodies raised against P. insidiosum crude extract, i.e., culture filtrate antigen ( @entity3795 ), for the histodiagnosis of @entity25276 , but cross-reactivity with pathogenic fungi compromises the diagnostic performance of the IHC. Therefore, there is a need to improve detection specificity. Recently, the elicitin protein, ELI025, was identified in P. insidiosum, but it was not identified in other @entity1 pathogens, including true fungi. The ELI025-encoding gene was successfully cloned and expressed as a recombinant protein in @entity526 . This study aims to develop a new IHC using the rabbit anti-ELI025 antibody (anti-ELI) and to compare its performance with the previously reported anti-CFA-based IHC. Thirty-eight P. insidiosum histological sections stained positive by anti-ELI-based and anti-CFA-based IHCs indicating 100% detection sensitivity for the two assays. The anti-ELI antibody stained negative for all 49 negative-control sections indicating 100% detection specificity. In contrast, the anti-CFA antibody stained positive for one of the 49 negative controls (a slide prepared from Fusarium-infected tissue) indicating 98% detection specificity. In conclusion, the anti-ELI based IHC is sensitive and specific for the histodiagnosis of @entity25276 and is an improvement over the anti-CFA-based assay.
