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Identification of the complement 9‐binding protein in Setaria equina excretory‐secretory products
Author(s) -
AbdelLatif Mahmoud
Publication year - 2020
Publication title -
parasite immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 75
eISSN - 1365-3024
pISSN - 0141-9838
DOI - 10.1111/pim.12686
Subject(s) - complement system , biology , complement c1q , complement (music) , alternative complement pathway , factor h , complement factor i , biochemistry , immunology , microbiology and biotechnology , antibody , gene , complementation , phenotype
The current study aimed to detect the complement‐binding proteins in the excretory‐secretory (ES) products of adult filarial parasite Setaria equina (SeqES). Tests for complement activation pathways (CH 50 and APH 50 ) in normal human serum (NHS) after incubation with SeqES were performed. Quantitative detection of complement activation products like C3d and sC5b‐9 by ELISA in inulin‐activated NHS before and after addition of SeqES was estimated. Immunoblotting for 1D and 2D electrophoresed SeqES were performed for detection of C9‐binding protein. MALDI mass sequencing and multiple sequence alignment were performed for identification of the protein. The results showed an inhibitory effect of SeqES for complement activation pathways. This was confirmed by an obvious reduction in C3d and sC5b‐9 in inulin‐activated NHS. Immunoblotting showed the reaction of a protein at 21 kDa with human C9. The latter protein was identified as OV‐16 based on MALDI mass sequencing and multiple sequence alignment. In conclusion, S equina OV‐16 is the complement regulatory protein by its ability to bind C9 and inhibit the classical and alternative pathways of complement activation. This protein can be used as a target for therapeutic treatment or as an anti‐inflammatory agent in human diseases.