Premium
Defining the complement C3 binding site and the antigenic region of Haemonchus contortus GAPDH
Author(s) -
Rajan Parvathy,
Mishra Prasanta K. K.,
Joshi Paritosh
Publication year - 2019
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.12611
Subject(s) - haemonchus contortus , biology , glyceraldehyde 3 phosphate dehydrogenase , immunogenicity , antigen , biochemistry , complement system , microbiology and biotechnology , binding site , alternative complement pathway , enzyme , amino acid , immune system , dehydrogenase , immunology , helminths
Summary Haemonchus contortus is an economically important parasite that survives the host defense system by modulating the immune response. Glyceraldehyde‐3‐phosphate dehydrogenase ( GAPDH ) is secreted by the parasite and the host responds by producing anti‐enzyme antibodies. The enzyme inhibits complement cascade, an arm of the innate immunity, by binding to complement C3. In this study, the C3 binding site and the antigenic region of the enzyme were identified by generating short recombinant fragments and deleting a defined region of the enzyme. Using these proteins in ligand overlay and plate binding assay, the C3 binding region of GAPDH was localized within the 38 residues represented by 77‐114 amino acids whereas one of the antigenic regions was identified in between 77 and 171 amino acids. In addition, deletion of amino acids 77 to 171 from GAPDH (fragment AB ) also showed weak immunogenicity but lacked C3 binding activity. Fragment D comprising 95 residues (77‐171), had both the C3 binding activity as well as immunogenicity like the parent enzyme, also stimulated host peripheral blood mononuclear cells in vitro. This truncated GAPDH moiety was stable at refrigerated temperature for at least 12 weeks and appears as a promising new therapeutic tool considering its longer shelf life as compared to the parent protein.