United Kingdom (UK)
Recombinant monoclonal antibody to trans-sialidase. Manufactured using AbAb’s Recombinant Platform with variable regions (i.e. specificity) from the hybridoma 13G9.
UniProt Accession Number of Target Protein: Q26966
Alternative Name(s) of Target: TS
Immunogen: 13G9 was prepared by immnuizing mice with recombinant TS (Δ1443TS), which is fully active but includes a deletion of a non-neutralizing epitope (speeds up production of neutralizing antibodies). The antibody was selected for by screening using a TS-inhibition assay.
Specificity: 13G9 is a neutralizing antibody which binds specifically and with high affinity (KD ~0.72 nM) to a conformational epitope on the Trypanosoma cruzi TS protein – the antibody binds to TS in such a way as to prevent the movement of Y119, whose mobility has a key role in the trans-glycosidase mechanism. Specificity of binding was deduced by the absence of reactivity against TS from the closely related Trypanosoma rangeli and Trypanosoma brucei. A Fab fragment of the antibody was generated by digestion with papain - the Fab fragment possesses lower inhibitory activity against T. cruzi TS (Fab IC50 ~1.6nM; full-length mAb IC50 ~56pM). Trypanosoma cruzi is a protozoan parasite which causes Chagas' disease (or American trypanosomiasis) and its protein TS is a glycosylphosphatidylinositol-anchored non-integral membrane protein and a virulence factor which is involved in host cell invasion/survival, as well as being actively shed in the bloodstream. TS performs a glyosyl-transfer reaction to convert host glycoconjugates into sialic acids (cannot perform de novo synthesis of sialic acids, which are important for life cycle and survival).
Application Notes: 13G9 can be used for IF with whole parasites which allows membrane localization of TS to be observed. The antibody can inhibit TS-mediated sialylation of the parasite via the transfer of sialic acid from the enivronment to the surface of the parasite. Cell invasion (a process in which TS plays a key role) is also inhibited by 13G9 and was shown to greatly reduce the number of T. cruzi-infected cells. Passive transfer of 13G9 to T. cruzi-infected mice provided protection against the delterious effects that TS has on the immune system and platelets. The 13G9 Fab fragment was also used to crystallize TS for structure studies and this allowed the binding to TS to be seen.
Antibody first published in:
Buschiazzo et al. Trypanosoma cruzi trans-sialidase in complex with a neutralizing antibody: structure/function studies towards the rational design of inhibitors. PLoS Pathog. 2012 Jan;8(1):e1002474. PMID:22241998
Note on publication:
Describes the production of 13G9 and functional and structural studies on th mAb.