Epitope profiling of monoclonal antibodies to the immunodominant antigen BmGPI12 of the human pathogen Babesia microti

Abstract

The significant rise in the number of tick-borne diseases represents a major threat to public health worldwide. One such emerging disease is human babesiosis, which is caused by several protozoan parasites of the Babesia genus of which B. microti is responsible for most clinical cases reported to date. Recent studies have shown that during its intraerythrocytic life cycle, B. microti exports several antigens into the mammalian host using a novel vesicular-mediated secretion mechanism. One of these secreted proteins is the immunodominant antigen BmGPI12, which has been demonstrated to be a reliable biomarker of active B. microti infection. The major immunogenic determinants of this antigen remain unknown. Here we provide a comprehensive molecular and serological characterization of a set of eighteen monoclonal antibodies developed against BmGPI12 and a detailed profile of their binding specificity and suitability in the detection of active B. microti infection. Serological profiling and competition assays using synthetic peptides identified five unique epitopes on the surface of BmGPI12 which are recognized by a set of eight monoclonal antibodies. ELISA-based antigen detection assays identified five antibody combinations that specifically detect the secreted form of BmGPI12 in plasma samples from B. microti-infected mice and humans but not from other Babesia species or P. falciparum.

A Set of Diagnostic Tests for Detection of ActiveBabesia duncaniInfection

“…Immunodetection of BdV234 and BdV38--Polyclonal antibodies raised in rabbits (Cocalico Biologicals, Inc., PA) against the indicated B. duncani proteins were purified and used for the immunodetection analysis as described in detail (32). Briefly, supernatant (S), hemolysate (H), and parasite pellet (P) fractions collected either from B. duncani in vitro culture in hRBC (18% parasitemia) or B. duncani infected (24% parasitemia) or uninfected mRBCs were mixed with 4X Laemmli sample buffer (3:1 ratio), boiled at 80°C for 5 min and separated on 4-20% Mini-protean gels (Bio-Rad, P4568093).…”

“…Immunofluorescence assay (IFA)--Immunofluorescence assay was performed as reported previously (30,32) and described briefly in the supplementary methods.…”

Novel computational and drug design strategies for inhibition of monkeypox virus and Babesia microti: molecular docking, molecular dynamic simulation and drug design approach by natural compounds

“…Human babesiosis is a newly recognized tick-borne infection that is caused by an intraerythrocytic protozoan species belonging to the genus Babesia ( Chand et al, 2022 ). In recent decades, the epidemiology of human babesiosis has shifted from a few isolated cases to the emergence of outbreaks in the northeastern and midwestern United States, and research has shown that human babesiosis develops within the red blood cells of humans and small rodents ( Tanowitz and Weiss, 2009 ).…”