Journal article
Conformational Dependence and Conservation of an Immunodominant Epitope within the Babesia equi Erythrocyte-Stage Surface Protein Equi Merozoite Antigen 1
Clinical and diagnostic laboratory immunology, Vol.9(6), pp.1301-1306
11/2002
Handle:
https://hdl.handle.net/2376/103681
PMCID: PMC130086
PMID: 12414764
Abstract
Equi merozoite antigen 1 (EMA-1) is an immunodominant
Babesia equi
erythrocyte-stage surface protein. A competitive enzyme-linked immunosorbent assay (ELISA), based on inhibition of monoclonal antibody (MAb) 36/133.97 binding to recombinant EMA-1 by equine anti-
B. equi
antibodies, detects horses infected with strains present throughout the world. The objectives of this study were to define the epitope bound by MAb 36/133.97 and quantify the amino acid conservation of EMA-1, including the region containing the epitope bound by MAb 36/133.97. The alignment of the deduced amino acid sequence of full-length EMA-1 (Florida isolate) with 15 EMA-1 sequences from geographically distinct isolates showed 82.8 to 99.6% identities (median, 98.5%) and 90.5 to 99.6% similarities (median, 98.9%) between sequences. Full-length and truncated recombinant EMA-1 proteins were expressed and tested for their reactivities with MAb 36/133.97. Binding required the presence of amino acids on both N- and C-terminal regions of a truncated peptide (EMA-1.2) containing amino acids 1 to 98 of EMA-1. This result indicated that the epitope defined by MAb 36/133.97 is dependent on conformation. Sera from persistently infected horses inhibited the binding of MAb 36/133.97 to EMA-1.2 in a competitive ELISA, indicating that equine antibodies which inhibit binding of MAb 36/133.97 also recognize epitopes in the same region (the first 98 residues). Within this region, the deduced amino acid sequences had 85.7 to 100% identities (median, 99.0%), with similarities of 94.9 to 100% (median, 100%). Therefore, the region which binds to both MAb 36/133.97 and inhibiting equine antibodies has a median amino acid identity of 99.0% and a similarity of 100%. These data provide a molecular basis for the use of both EMA-1 and MAb 36/133.97 for the detection of antibodies against
B. equi
.
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Details
- Title
- Conformational Dependence and Conservation of an Immunodominant Epitope within the Babesia equi Erythrocyte-Stage Surface Protein Equi Merozoite Antigen 1
- Creators
- Cristina W Cunha - Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington 99164-7040Lowell S Kappmeyer - Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington 99164-7040Travis C McGuire - Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington 99164-7040Odir A Dellagostin - Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington 99164-7040Donald P Knowles - Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington 99164-7040
- Publication Details
- Clinical and diagnostic laboratory immunology, Vol.9(6), pp.1301-1306
- Academic Unit
- Veterinary Microbiology and Pathology, Department of
- Publisher
- American Society for Microbiology
- Identifiers
- 99900546622501842
- Language
- English
- Resource Type
- Journal article