Journal article
Dimorphic sequences of rap-1 genes encode B and CD4 + T helper lymphocyte epitopes in the Babesia bigemina rhoptry associated protein-1
Molecular and biochemical parasitology, Vol.81(1), pp.89-99
1996
Handle:
https://hdl.handle.net/2376/110325
PMID: 8892308
Abstract
The rhoptry-associated protein-1 (RAP-1) of
Babesia bigemina induces protective immune responses in cattle and contains neutralization-sensitive B cell epitopes. RAP-1 variants containing blocks of sequence dimorphism in the amino and carboxy terminal ends are encoded by four nonallelic genes in
B. bigemina. Epitopes recognized by RAP-1 specific monoclonal antibodies (MAbs) and bovine CD4
+ T cell clones were mapped to determine whether these epitopes are localized in the amino and carboxy terminal dimorphic regions. Four B cell epitopes, including a neutralization-sensitive epitope, required both the amino terminal variant type 1 (NT-1) and non-dimorphic sequences for conformation. Intrachain disulfide bonds were required for at least one of these epitopes, since reduction and alkylation of cysteine residues abolished MAb binding. A fifth B cell epitope was mapped to the carboxy terminal variant type 1 (CT-1). As expected, the neutralizing MAb and two other MAbs requiring NT-1 for epitope binding recognized only the two RAP-1 variants with the NT-1 sequence, while the MAb binding an epitope in CT-1 did not bind RAP-1 variants with CT-2. In contrast, the fourth MAb requiring NT-1 for binding recognized all
rap-1 gene products, indicating that dimorphic residues are not part of the epitope recognized by this MAb. Bovine CD4
+ T cell clones characterized previously as responding in a strain dependent fashion recognized at least one epitope in CT-1, and did not cross-react with CT-2. A second group of bovine CD4
+ T cell clones that responded to multiple parasite strains recognized an epitope in a non-dimorphic region of RAP-1. These data indicate that dimorphic regions of RAP-1 encode unique B and T helper lymphocyte epitopes and may be required for enhanced protective immune responses in cattle.
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Details
- Title
- Dimorphic sequences of rap-1 genes encode B and CD4 + T helper lymphocyte epitopes in the Babesia bigemina rhoptry associated protein-1
- Creators
- Isidro Hötzel - Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164-7040, USAWendy C Brown - Department of Veterinary Pathobiology, Texas A&M University, College Station, TX 77843, USATerry F McElwain - Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164-7040, USASergio D Rodríguez - Department of Veterinary Pathobiology, Texas A&M University, College Station, TX 77843, USAGuy H Palmer - Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164-7040, USA
- Publication Details
- Molecular and biochemical parasitology, Vol.81(1), pp.89-99
- Academic Unit
- Veterinary Microbiology and Pathology, Department of; Paul G. Allen School for Global Animal Health
- Publisher
- Elsevier B.V
- Identifiers
- 99900547163801842
- Language
- English
- Resource Type
- Journal article