A murine IgM monoclonal antibody binds an antigenic determinant in outer surface protein A, an immunodominant basic protein of the Lyme disease spirochete.
A hybridoma cell line formed by the fusion of the P3x63-Ag8.653 myeloma cell line with splenocytes from BALB/c mice immunized with Borrelia burgdorferi produced an IgM monoclonal antibody (mAb-11G1) with kappa-light chains which detected an antigenic determinant in a major spirochetal protein of m.w. approximately 31,000, also known as outer surface protein A (OSP-A). Apparent saturation was reached in approximately 35 min with 34 ng of mAb-11G1 binding to 5 X 10(7) spirochetes giving an estimated 4.8 X 10(2) IgM molecules per spirochete and thus a minimum of 480 binding sites per organism. Enzymatic digestion studies suggest that the antigenic determinant to mAb-11G1 is contained within the peptide chain of OSP-A as binding could be eliminated by treatment of the spirochetes with proteinase K, Pronase and pepsin (100 to 200 micrograms/ml of enzyme) but not by trypsin or bromelain treatment. Periodate oxidation as well as mixed and endoglycosidase treatment of the spirochetes did not alter the binding of mAb-11G1. Two-dimensional gel electrophoresis of whole spirochetal cell lysates disclosed that OSP-A is a heterogeneously charged basic protein with an apparent isoelectric point range from 8.5 to 9.0. Amino acid analysis of OSP-A showed a 10% lysine component which could provide the basic nature to the protein. OSP-A with the intact antigenic determinant for mAb-11G1 can be found in the urine of hamsters experimentally infected with B. burgdorferi.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000915:Antibody Affinity; D000918:Antibody Specificity; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology*; D001898:Borrelia / Q000276:immunology*; D025065:Borrelia burgdorferi; D006224:Cricetinae; D000939:Epitopes; D007526:Isoelectric Point; D008193:Lyme Disease / Q000382:microbiology*; D008297:Male; D008970:Molecular Weight
D000596:Amino Acids; D000911:Antibodies, Monoclonal; D001425:Bacterial Outer Membrane Proteins; D000939:Epitopes