AN OSPA FRAME-SHIFT, IDENTIFIED FROM DNA IN LYME ARTHRITIS SYNOVIAL-FLUID, RESULTS IN AN OUTER SURFACE PROTEIN-A THAT DOES NOT BIND PROTECTIVE ANTIBODIES

Passive immunization with murine or human Abs to outer surface protein A (OspA) can protect mice against Borrelia burgdorferi, but OspA Abs elicited during natural infection in mice or humans are unable to clea r the spirochete from the infected host, To examine Ab binding by OspA during the course of human infection, we amplified the operon encodin g full-length ospA and ospB from synovial fluids of a patient with chr onic Lyme arthritis, the first such recoveries From human material, at four separate time points over 4.5 mo, and expressed OspA in Escheric hia coli, OspA mAbs that passively protected mice from infection did n ot bind one of the expressed OspAs, because of a deletion in ospA that resulted in a frame shift and premature stop codon near the carboxyl terminus, However, expressed OspA from a later synovial fluid sample d id not contain this deletion, Thus, although altered forms of OspA, wh ich potentially can influence host immune effectiveness, do occur in t he human host, they cannot be the only factors responsible for microbi al persistence.