Recombinant antigens of outer surface proteins (Osps) OspA, OspB, OspC, OspE, and OspF of Borrelia burgdorferi sensu stricto and of p41-G, an antigenic region of flagellin of this spirochete, were tested with human sera in class-specific and polyvalent enzyme-linked immunosorbent assays (ELISAs). In analyses for immunoglobulin M (IgM) antibodies, 18 (85.7%) of 21 serum samples from persons who had been diagnosed as having
Lyme borreliosis on the basis of the presence of erythema migrans reacted positively in ELISAs with one or more Osp antigens or the p41-G antigen. Eleven serum samples contained antibodies to OspC antigen, and of these, six also reacted to the p41-G antigen and to one or more of the other recombinant antigens. The remaining five serum samples reacted solely to OspC (n = 4) or to OspC plus OspA and OspE without reactivity to p41-G (n = 1). In analyses for IgG antibodies, seropositivity was comparable to that of IgM analyses and was marked by predominant reactivity to p41-G, OspC, and OspF. Similarly, all 21 serum samples were positive in polyvalent and class-specific ELISAs with whole-cell B. burgdorferi. Minor cross-reactivity was noted when sera from persons who had syphilis, periodontitis or other oral infections, or rheumatoid arthritis were tested with OspC, OspE, OspF, and p41-G. With relatively high degrees of specificity, ELISAs with recombinant antigens, particularly OspC and p41-G, can help to confirm B. burgdorferi infections.