Demonstration of OspC Type Diversity in Invasive Human Lyme Disease Isolates and Identification of Previously Uncharacterized Epitopes That Define the Specificity of the OspC Murine Antibody Response

Abstract

Outer surface protein C (OspC) of the Lyme disease spirochetes is an important virulence factor that has potential utility for vaccine development. Of the 21 OspC types that have been identified, it has been postulated that types A, B, I, and K are specifically associated with invasive infections. Through an analysis of isolates collected from patients in Maryland we found that OspC types C, D, and N are also associated with invasive infections. This observation suggests that there is greater diversity in the group of OspC types associated with invasive infection than has been previously suggested. Detailed knowledge of the antigenic structure of OspC is essential for vaccine development. To determine if the antibody response to OspC is type specific, recombinant proteins of several different OspC types were immunoblotted and screened with sera from mice infected with isolates having known OspC types. These analyses revealed a high degree of specificity in the antibody response and suggested that the immunodominant epitopes of OspC reside in the variable domains of the protein. To localize these epitopes, OspC fragments were generated and screened with serum collected from infected mice. These analyses led to identification of previously uncharacterized epitopes that define the type specificity of the OspC antibody response. These analyses provide important insight into the antigenic structure of OspC and also provide a basis for understanding the variable nature of the antibody response to this important virulence factor of the Lyme disease spirochetes.

Construction and analysis of variants of a polyvalent Lyme disease vaccine: Approaches for improving the immune response to chimeric vaccinogens

“…The exclusive use of protective epitope sequences reduces the potential for misdirection of the response to irrelevant epitopes. In the context of OspC, this is particularly important as vaccination with full length r-OspC elicits immune responses to conserved domains that are not presented by the bacteria during infection [33,37,38]. In this study, we extend our efforts to develop and optimize a recombinant, polyvalent, chimeric OspC vaccinogen.…”

“…Recombinant full length OspC proteins of types A, B, K and D (minus the leader peptides) were generated as previously described, using a PCR based approach and ligase-independent cloning (LIC) methodologies with the pET-32 Ek/LIC vector (Novagen) [17,33]. The DNA sequences of these and all other constructs described in this report were confirmed (MWG Biotech).…”

“…Since the OspC sequence varies by an average of 35% between types, a broadly protective vaccine will have to be designed to incorporate multiple, type-specific epitopes [32,33]. Towards this goal, we have begun identifying the immunodominant linear epitopes of diverse OspC types.…”

“…Towards this goal, we have begun identifying the immunodominant linear epitopes of diverse OspC types. To date, these epitopes have been identified for OspC types A, B, K, and D, and the epitopes have been incorporated into a tetravalent chimeric vaccinogen [17,33,34]. This construct, designated as the ABKD vaccinogen, elicited an antibody response against each of the component epitopes, and those antibodies were bactericidal in a complement-dependent manner [17].…”

Biology of Infection with Borrelia burgdorferi

“…The OspC types of human clinical isolates have also been correlated with invasive and non-invasive phenotypes [128,131]. However, similar studies demonstrated greater diversity among invasive types than previously recognized, calling into question any causative effect of OspC sequence on invasion [130,132]. Carefully controlling for variables other than OspC has not been possible in such studies, since additional genome components of these isolates also differ.…”