Reactivity with a specific epitope of outer surface protein A predicts protection from infection with the Lyme disease spirochete, Borrelia burgdorferi

Abstract

The response to recombinant vaccines for Lyme disease was studied to determine serum antibody levels effective in protecting against tick-transmitted infection. Data presented here demonstrate a significant correlation between antibody to an epitope on outer surface protein A (OspA) and protection against infection with Borrelia burgdorferi in canines and mice. A competitive enzyme-linked immunosorbent assay was developed to measure antibody to a site on OspA, defined by monoclonal antibody LA-2. Comparison of LA-2 titers against infection of canines and mice following vaccination and challenge established a predicted value for LA-2 titers. The statistical relationship between serum antibody levels and protection was calculated by logistic regression analysis. The statistical model predicted that an LA-2 titer of 0.32 g equivalents (eq) per ml correlated to an 80% predicted probability of protection for both mice and dogs. This value was used to classify mice and dogs as to their protected status at the time of tick exposure. The LA-2 cutoff titer (0.32 g eq/ml) correctly classified all dogs (n ‫؍‬ 13) and mice (n ‫؍‬ 44) that failed to become infected. By contrast, 20 of 22 dogs and 28 of 31 mice with titers of less than 0.32 g eq/ml became infected. On the basis of these results, we conclude that an LA-2 titer is a reliable indicator of immune status for estimating immune protection following use of OspA-based vaccines for B. burgdorferi sensu stricto. MATERIALS AND METHODS Vaccines. Mice were vaccinated with four different OspA formulations as described previously (13). Briefly, the gene for OspA was isolated from B. burgdorferi sensu stricto ZS7, recombined, and expressed in Escherichia coli as either a whole lipidated protein or fused protein with NS-1 of influenza virus. The fusion protein is not lipidated. The codons for the N-terminal cysteine of OspA reside directly adjacent to the terminal codons of NS-1. Consequently, a primary amino group on the OspA moiety of the fusion protein is not available. The OspA gene of B. afzellii ACA-1 was also isolated and expressed, fused with NS-1, in E. coli. All but one of the experimental formulations for vaccination of mice were adsorbed to aluminum hydroxide gel. The ratio for adsorption was 1 mg of protein per 100 mg of aluminum hydroxide gel (13). Vaccination protocol. Outbred BALB/c and C3H/HeJ mice received three vaccinations at 2-week intervals. Serum samples were collected 1 week after the last vaccination and 1 week before challenge with infected Ixodes scapularis ticks. Details regarding the numbers of ticks used to challenge mice were reported previously (11). In an attempt to determine the effectiveness of the Lyme disease vaccine formulation in the normal regimen of canine vaccination, we incorporated the OspA vaccine into the normal, recommended canine schedule. Dogs were randomly assigned to one of four groups. At 8 to 9 weeks of age, all dogs received a dose of canine distemper-measles virus vaccine, modified live virus (MLV), and a dose of canine par...

Design and Development of a Novel Vaccine for Protection against Lyme Borreliosis

“…The obtained protection data also indicate that our design maintains the protective epitope characterized for OspA serotype 1 by the monoclonal antibody LA-2 [7] . An immune response to this epitope was shown to correlate with protection in a dog model of infection [18] and it was also shown in the LYMErix phase III clinical trial that the LA-2 equivalent antibody levels were lower in sera from breakthrough cases [52] . By focusing only on the C-terminal part of OspA, our LB-vaccine also possesses a higher molar ratio of potentially protective epitopes compared to a vaccine using the full-length OspA, which might be favorable since a low vaccine dose could still be effective in generating protective immunity.…”

“…Previous studies have shown that antibodies targeting the C-terminal part of OspA play a crucial role in protection [18] . Subsequently, it has been shown that a vaccine based on the C-terminal half of OspA from B. burgdorferi (constituting approximately 55% of the full-length protein) partially protected mice against a homologous challenge [19] .…”

Immunodominant Epitope in the C‐Terminus of a Variable Major Protein in Borrelia duttonii, an Agent of Tick‐Borne Relapsing Fever

“…Furthermore, the bactericidal antigen binding fragments (Fabs) H6831 and monoclonal antibody CB2 recognize the C-terminal fragment of B. burgdorferi OspB (4, 8, 12). Thus, the C-termini of the lipoproteins of Lyme disease borreliae Osps may stimulate targeting antibodies in the hosts (13,14,16,36). It is considered that the C-termini of the Vmp protein family of relapsing fever borreliae may be predominant B-cell epitopes for antibodies on these regions.…”

Anti-OspA DNA-Encoded Monoclonal Antibody Prevents Transmission of Spirochetes in Tick Challenge Providing Sterilizing Immunity in Mice

“…The Centers for Disease Control and Prevention has estimated that >300 000 Americans receive a diagnosis of Lyme disease yearly [1]. Antibodies raised against Borrelia outer surface protein A (OspA) block transmission of spirochetes from ticks to vertebrate hosts in animal models [2][3][4]. Based on the effectiveness of OspA-specific humoral immunity in these animal models, vaccines containing recombinant OspA of B. burgdorferi were developed to induce a similar antibody response in humans for the prevention of Lyme disease [5].…”