Horn, E. J. | bioRxiv Science

bioRxiv2025

Protective efficacy of mutant strains of Borrelia burgdorferi as potential reservoir host-targeted biologics against Lyme disease

Lyme disease (LD), caused by Borrelia burgdorferi (Bb), is the most common vector-borne disease in the United States. Novel strategies to control transmission of Bb to humans via ticks are critical for prevention of LD. One such strategy is to leverage non-infectious mutant strains of Bb for pathogen-derived biologics to block Bb transmission during the natural infectious cycle. Deletion of Borrelia host-adaptation Regulator ({Delta}badR) and replacement of 8 conserved residues with alanines in Carbon Storage Regulator A of Bb (8S) resulted in mutants, with upregulation of RpoS and several immunogenic lipoproteins, that were incapable of colonization in C3H/HeN mice. Intradermal vaccination of mice with the live mutant strains resulted in significant anti-borrelial antibody responses and a reduction in Bb acquisition by naive Ixodes scapularis larvae following needle challenge with Bb B31-A3. While vaccination with {Delta}badR mutant conferred significant reduction in the percentage of infected mice, ML23 and 8S mutants conferred variable levels of protection. Comparative proteomic analysis of Purified Borrelial Lipoproteins (PBLs) from parental and mutant strains revealed similar and unique antigenic components. Infection derived mouse serum and serum from Lyme disease patients exhibited reactivity to lysates and PBLs from these mutants. Immunization with PBLs from B31-A3 and 8S strains conferred significant protection against challenge with Bb infected nymphs, underscoring the utility of PBLs as protective formulations. Overall, non-infectious mutant strains, or their lipoproteins, can be exploited as biologics to block the acquisition of Bb by naive larvae from reservoir hosts, disrupting the enzootic transmission cycle of the agent of Lyme disease.

microbiology↗

bioRxiv2023

Single-tier point-of-care serodiagnosis of Lyme disease

Point-of-care (POC) serological testing provides actionable information for several difficult to diagnose illnesses, empowering distributed health systems. Accessible and adaptable diagnostic platforms that can assay the repertoire of antibodies formed against pathogens are essential to drive early detection and improve patient outcomes. Here, we report a POC serologic test for Lyme disease (LD), leveraging synthetic peptides tuned to be highly specific to the LD antibody repertoire across patients and compatible with a paper-based platform for rapid, reliable, and cost-effective diagnosis. A subset of antigenic epitopes conserved across Borrelia burgdorferi genospecies and targeted by IgG and IgM antibodies, were selected based on their seroreactivity to develop a multiplexed panel for a single-step measurement of combined IgM and IgG antibodies from LD patient sera. Multiple peptide epitopes, when combined synergistically using a machine learning-based diagnostic model, yielded a high sensitivity without any loss in specificity. We blindly tested the platform with samples from the U.S. Centers for Disease Control & Prevention (CDC) LD repository and achieved a sensitivity and specificity matching the lab-based two-tier results with a single POC test, correctly discriminating cross-reactive look-alike diseases. This computational LD diagnostic test can potentially replace the cumbersome two-tier testing paradigm, improving diagnosis and enabling earlier effective treatment of LD patients while also facilitating immune monitoring and surveillance of the disease in the community.

bioengineering↗