# Maternal transfer of oral vaccine induced anti-OspA antibodies protects Peromyscus spp. from tick-transmitted Borrelia burgdorferi

## TL;DR

Oral vaccination of mother mice with OspA protects their offspring from tick-transmitted Lyme disease bacteria.

## Contribution

Demonstrates maternal transfer of anti-OspA antibodies can block Borrelia burgdorferi infection in offspring.

## Key findings

- Vaccinating dams until parturition and 2 weeks postpartum conferred protection to pups against B. burgdorferi.
- Pups showed no detectable B. burgdorferi DNA or viable spirochetes in heart and bladder tissues.
- Maternal vaccination timing significantly affects antibody transfer and infection prevention.

## Abstract

The efficacy and duration of passive immunity protection depend on maternal antibody levels and transfer efficiency. We investigated whether oral vaccination of Peromyscus leucopus dams with recombinant outer surface protein A (OspA)-expressing Escherichia coli could induce maternal transfer of anti-OspA antibodies and protect pups from Borrelia burgdorferi challenge. Dams were vaccinated until breeding pairs were created (i), until parturition (ii), and until pups were 2 weeks old (iii). Pups were challenged with nymphal Ixodes scapularis-transmitted B. burgdorferi at ~4 weeks of age. Anti-OspA IgG was quantified in dams and pups, and anti-B. burgdorferi IgG was quantified in pups. B. burgdorferi burden was assessed by flaB quantitative PCR in pups’ tissues ~4 weeks after tick challenge, and viability of B. burgdorferi was assessed by culture of the heart tissue. P. leucopus pups born to dams vaccinated until breeding had low serologic anti-OspA antibody and were not protected from tick-transmitted B. burgdorferi infection. However, when dams’ vaccination extended until parturition and until pups were 2 weeks old, significant anti-OspA antibody transfer and protection from B. burgdorferi infection occurred. This was evidenced by the absence of antibody to B. burgdorferi PepVF, absence of B. burgdorferi flaB DNA in heart and bladder tissues, and absence of flaB in culture from heart tissues from pups euthanized >9 weeks after birth. We show that the transfer of anti-OspA antibodies from vaccinated P. leucopus dams to offspring prevents tick transmission and infection dynamics of B. burgdorferi in the major reservoir host of this spirochete in the USA.

This study contributes to our understanding of how interventions based in reservoir-targeted outer surface protein A vaccines designed to block transmission of B. burgdorferi from infected Ixodes scapularis ticks may disrupt the enzootic cycle of this spirochete and reduce incidence of Lyme disease.