Maternal transfer of oral vaccine induced anti-OspA antibodies protects <i>Peromyscus</i> spp. from tick-transmitted <i>Borrelia burgdorferi</i>

The efficacy and duration of passive immunity protection depend on maternal antibody levels and transfer efficiency. We investigated whether oral vaccination of <i>Peromyscus leucopus</i> dams with recombinant outer surface protein A (OspA)-expressing <i>Escherichia coli</i> could induce maternal transfer of anti-OspA antibodies and protect pups from <i>Borrelia burgdorferi</i> 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 <i>Ixodes scapularis</i>-transmitted <i>B. burgdorferi</i> at ~4 weeks of age. Anti-OspA IgG was quantified in dams and pups, and anti<i>-B</i>. <i>burgdorferi</i> IgG was quantified in pups. <i>B. burgdorferi</i> burden was assessed by <i>flaB</i> quantitative PCR in pups' tissues ~4 weeks after tick challenge, and viability of <i>B. burgdorferi</i> was assessed by culture of the heart tissue. <i>P. leucopus</i> pups born to dams vaccinated until breeding had low serologic anti-OspA antibody and were not protected from tick-transmitted <i>B. burgdorferi</i> infection. However, when dams' vaccination extended until parturition and until pups were 2 weeks old, significant anti-OspA antibody transfer and protection from <i>B. burgdorferi</i> infection occurred. This was evidenced by the absence of antibody to <i>B. burgdorferi</i> PepVF, absence of <i>B. burgdorferi flaB</i> DNA in heart and bladder tissues, and absence of <i>flaB</i> in culture from heart tissues from pups euthanized >9 weeks after birth. We show that the transfer of anti-OspA antibodies from vaccinated <i>P. leucopus</i> dams to offspring prevents tick transmission and infection dynamics of <i>B. burgdorferi</i> in the major reservoir host of this spirochete in the USA.IMPORTANCEThis study contributes to our understanding of how interventions based in reservoir-targeted outer surface protein A vaccines designed to block transmission of <i>B. burgdorferi</i> from infected <i>Ixodes scapularis</i> ticks may disrupt the enzootic cycle of this spirochete and reduce incidence of Lyme disease.