Infection with the genotype ΔdbpAB/dbpA' elicited an anti-DbpA response 2.6-fold stronger than inoculation with the ΔdbpAB/dbpAB spirochetes at 2 weeks (P = 0.02), but both phenotypes induced similar responses at 4 months (P = 1.0), indicating that increased DbpA synthesis triggers a faster humoral response. Here, YBX3 is linked to infection.