B. burgdorferi BamA, BB0324, and BB0028 co-immunoprecipitate (co-IP). Cultures of B. burgdorferi strain B31-MI (2 × 1010 organisms per sample) were washed and solubilized, and the protein-containing cell lysate was used for co-IP experiments using anti-Thio, anti-BamA, anti-BB0324, and anti-BB0028 polyclonal antibodies (indicated above panels). Equal amounts of each co-IP elution were subjected to SDS-PAGE and immunoblot analysis using antisera generated against BamA, BB0324, and BB0028 (indicated at left of each panel). To illustrate specificity of the BamA-BB0324-BB0028 interaction, elutions were also immunoblotted with antibodies against an unrelated subsurface OM lipoprotein, Lp6.6 (bottom panel). Anti-Thio antibodies were used in the co-IP experiments as a negative control (left lane of each panel). Additionally, whole-cell lysates (WCL) were included as positive controls for the immunoblot procedure (right panels).