To further characterize interaction of FH with microbial surfaces, similar binding inhibition assays were used with three non-homologous and structurally unrelated bacterial outer surface proteins: OspE, a 15 kDa protein from a Lyme borreliosis agent B. burgdorferi[18], FhbA, a 20 kDa protein from a relapsing fever spirochete B. hermsii[25], and Tuf, a 43 kDa protein from P. aeruginosa[20]. The gene discussed is FH; the disease is Lyme disease.