Culture of Borrelia persica and its flagellar antigen in vitro.

Borrelia persica is a strain seen only in the Middle East and responsible for relapsing fever. These spirochetes are notable for multiphasic antigenic variation of polymorphic outer membrane lipoproteins, a phenomenon responsible for immune evasion. Diagnosis of the disease is a problem and requires a fixed antigen like the flagellar antigen. In vitro culture of B. persica was carried out for the first time and flagellar antigen was purified from culture. 10% SDS was added to the mixture to dissolve the cell wall and then the solution was sheared in an Omni mixer. Electron microscopy confirmed the purity of a 42 KDa periplasmic antigen as revealed by SDS-PAGE. Indirect haemagglutination kits were designed using the pure flagella and tested for cross reactivity with another relapsing fever spirochaete Borrelia microtii positive serum. The kit showed 98% sensitivity and 95% specificity.