StudioG24SecL04Tpc5: Difference between revisions

Antigenic diversity enables the spirochete to escape host defense mechanisms and maintain infection. The variable regions of the lp28 -1 gene cassette extend this ability to VlsE. It has been postulated that infection induces sequence changes and thus alters the antigenic properties’ of VlsE. The generation of new antigens is thought to occur through the exchange of DNA cassettes by the process of recombination.  This recombination could potentially help spirochetes escape anti-body mediated attack. The Vlse gene cluster consists of the single VlsE and 15 silent cassettes upstream.  Unidirectional gene conversion events between the silent cassettes and VlsE gene generate new Vls variants. By producing a myriad of VlsE varaints that do not effectively bind to ant-VlsE antibodies elicited by previous versions of the protein VlsE evades immune destruction..<ref name="E">PMID:10553085</ref>

One of the invariable regions IR6, showed both the highest levels of antigenicity by the Hopps-Woods algorithm and amino acid seqence identify among Borrelia genospecies and strains. Thus it is the most immunodominate region and what allows for the persistent humoral response. Examination of IR6 by the immunoprecipitation with the rabbit anti-C6 antiserum and revealed that IR6 is exposed on VlsE surface. However, IR6 is not accessible to Ab on the outer membrane of the spirochete.