Pathogen escape from host immunity by a genome program for antigenic variation.

ABSTRACT: The vector-borne bacterium Borrelia hermsii, a relapsing fever agent, switches gene expression of a surface protein between different antigenic variants, thereby causing sequential waves of immune escape within hosts and increasing the likelihood of transmission. Analogous programmed systems of antigenic variation occur in African trypanosomes and Plasmodium falciparum. In these examples, switch rates to individual variants differ over a wide range. We studied how B. hermsii determines switch rates in two experimental infections: one where variants were identified by specific antisera and one based on identification by DNA sequence. Unexpressed loci of variant antigens copy into a single expression site at rates determined by extragenic features of silent loci rather than similarity betwee

SUBMITTER: Barbour AG 

PROVIDER: S-EPMC1635980 | biostudies-literature | 2006 Nov

REPOSITORIES: biostudies-literature