Expression of antigenic regions of a trypanosome variable surface glycoprotein in E. coli using Bal-31 nuclease digestion.

We have used the expression of a trypanosome variable surface glycoprotein (VSG) in E. coli to produce VSG serotype-specific antisera which have none of the cross-reacting specificities characteristic of antisera prepared against purified VSGs. This was accomplished by treating restriction fragments of VSG cDNAs with Bal-31 nuclease to facilitate expression of their open reading frames in the E. coli expression vector, pMR100 (4). The resultant VSG-beta-galactosidase fusion proteins possess various antigenic regions of the original VSG. This provides a rapid means for producing VSG-specific antisera for reagent use and has the capability of large scale production of antigen for immunological investigation.