From 2014.igem.org

Overview

The goal of this project is to create a simple, cheap, fast-acting, and effective diagnostic tool that can be used to determine whether or not an organism is infected with any disease, as long as the antibody and antigen are known and available. CAEV was determined to be a good starting point based on the economic value of goats worldwide.

First, in the lab, the capsid protein p28 of CAEV is ligated onto the N-terminal domain of BclA, and a ribosome binding site, a constitutive promoter, and a double terminator are added to this construct. Next, competent E. coli are transformed with this plasmid, producing bacteria that express the CAEV p28 surface antigen on an even layer on the surface of its plasma membrane.

On the farm, a blood sample is taken from a goat to be tested for CAEV. The sample is transported to the lab, where it is centrifuged to separate out the plasma. Once the plasma is isolated from the pellet of blood cells, it is combined with the genetically engineered E. coli in a 96-well plate up to a titer of 5000.

If the goat is infected with CAEV, then the p28 antibodies should be present in its plasma. If the antibody is present, it will agglutinate with the E. coli expressing BclA and CAEV p28 when combined and left to rest overnight. This allows us to determine whether or not a goat is infected based on the results of a simple agglutination assay.