The new method allows researchers to rapidly screen large numbers of pathogen proteins for their ability to prompt an immune response in a host. Proteins with that ability are good candidates for use in vaccines. The method will be especially valuable in the quest for vaccines against persistent diseases such as malaria, sleeping sickness and syphilis.
The new method starts with the pathogen’s DNA. Previous work by WSU scientists had determined the whole genome sequence of Anaplasma. By comparing that sequence with the genome sequences of better-known microbes, immunologist Wendy Brown and her team were able to pinpoint genes that code for proteins that stick out of the pathogen’s cell membrane. Brown reasoned that since those proteins are exposed on the surface of the cell, they should be visible to antibodies and immune system cells, and therefore could be a good way to target the pathogen.
Once the genes were isolated, Brown’s team made the proteins they coded for by using chemical ‘machinery’ derived from E. coli bacteria. They then purified each protein to get rid of any E. coli proteins that were present. They did that by using a chemical that would specifically bind to the Anaplasma proteins. Brown attached the chemical to tiny synthetic beads and then poured the protein mixture over the beads. Anaplasma proteins stuck to the beads, while E. coli proteins did not and were discarded. This purification step represented a big advance over other methods, which have been plagued by contamination with irrelevant proteins.
Using the new procedure, Brown’s team found T cells responded to about 20 proteins, including many that had never before been shown to stimulate a T cell response. The researchers are now testing whether any of these might form the basis for an effective vaccine against Anaplasma.
MEDICA.de; Source: Washington State University