Pneumococcal infections represent one of the main causes of morbility and mortality worldwide among children, with especial incidence in the developing countries. In our country, it has been detected during the last years an increase of some diseases associated to this bacterium, in spite of vaccination. However, the vaccination pressure is causing a displacement towards serotypes not covered by available vaccines. Therefore, the epidemiological surveillance is crucial to elucidate changes in infection profiles by the microorganism at the population level and the effectiveness of safeguards. Serological techniques offer a lot of chances for monitoring infection, providing in addition a tool for early diagnosis, which can help to make better decisions about treatments in patients, and to orientate measures to adopt concerning a population. In this project, we will develop a serological tool for the detection of pneumococcal infection in paediatric and adult patients, based on the Luminex technology, which allows to measure both early (IgM) and secondary immune response (IgG) to the pathogen, and to distinguish between infected people and healthy carriers. To do that, we will use as antigens a collection of 100 recombinant proteins of pneumococcus that we have in our laboratory, and which we have previously identified by proteomics. Such a technique would facilitate the epidemiological studies of vaccine effectiveness by its ease-of-use, and would make it easy to employ for serodiagnostic purpose in hospitals and primary care centers.
ACHIEVEMENTS:
From the recombinant proteins of the previous project, we have manufactured a protein array using Luminex microspheres, and we have tested a collection of sera from paediatric patients. We have obtained discrimination between infected and control groups by three proteins, although the sensitivity and specificity of this assay is lower than the protein chip on a glass surface. These results have been published in an article, as well as a book chapter describing the methodology is derived from this work.