Researchers at IQFR have developed, in collaboration with other CIBERES research groups, a new microarray application for the detection in serum of antibodies specific against different pneumococcal serotypes

An important virulence factor of Streptococcus pneumoniae, pneumococcus, is its polysaccharidic capsule, as it allows bacterial evasion of the innate immune response by preventing complement activation and phagocytosis of the bacterium by immune system cells. To date, at least 99 different pneumococcal serotypes with different structures of the capsular polysaccharide (or CPS) have been identified. Anti-CPS IgG antibodies confer protection against S. pneumoniae, leading to clearance of the bacteria. However, the immunity conferred by these antibodies is strictly specific of the capsular serotype. Currently available pneumococcal vaccines, which are based on the use of CPSs from a selection of serotypes most frequently associated with serious diseases, provide coverage only against the included serotypes. However, the worldwide incidence of pneumococcal disease remains high and the frequency of infections caused by non-vaccine serotypes is increasing. Therefore, it is important to know against which pneumococcal serotypes the population is protected. This is usually evaluated using an immunoenzymatic assay recommended in 2000 by the World Health Organization (WHO) for the detection and quantification in serum of IgG antibodies against the different S. pneumoniae CPSs.

María Asunción Campanero and Dolores Solís, IQFR researchers, have developed a new method to detect these antibodies, based on microarray printing of a CPS library of different serotypes. The advantages of this new application are to require significantly lower amounts of CPS and serum than the mentioned immunoenzymatic assay and to allow the simultaneous analysis of different sera samples as well as multiple CPS-serum interactions, thus reducing both time and cost of the assay. These peculiarities enhance its usefulness when sample volumes are limited and / or in studies covering numerous serum samples, such as population studies to determine the specific contribution of different serotypes to ongoing pneumococcal diseases or those intended to assess the impact of vaccination strategies.

Reference:

Development and Evaluation of a Microarray Platform for Detection of Serum Antibodies Against Streptococcus pneumoniae Capsular Polysaccharides. Campanero-Rhodes MA, Lacoma A, Prat C, García E, Solís D. Anal. Chem. 2020, 92:7437–7443, May 14. https://doi.org/10.1021/acs.analchem.0c01009. [Epubahead of print] PMID: 32407098