Anticorpos monoclonais Anti-Pneumolisina e anti-PspA de Pneumococo como marcadores em teste imunocrotográfico rápido para detecção de Streptococus Pneumoniae

Abstract

Streptococcus pneumonia is an important human pathogen, which causes invasive pneumococcal diseases including pneumonia, meningitis and bloodstream infections. Responsible for high rates of child morbidity and mortality, especially in developing countries. Early diagnosis is important to lead an appropriate treatment. Strip-based immunochromatographic tests, or dipstick tests are fast, cheap, have good specificity, simple interpretation and performance. Thus, they correspond to the great alternative to conventional tests, especially in developing countries. This kind of test intends to detect the presence or absence of target analytes, such as bacterial antigens. In this study, monoclonal antibodies and conjugation methods were evaluated with two colored markers: dyed colloidal microspheres with carboxyl groups on their surface and colloidal gold nanoparticles. Monoclonal antibodies chose for conjugation were anti-pneumolysin (Ply) and anti-pneumococcus surface protein A (PspA). Anti-Ply polyclonal sera and anti-whole cell pneumococcal vaccine (WCPV) were used as capture antibodies. The best results were obtained with colloidal gold nanoparticles, in which bacterial antigens were detected in bacterial 107 a 104 CFU/mL samples and culture supernatant of S. pneumoniae serotype 9V, one of the most prevalent serotypes. The results were obtained between 10-20 minutes. The assessed dipstick can be considered as a promising sensitive and fast detection tool for antigens of S. pneumoniae.