Screening, preparation and identification of a broad-spectrum monoclonal antibody against Streptococcus pneumoniae surface protein A

Abstract

Objective To screen and prepare a broad-spectrum monoclonal antibody against Streptococcus pneumoniae (S.pneumoniae) surface protein A (PspA) and to evaluate its potential in clinical practice. Methods Hybridoma cells were screened and inoculated into the abdominal cavities of BALB/c mice to prepare antibodies in ascites. Monoclonal antibodies were obtained by ammonium sulfate precipitation and protein A affinity chromatography and then identified by SDS-PAGE and Western blot. Their specificity, isoforms and killing activities in vitro were analyzed. Results A broad-spectrum monoclonal antibody that recognized PspA subclasses 2, 3 and 4 was obtained. Its in vitro killing rate against S. pneumoniae reached 40.3%. Conclusions A broad-spectrum monoclonal antibody that could specifically bind to PspA was successfully prepared with a strong in vitro killing activity. This study provided reference for clinical diagnosis of S. pneumoniae-related diseases, quality assessment of S. pneumoniae vaccines and further research on monoclonal antibody therapeutics. Key words: Streptococcus pneumoniae; Streptococcus pneumoniae surface protein A (PspA); Monoclonal antibody