Immunochemical Characteristics and Functional Activity of Monoclonal Antibodies Obtained to the Recombinant Form of Pneumolysin

Abstract

Monoclonal antibodies (mAbs) of the IgG1 isotype obtained to the full-length recombinant pneumolysin (rPly) did not recognize or poorly recognized conformational epitopes of native pneumolysin in ELISA. At the same time, polyclonal antibodies (pAbs(rPly)) detected native pneumolysin in sandwich ELISA when they were used as capture and detecting antibodies simultaneously. All mAbs(rPly) inhibited erythrocyte hemolysis induced by native pneumolysin. The combined use of mAbs(rPly) did not reveal an increase in optical density in ELISA and an increase in inhibition hemolytic activity, which suggests that mAbs(rPly) are directed to the same or spatially closely located epitopes. pAbs(rPly) more effectively inhibited erythrocyte hemolysis than mAbs(rPly).

Keywords: inhibition of hemolytic activity; monoclonal antibodies; native pneumolysin; recombinant pneumolysin; sandwich ELISA.