Protective responses of an engineered PspA recombinant antigen against Streptococcus pneumoniae

In this study, we developed two immunogenic antigens based on recombinant PspA proteins that including the different antigenic regions of PspA from both two families. The cross-reactivity of antibodies elicited against two PspA proteins PspAB1-5 and PspA4ABC and their role in complement deposition with three strains of pneumococci were tested. The protective effects of developed anti-PspA antibodies in mice in intranasal and intraperitoneal challenges were evaluated using a strain from clade 2. Sera from immunized mice with PspAB1-5 in comparison with PspA4ABC was able to deposit more C3 complement component on surface of pneumococci bearing diverse PspA from both families 1 and 2, and immunized mice with the PspAB1-5 showed a higher protection than PspA4ABC in pneumococcal challenges.The obtained results from this study indicate that a PspA-based antigen composed of B region from all clades in addition to conserved domains, can provide a significant protection against multiple strains of S. pneumoniae and may overcome the limitation of polysaccharide vaccines.
Source: Biotechnology Reports - Category: Biotechnology Source Type: research