American Journal of Microbiological Research. 2014, 2(6), 174-177DOI:
Abstract: Streptococcus pneumoniae serotype 19F is one of major pneumococcal serotypes responsible for pneumococcal invasive disease in children less than 5 years worldwide. Pneumococcal conjugate vaccines (PCVs) were developed through chemical coupling of capsular polysaccharides of pneumococci to immunogenic carrier proteins and World Health Organization recommends the inclusion of these vaccines in national immunization programs for children. However, costly manufacture of PCVs can prevent their implementation in developing countries. This issue can be addressed by construction of protein based vaccines against pneumococci. Cell surface proteins are key factors in infectious processes of pathogens and are attractive as vaccine candidates. LPxTG motif containing proteins, lipoproteins, and choline binding proteins are among main groups of pneumococcal surface proteins. In this study, therefore, we aim to identify suitable candidates among these proteins for development of proteinaceous vaccines against S. pneumoniae serotype 19F infection using bioinformatic tools. These proteins were then identified in proteome data of S. pneumoniae 19F-14 through BLAST with LPxTG, lipobox consensus motifs, and the choline binding protein consensus sequence. PRED-LIPO online tool was used to confirm the presence of lipoprotein specific signal peptide. The cellular location of the proteins was analyzed with PSORTb v.3.0. Vaxijen v.2.0 was used to evaluate the protein antigenicity. BLAST against human proteome was done to remove the possibility for autoimmunity induction by the proteins. Moreover, the presence of homolog proteins in other pneumococcal serotype 19F strains including S. pneumoniae A026, S. pneumoniae G54, and S. pneumoniae ST556 were investigated. Our analysis revealed that cell wall surface anchor family protein ( YP_002741626.1), D-alanyl-D-alanyl-carboxy peptidase, surface protein PspC, and choline binding protein D are promising candidates for development of protein based vaccines against S. pneumoniae serotype 19F infection.