الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Pneumococcal surface protein A (PspA) is one of the major virulence factors expressed by almost all pneumococcal serotypes and was suggested to be a promising universal vaccine candidate for all pneumococcal sero-groups. Proline-rich (PR) domain presents in all PspA molecules and is thought to be conservative and cross-reactive domain.The present study aimed to prepare and evaluate the protective efficacy of recombinant PR region of PspA against clinical highly virulent isolate of S.pneumoniae 19F (SP19) in order to develop broad spectrum cross-protective vaccine. Here, we expressed and purified the proline-rich region (PR) of PspA and tested it as a recombinant vaccine against infection caused by a clinical isolate (SP) of Streptococcus pneumoniae serotype 19F. Our results showed that BALB/c mice immunized with recombinant proline-rich (rPR) region showed a significant higher antibody titre against rPR region compared to control non-immunized group. However, immunized mice or mice recived polyclonal antibodies against rPR region challenged via the intra-peritoneal route with a lethal dose of SP isolate showed no significant difference in survival compared to control nonimmunized group. These results suggested that, immunization of BALB/c mice with rPR region of PspA is not protective against infection caused by serotype 19F in a mouse model.