serotype alternative phenomenon has stimulated interest in developing vaccine methods aimed at preventing pneumococcal disease in a non serotype limited way. A number of pneumococcal proteins that function as virulence facets have been identified and characterized as potential vaccine targets for inclusion in a general pneumococcal vaccine. A number of these virulence factors, including Gemcitabine Antimetabolites inhibitor PsaA, PpmA, and PspA, have already been proved to be cell wall linked proteins expressed by all strains of S. pneumoniae examined so far. The genes for PsaA, PpmA, and PspA and their corresponding proteins have each been recognized in multiple pneumococcal strains. From these studies, the typical observation was made that PsaA and PpmA are highly conserved, although PspA is relatively more variable at the DNA and protein sequence levels, among strains. We recently reported that immunization of rats with PsaA was only slightly protective against lethal endemic pneumococcal disease and that this somewhat minimal vaccine efficacy was correlated with inaccessibility of antibodies to PsaA at first glance of an intact encapsulated S. pneumoniae type 3 strain. We initiated today’s studies to increase Cholangiocarcinoma our knowledge of the partnership between accessibility to antibodies of potential vaccine targets on a diversified panel of pneumococcal strains and capability to elicit protective antibodies. We describe the availability of the cell wall linked proteins PsaA, PpmA, and PspA in 12 pneumococcal strains. We also assess the ability of active immunization with recombinant forms of PsaA, PpmA, or PspA, or passive immunization with polyclonal antisera raised against these proteins, to guard mice against lethal systemic pneumococcal disease. The effects of our results for pneumococcal vaccine design centered on highly protected Bicalutamide Casodex surface proteins are discussed. 6 to 8 week-old BALB/c rats were housed under certain pathogen free conditions and given food and water ad libitum. The rats were obtained from Taconic Farms, Germantown, D. B. The Case Western Reserve College Institutional Animal Care and Use Committee approved all animal experiments. Escherichia coli DH5 was used as the host for routine plasmid cloning. Recombinant proteins were expressed in E. coli BL21 / pLysS. Elizabeth. coli were cultured in Luria broth supplemented with antibiotics. Controversial S. pneumoniae strain A66. 1 was used for problem experiments and as a way to obtain genomic DNA for PCR amplification experiments. Clinical isolates of S. pneumoniae, including serotypes responsible for many pneumococcal infections in the Usa, were chosen from a collection of around 10,000 independent isolates at the University Hospitals of Cleveland, Cleveland, and are shown in Table 1. S. pneumoniae were routinely produced on Trypticase soy agar plates supplemented with 50k-100k sheep blood or in Todd Hewitt broth supplemented with 0. 5% yeast extract.