Antigens of Pasteurella tularensis: Preparative Procedures

Abstract

Ether-water (EW) extraction of Pasteurella tularensis produced better antigens than five other chemical procedures. EW extracts produced from stationary-phase, liquid-grown, saline suspensions of strain SCHU S4 cells regularly induced agglutinin and precipitin formation in rabbits. Mice, guinea pigs, and monkeys also responded to EW extracts but with lower antibody levels. The use of strains of lower virulence, acetone-dried cells, organisms grown on a solid medium, and abbreviated extraction conditions all resulted in extracts with a diminished antigenicity, but logarithmicphase and stationary-phase cells yielded equivalent EW extracts. The use of adjuvant, hyperimmunization, and large doses of antigen increased the precipitin responses of rabbits without appreciably altering the agglutinin response. By the appropriate combination of centrifugal fractionation of EW extracts, use of adjuvant, and vaccination schedule, rabbit antisera with either predominantly agglutinating or precipitating activities were obtained.

Antigen from Francisella tularensis: nonidentity between determinants participating in cell-mediated and humoral reactions

“…DISCUSSION Antigen for immunoprecipitation was more efficiently extracted from F. tularensis cells by ether-water treatment than by phenol-water extraction. This is in accordance with immunoprecipitation studies on various extracts of F. tularensis (20). To take full advantage of the high sensitivity of ELISA, the specificity of the antigen prepared is important (18).…”

“…Accordingly, ether-water extraction is known to be an efficient way to release antigens (21,22,25,26). When compared by immunoprecipitation, this extraction procedure is better than several others, including phenol-water extraction (20). Ether-water extracts, however, have not previously been utilized in ELISA or the lymphocyte stimulation test.…”

Guidelines for the diagnosis of tick-borne bacterial diseases in Europe

“…Several biochemical tests have been described that allow differentiation of F. tularensis subspecies and biovars [117]. An agglutination assay in which specific sera are used has also been used for identification of F. tularensis , but does not allow identification of the biovar [155]. More accurate differentiation is best achieved with molecular biological techniques.…”

Comparison of Different PCR Approaches for Typing of Francisella tularensis Strains

“…Some of these values are low, but the combination of some of the PCR methods allow us to achieve DI of 0.8 to 0.9. These results can be considered excellent, especially if both the small area from which the Spanish isolates were recovered and previous information about typing tools for Francisella strains are taken into account (the DI observed for serologic methods is 0, as only one antigenic group has been described so far [3,12], and DNA methods have been unable to discriminate between F. novicida and F. tularensis [5]). On the other hand, the results in this study were clearly different from those reported by Vila et al (16), who found that the RAPD assay was less discriminating than rep-PCR methods for typing of the Acinetobacter calcoaceticus-A.…”

“…The correct identification of strains of F. tularensis can be verified by agglutination with specific antisera. However, since strains of Francisella have similar antigenic compositions (to date all of the isolates belong to a unique antigenic group), it is not possible to distinguish the different subspecies or types from each other by this method (12). Subspecies of F. tularensis have been differentiated by biochemical tests (10) and by using probes specific to the 16S rRNAs of each of the two main subspecies (4,14).…”