Different strategies for preparation of non-tagged rV270 protein and its efficacy against Yersinia pestis challenge.

Objective: LcrV is an important component for the development of a subunit vaccine against plague. To reduce immunosuppressive activity of LcrV, a recombinant LcrV variant lacking amino acids 271 to 326 (rV270) was prepared by different methods in this study.

Methods: A new strategy that produced non-tagged or authentic rV270 protein was designed by insertion of rV270-thrombin-hexahistidine fusion gene into the vector pET24a, or by insertion of hexahistidine-enterokinase-rV270 or hexahistitine-factor Xa-rV270 fusion gene into the vector pET32a.

[Evaluation of immunization protection efficacy of plague subunit vaccine].

Objective: To evaluate the protective efficacy of plague subunit vaccine, BALB/c mice, guinea pigs and rabbits were used in this study.

Methods: Groups of mice (10 per group), guinea pigs (14 per group) and rabbits (6 per group) were immunized with F1 + rV270 vaccine, EV76 vaccine and alum adjuvant by intramuscular route, respectively. Serum antibody titres of mice, guinea pigs and rabbits were determined by ELISA and the immunized animals were challenged with 10(6) CFU of Y.

[Study on the pathogen of plague in Sanjiangyuan area in Qinghai province].

Objective: To study the biological characteristics of Yersinia pestis and to develop prevention and control program on plague in Sanjiangyuan areas, Qinghai province.

Methods: To identify the biologic types and molecular biological features of Y.pestis isolated in Sanjiangyuan area from 1954-2007.

[A molecular epidemiological study on human plague fulminant epidemic in Qinghai, 2004].

Objective: To study the epidemiology of genotyping Yersinia pestis isolated in the fulminant epidemics of human plague in Qinghai province in 2004.

Methods: Primer pairs targeting the twenty-three different identified regions (DFRs) were designed to detect the presence or deletion of each DFR in 13 strains of Yersinia pestis isolated from the fulminant epidemic of human plague in Qinghai province in 2004.

Results: There were 4 genomovars, i.