ABSTRACT
Objective To construct a recombinant Bacillus Calmette-Guerin ( BCG ) vaccine strain, rBCG::Rv3478-pMV261, expressing the Rv3478 protein of Mycobacterium tuberculosis and to inves-tigate its immunogenicity.Methods The gene fragments encoding Rv3478 antigen were amplified by PCR and then respectively cloned into pMV261 and pET-28a vectors to construct the recombinant expression plas-mids (Rv3478-pMV261 and Rv3478-pET-28a).The Rv3478-pMV261 plasmids were transformed into the BCG cells to construct the rBCG vaccine strains, while the Rv3478-pET-28a plasmids were transformed into Escherichia coli BL21 strains for the expression of Rv3478 protein.Polyclonal antibodies were induced in mice upon the immunization with Rv3478 protein.The rBCG vaccine strains overexpressing Rv3478 protein were screened out with Western blot assay.The C57BL/6 mice were divided into four groups including the PBS treated group, BCG treated group, rBCG::pMV261 ( R0) treated group and rBCG::Rv3478-pMV261 ( R3) treated group.All mice were sacrificed in 4 or 12 weeks after immunization.Enzyme-linked immunos-pot assay ( ELISPOT) , ELISA and flow cytometry analysis were performed to evaluate the induced humoral and cell-mediated immune responses in mice.Results The Rv3478 protein was successfully expressed and could induce polyclonal antibodies in mice.High levels of IFN-γand TNF-αwere detected in mice treated with R3, indicating that the immunization with R3 enhanced the cellular immunity.Moreover, the ratios of CD4+to CD8+T cells and the percentages of CD44+CD62L+T cells were increased in mice upon the immuni-zation with R3.Conclusion The recombinant BCG vaccine strain overexpressing Rv3478 protein could in-duce stronger cell-mediated immune responses in mice.It might be have a great significance as a new tuber-culosis( TB) vaccine strain against TB infection in the future.
ABSTRACT
Objective To evaluate the effect of high-frequency chest well oscillation expectoration system on ventilator-associated pneumonia (VAP) and time for withdrawing mechanical ventilation (MV) system in ICU patients with invasive mechanical ventilation (IMV). Methods 100 ICU patients with IMV were divided into observationgroup (n = 50) and control group (n = 50). The high-frequency chest well oscillation expectoration was used in the former group and the mechanical vibration expectoration was used in the latter. The two groups were compared in terms of amount of sputum, vital signs (heart rate, breathing, systolic blood pressure and blood oxygen saturation), time for withdrawing MV system and VAP rate. Results On days 1, 2, 3, 4 and 5, the amount of sputum in the observationgroup was (33.5 ± 4.2)mL/d, (41.1 ± 3.0)mL/d, (38.2± 3 .5) mL/d, (34.8 ± 2.5) mL/d and (31.1 ± 2.1) mL/d, and those of the control group respectively was (27.4 ± 3.1) mL/d, (30.3 ± 3.6) mL/d, (28.1 ± 2.2) mL/d, (25.7±1.8)mL/d and (20.8 ± 1.7)mL/d. The differences between the two groups were statistically significant (P 0.05). The time for withdrawing MV system in the observationgroup and the control group respectively was (5.8 ± 2.2)d and (9.5 ± 1.8)d, (P < 0.05). The rates of VAP in the observationgroup and the control group respectively was 30.0% (15/50) and 52.0% (26/50), with significant difference between them (P < 0.05). Conclusion The high-frequency chest well oscillation expectoration for ICU patients with invasive mechanical ventilation can promote sputum expectoration , improve blood oxygen saturation , shorten the time for withdrawing the ventilator, and prevent the incidence of VAP.