Inhibitory effects of the Chlamydiaphage phiCPG1 capsid protein Vp1 on Chlamydia psittaci strain guinea pig inclusion conjunctivitis and Chlamydia trachomatis serovar E / 中华皮肤科杂志

ABSTRACT

Objective To evaluate inhibitory effects of the Chlamydiaphage phiCPG1 capsid protein Vp1 on Chlamydia psittaci strain guinea pig inclusion conjunctivitis (GPIC) and Chlamydia trachomatis (Ct) serovar E,and to provide new ideas for the treatment of Ct infection.Methods The Chlamydiaphage phiCPG1 capsid protein Vp1 was expressed in Escherichia coli BL21 transfected with the recombinant plasmid Vp1-pET30a (+),identified by Western blot analysis and purified by using dialysis bags.Bicinchonininc acid (BCA) assay was performed to determine the concentration of Vp1 protein.GPIC and Ct serovar E strains were both classified into 4 groups to be firstly incubated with Vp1 protein (Vp1 group),Tris-glycine solution (Tris group),S protein (S group) or Dulbecco's Modified Eagle Medium (DMEM,DMEM group) at room temperature for 3 hours,then were used to infect Hela cells followed by 72-hour (GPIC) or 48-hour (Ct serovar E) culture with the presence of Vp 1 protein (Vp 1 group),Tris-glycine solution (Tris group),S protein (S group) or DMEM (DMEM group).Subsequently,immunofluorescence staining was conducted to observe and count chlamydial inclusions.Results The number of GPIC inclusions was significantly different between the 4 groups after 72-hour culture (F=476.632,P＜ 0.05),and lower in the Vp1 group (5.0 ± 1.5) than in the Tris group (24 ± 1.2,P＜ 0.05),S group (25 ± 1.7,P＜ 0.05) and DMEM group (25 ± 1.5,P＜ 0.05),but insignificantly different between the latter 3 groups (P ＞ 0.05).Compared with the DMEM group,the Vp1 group showed a significant decrease of 80.2％ ± 3.99％ and 77.2％ ± 1.79％ in the number of GPIC and Ct serovar E inclusions respectively,with no significant difference in the inhibitory effect of Vp1 on GPIC versus Ct serovar E (t =2.057,P ＞ 0.05).Conclusion The phiCPG1 capsid protein Vp1 can obviously inhibit GPIC and Ct serovar E infections to a similar degree.