Biological effects of chlamydiaphage phiCPG1 capsid protein Vp1 on chlamydia trachomatis in vitro and in vivo

Abstract

The researches on chlamydia in recent years show that chlamydia bacteriophage may be a potential and effective means to solve the clinical infection of chlamydia trachomatis (Ct). We investigated the biological effect of chlamydiaphage phiCPG1 capsid protein Vp1 on Ct both in McCoy cells and genital tract of mice. Different concentrations of Vp1 were co-incubated with Ct E serotype strain in McCoy cells. Female BALB/c mice were used to establish Ct E strain-induced urogenital infection model. They were randomly divided into five groups and given different treatments on the fifth day after Ct inoculation. Animals in groups 1 and 2 were given 30 μL different concentrations of Vp1 in the genital tract respectively, those in group 3 were intramuscularly injected with 30 μL Vp1, those in the infected group did not receive any intervention, and those in the control group received 30 μL PBS in the genital tract. The vaginal discharge was collected to identify the live chlamydia by cell culture and gene fragment by real time PCR different days after infection. Inhibition rate of 100 μg/mL and 50 μg/mL Vp1 proteins against Ct E strain in the McCoy cell cultures was 91% and 79% respectively. The number of intracellular Ct inclusion in the McCoy cells co-cultured with vaginal discharge of group 1 and group 2 was less than in the infected group, and that in group 1 was less than in group 2, on the 7th day after Ct inoculation. Real-time PCR showed that chlamydia concentration of the vaginal discharge in group 2 was lower than in the infected group, and that in group 1 was lower than in group 2 on the 10th day. It was suggested that Vp1 capsid proteins had inhibitory effect on the proliferation of Ct serovar E strain in cell culture and mouse genital tract.

Applications of bacteriophages against intracellular bacteria

“…The Vp1 capsid protein of uCPG1 has been shown to be able to significantly impair the growth and proliferation of C. trachomatis within target cells (Ma et al 2017). This was also observed in in vivo experiments in a murine model of genital infection with this bacterium (Wang et al 2017). The genes marking the presence of Vp1 and also antibodies against this protein were detected in a few patients infected with C. trachomatis, which suggests that uCPG1 may be concomitant with infections caused by this bacterium (Ma et al 2016).…”

Potential for Phages in the Treatment of Bacterial Sexually Transmitted Infections

“…They are group II bacteriophages from the family Microviridae and the subfamily Gokushovirinae [40]. Reports indicate that ΦCPG1 capsid protein VP1, as well as ΦCPG1 phage itself, has disruptive effects on the growth of C. trachomatis in vitro [41][42][43][44][45]. In vivo ϕCPG1 delays appearance of Chlamydia caviae and decreases pathological response in a Guinea pig animal model [46].…”

“…Evidence indicates that enzymes from the isolated Streptococcus and Chlamydia phages can target S. agalactiae and C. trachomatis to impact their growth. Phage enzymes targeting C. trachomatis have displayed success in vitro [ 42 , 43 , 44 , 45 ]. In addition to genetically engineered recombinants [ 125 ], phage enzymes targeting S. agalactiae have been successful in vitro [ 60 , 63 , 64 , 65 , 72 ] and in vivo [ 68 , 73 , 74 ].…”

“…In addition to genetically engineered recombinants [ 125 ], phage enzymes targeting S. agalactiae have been successful in vitro [ 60 , 63 , 64 , 65 , 72 ] and in vivo [ 68 , 73 , 74 ]. For C. trachomatis , reports indicate that φCPG1 phage capsid protein Vp1 has disruptive effects on its growth in vitro [ 42 , 43 , 44 , 45 ]. φCPG1 itself has shown a delayed appearance of Chlamydia caviae in a Guinea pig animal model and a decreased pathological response [ 46 ].…”

Capsid protein Vp1 from chlamydiaphage φCPG1 effectively alleviates cytotoxicity induced by Chlamydia�trachomatis

“…Vp1 capsid proteins of φCPG1 have been demonstrated to inhibit C. trachomatis growth and cause a decrease in the number of C. trachomatis inclusion bodies during infection ( 15 – 17 ). Vp1 has also been indicated to exert inhibitory effects on the proliferation of C. trachomatis in the mouse genital tract ( 16 ). In the present study, whether Vp1 alleviates the cytotoxicity induced by Chlamydia trachomatis was investigated.…”