The Effect Of Chlamydiaphage Capsid Protein Vp1 On The Chlamydia Psittaci Strain Guinea Pig Inclusion Conjunctivitis And Chlamydia Trachomatis

Chlamydia trachomatis(C.t) infection is the most prevalent sexually transmitted disease in the world. With the development of bacteria drug resistance, the treatment of C.t infection becomes more and more difficult, moreover, due to the special biological characteristics of Ct, treatment failures become common. Researches of C.t related vaccines still reach no satisfactory achievements until now. National and international researches turn to Chlamydiaphage and related studies suggest that as the second found Chlamydiaphage, phi CPG1 capsid protein Vp1 can inhibit the growth of D and E Chlamydia trachomatis, the Chlamydia trachomatis will stay in the period of reticulate body and mature infectious initial body will not be developed,abnormal large reticulate body will appear. Therefore, Vp1 may have underlying clinical value.Vp1 is the main capsid protein of phi CPG1, and it can bind to receptor proteins on the Ct, which plays important role in the adhesion and implantation of phage to Ct. Vp1 protein includes a large inner ring(IN5 ring), the ring is mushroom shaped, and researches suggest that IN5 ring may be the underlying domain where the phage combine with Ct. Our previous researches have found that Vp1 protein can inhibit the growth of D,E and Ct clinical strains. This study aims to further explore the effect of Vp1 protein on Chlamydia psittaci strain guinea pig inclusion conjunctivitis(GPIC) and Ct strains D,E,F,G,H,I,K,L2.Objective Recombinant capsid protein Vp1 of phi CPG1 is expressed largely in vivo, and it was used to act on GPIC and Chlamydia trachomatis strain D, E, F, G, H, I, K,L2 to observe its inhibition effect on all these types. To provide a new therapy to treat clinical Chlamydia infection.Method Optimized recombinant plasmid was used to express Vp1 protein in Escherichia Coli.After collection, identification and purity, Vp1 was incubated with GPIC and different Ct strains for 3 hours, then Chlamydia was inoculated into Hela cells, different concentrations of Vp1 were added during Chlamydia culture, the optimum concentration of Vp1 was determined according to the change of cell growth line and MTT method. Inclusion body was calculated by immunofluorescence and iodine staining. The effect of Vp1 on other pathogens, such as mycoplasma, gonococcus,staphylococcus aureus, streptococcus and klebsiella pneumonia, was also detected by liquid culture medium dilution method.Results Vp1 can obviously inhibit the growth of GPIC and Ct, the action concentration was51.2ug/ml, the inhibition rate of GPIC was 80.2%, the inhibition rate of different Ct strains was 69.8-86.7%. However, effect of Vp1 on other pathogens was not significant.Conclusion The phi CPG1 capsid protein Vp1 can inhibit the growth of GPIC and other different Ct strains significantly, and have no significant effect on other pathogens.