Serologic Screening And Optimizion Of Chlamydial Immunodominant Proteins In Chlamydia Trachomatis Infection

In recent years, Chlamydia trachomatis(C.t) urogenital infection becomes the most common sexually transmitted disease,and it is also the first of sexually transmitted diseases in our country. C.t infection has caused more and more serious complications, and significantly increases the risk of HIV infection, associating with the formation of cervical cancer. Another important feature of C.t infection is that the symptoms of occult, C.t infectors often become an important source of infection and reservoir owners. Early detection of C.t infectors disease control is very important to control disease.Currently on our broad clinical the main target proteins used for C.t detection kits are Chlamydial LPS(Lipopolysaccharides),Chlamydial MOMP(major outer membrane protein, MOMP) or heat shock protein 60(Chlamydial heat shock protein60, HSP60). LPS lack of specificity, with other pathogens Lps antigen has certain cross-reactions. Although HSP60 and MOMP have good specificity, but sensitivity is not enough, it may lead to misdiagnosis.Recent studies show that antigenicity of these two proteins are not strong enough. To screen C.t infection better antigenic protein,In our study, we express 8 C.t immunodominant proteins while MOMP HSP60 as a control. Then we collect clinical C.t infected and uninfected person’s sera. ELISA is adopted to detect antibodies to these four C.t proteins in the sera.Objective: To express 8 Chlamydia trachomatis immunodominant proteins,Chlamydial plasmid-encoded protein 3 Pgp3 Chlamydial Protease-Like Activity Factor CPAF,C.t143 encoded protein CT143,C.t101 encoded proteinCT101,C.t694 encoded protein CT694, C.t875 encoded proteinCT875,C.t813 encoded protein(CT813) and C.t119 encoded protein(Inc A),while C.t MOMP and C.t HSP60 as a control and verify the antigenic of these four proteins.To explore C.t antigen proteins suitable for early screening of C.t infection.And to optimize C.t immunodominant proteins suitable for serological screening of C.t infection.Methods: The recombinant plasmids encoding the 10 proteins and blank plasmidwere transformed into E. coli respectively. The proteins’ expression were induced by IPTG.The lysates wereused to coat glutathione precoated 96-well ELISA plates. 50 sera of C.t infected persons and 30 sera of C.t uninfected persons in our STD clinic were collected. ELISA was adopted to detect the antibodies of the ten recombinant proteins. The result was compared with that of immunofluorescence(MIF)and urogenital swab C.t Culture. to Determined have the highest sensitivity and specificity of antigen protein composition.Results: 1.The study completed extraction identification and sequencing to the10 recombinant plasmids and p GEX-6p-2 empty plasmid.2.The study completed the expression purification and identification to the10 kinds of fusion protein and empty plasmid GST protein.3. In the 50 C.t infected persons’ sera 10 the antibodies detected results are Pgp3 88% 44/50, CPAF 76% 38/50, CT143 74% 37/50, CT101 72%36/50, CT694 66% 33/50, CT875 62% 31/50, CT813 60%(30/50, MOMP52% 26/50, Inc A 48% 24/50 and Hsp60 34% 17/50. In the 30 sera of C.t unfected persons only detected CT143 26.7%(8/30) CT101 16.7% 5/30, The rest were not detected.4. In the 50 sera of C.t infected persons 44 samples were positive for MIF and 14 were positive for C.t culture. In the 30 sera of C.t unfected persons MIF and C.t culture are all negative. 3. Its positive coincidence rate with MIF and C.t Culture were97.73%(43/44) and 92.86%(13/14). In the 30 cases with negative results of MIF detection, no antibody anti Pgp3, CT694 or CT875 was found.5. C.t immunodominant protein composition of Pgp3, CT694 and CT875 serologic test results Compared with microimmunofluorescence and Chlamydia trachomatis cell culture positive coincidence rate respectively 97.73%(43/44) and92.86%(13/14). 30 cases of detected MIF antibody-negative serum samples the three proteins composition were not detected.Conclusions: 1.In the 10 studied proteins Pgp3 showed the highest antigenicity,the following were CPAF and CT143,HSP60 showed the lowest antigenicity.2. Combination of Pgp3, CT694 and CT875 antibodies detection was suitable forserological screening of C.t infection. Its good sensitivity and specificity and simple operation makes C.t screening possible.