[Cloning and expression of Chlamydia trachomatis OmcBc gene and antigenicity analysis of the protein].
OBJECTIVE
To investigate the antigenicity of recombinant Chlamydia trachomatis (Ct) OmcBc protein and search for the new target for early diagnosis of Chlamydia infection and Chlamydia vaccine development.


METHODS
The C fragment of OmcB encoding the amino acids from T270 to T553 was amplified from Chlamydia serovar D genomic DNA. The pGEX-6p-Ct OmcBc expression plasmid was constructed and transformed into E.coli XL-1blue. The expression of recombinant Ct OmcBc protein was induced by IPTG. Serum samples were collected from 120 patients with urogenital Chlamydia infection. The antiserum samples were collected from 7 New Zealand white rabbits and 5 Balb/C mice immunized subcutaneously and intraperitoneally with Ct serovar D inactivated EB, respectively, and from 9 Balb/C mice intranasally infected with Ct serovar D live EB. The anti-Chlamydia specific antibody were titrated by an immunofluorescence assay (IFA). The reactivity of the recombinant OmcBc protein with all the above antisera was detected by ELISA.


RESULTS
The pGEX-6p-Ct OmcBc expression plasmid was successfully constructed. DNA sequencing showed that the inserted OmcBc was about 852 bp, encoding a protein with 284 amino acids. The expression of the recombinant GST-OmcBc was induced by IPTG, producing a fusion protein with a molecular weight of about 57 kD. The titer of the specific antibodies to Chlamydia in all the antisera was high. ELISA results showed strong reactivities of the recombinant GST-OmcBc fusion protein with all the above antisera.


CONCLUSIONS
OmcBc protein is an immunodominant protein of Chlamydia. The recombinant GST-OmcBc with strong antigenicity may provide a basis for further study of early diagnosis of chlamydia infection and development of Chlamydia vaccine.
Wang
Jie
J
Department of Immunology, Basic Medical School of Central South University, Changsha 410078, China. jiewang0988@yahoo.com.cn
Zhang
Ying-qian
YQ
Zhong
Guang-ming
GM
Yu
Ping
P
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000276:immunology* / Q000378:metabolism; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics* / Q000276:immunology; D002692:Chlamydia trachomatis / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D003001:Cloning, Molecular; D005798:Genes, Bacterial; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D010957:Plasmids; D011817:Rabbits
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D007106:Immune Sera; C436968:OmcB protein, bacteria