Application of the recombinant protein MOMPVD2-VD3 from Chlamydia pneumoniae in sero diagnosis

Abstract:

To express the recombinant protein MOMP_VD2-VD3 of Chlamydia pneumoniae，and research on the immunocompetence of the MOMPVD2-VD3 to support serodiagnosis，PCR and gene recombinant technique was used to clone the targeted DNA fragment from a strain AR-39. The recombinant plasmid was induced in E.coli BL21 after having constructed the prokaryotic expression system，then the immunocompetence of the expression product was analyzed by Western blot and indirected ELISA which is based on the animal experimentation. A group of control sera and 126 sera from patients with coronary heart disease were examined by using ELISAs based on the recombinant protein (MOMP_VD2-VD3)，and then the results were evaluated comparing with a commercial ELISAs kit. The results of the Western blot and indirected ELISA showed ompAVD2-VD3 gene inserted in pET30a could express a recombinant protein with the molecular weight of 24kDa in BL21 and specifically reacted with the antibodies against the MOMP. Specific humoral response was elicited after immune the BALB/c mouse with protein and the specific antibody titer was more than 1∶20480. Using a panel of control sera，the participation of the recombinant antigen，the sensitivity and the specificity of the indirected ELISAs were 100% respectively. Comparisons between two methods in detecting 126 sero samples，the concordance of two tests was 96.3%. The results reported here show that the recombinant protein with excellent immunocompetence could benefit the research on the serodiagnosis to Chlamydia pneumoniae.

Key words:Chlamydia pneumoniae; major outer membrane protein; immunocompetence; serodiagnosis; indirected ELISA