Chemokine can regulate the immuue cells migration, play the function by combining chemokine receptor. Dendritic cells(DC) are the most important professional antigen presenting cells, and their main application is prepared into a variety of cancer vaccine. Dendritic cells need to migrate while completing the functions, are related with chemokine and chemokine receptor. Chemokines always playe a regulating, promoting or inhibiting role in the processing of completing the functions and migration. So DC can present antigens, activate the initial T cells, cause immune response and kill the tumor cells and inflammatory molecules.

Objective:To understand and determine the biological properties of Chlamydia pneumonia (Cpn) hypothetical protein Cpn0423 and the mechanisms of which involved in Cpn0423-induced inflammatory response. Methods:The biological properties of Cpn0423 gene were analyzed using bioinformatic software. The subcellular localization of nucleotide-binding oligomerization domain-like receptor 2 (NOD2) in bone marrow-derived macrophages (BMDMs) was detected by confocal microscope. NOD2-siRNA was used to inhibit the expression of NOD2 at mRNA level. Cpn0423-induced macrophage inflammatory protein 2 (MIP-2) and IL-6 production in BMDMs were detected by ELISA. PCR was performed to detect Cpn0423 DNA in bronchoalveolar lavage fluid (BALF) of Cpn-positive patients.Results:The homology between Cpn0423 and other type Ⅲ secretion system effector proteins of Chlamydia ranged from 85% to 93%. NOD2-siRNA could effectively inhibit the expression of NOD2 at mRNA level in BMDMs ( P<0.001). Moreover, Cpn0423-induced production of MIP-2 [(920.5±99.1) pg/ml vs (130.1±11.5) pg/ml, P<0.001] and IL-6 [(266.2±58.4) pg/ml vs (165.7±21.5) pg/ml, P<0.001] in BMDMs were decreased following NOD2-siRNA pre-treatment. Cpn0423 DNA was detected in the BAlF of 83.3% (10/12) of Cpn-positive cases, but not in Cpn-negative cases. Conclusions:Cpn0423 induced inflammatory response in host cells through NOD2 pathway, which was closely related to the chronic inflammatory injury caused by Cpn.