Effects Of Mycoplasma Pneumoniae Influenced The Porcine Nasal Cavity Dendritice Cells

Mycoplasma pneumonia of swine(Mps)is a highly contagious,chronic,infectious respiratory disease caused by Mycoplasma hyopneumoniae(Mhp).The infected swine are characterized by paroxysmal cough and dyspnea.The morbidity of Mps is about 30%～50%and the infection rate is as high as 75%in China.The widespread epidemic of Mps has brought huge economic losses to the pig industry.Mhp mainly colonize in porcine respiratory epithelial cilia,cause functional disorder of cilia as well as epithelial cells inflammation.Nasal dendritic cells(DCs)are widely distributed under the airway epithelial cells.DCs is the most powerful antigen delivery cells,play an important role in pathogenic microorganisms recognition and induce adaptive immune process.In this experiment,we first detect the distribution of DCs in porcine nasal cavity.Then we separate porcine bone marrow-derived DCs,through the interaction of Mhp with DCs to study the immune effects between Mhp and porcine DCs.Our findings may assist in the development of specific strategies and therapeutic approaches against this pathogen.1 Study on the distribution of dendritic cells in porcine nasal cavityPig nose nasal cavity and tonsils are respiratory first contact with antigen sites and play an important role in animal body against pathogens invasion process.Dendritic cells(DCs)are the most powerful antigen presenting cells in vivo and can effectively activate the adaptive immune response.The nasal and tonsil DCs have been reported in human and mice,but the phenotype and distribution of porcine nasal and tonsil DCs are still unclear.Therefore,this experiment selects MHCII,CD11b and CD 16 three type DCs specific antibody,we labeled DCs in the tonsil,nasal eustachian tube in soft palate of 10 February age three yuan Duroc crossbred pigs,DCs were observed and analyzed by fluorescence microscopy and laser scanning confocal microscopy.The results showed that the porcine nasal cavity,tubal tonsil and soft palate tonsil mucosa lamina propria distribution of CD11b+CD16+DCs and CD11b+MHCII+DCs.Tubal tonsil and soft palate tonsil lymphoid follicles also distribution of CDllb+CD16+DCs and CD11b+MHCⅡ+DCs,and the number of DCs in tonsil propria were three times more than lymph follicles.In the healthy state,there were almost no distribution of DCs between the nasal cavity and the tonsil epithelial cells.CDllb+DCs distributed beneath the epithelial cells of eustachian tube,only a small amount of CD11b+DCs could extend to the epithelial cells,These results showed that there were a certain amount of CDllb+CD16+DCs and CD11b+MHCⅡ+DCs distributed in the pig nasal cavity and tonsil.2 Effects of Mycoplasma pneumoniae influenced the DCs and lymphocytes in porcine nasal cavity in vivo.Mycoplasma hyopneumoniae(Mhp)is the primary etiological agent responsible for swine enzootic pneumonia(EP),a disease that cause tremendous economic losses all over the swine industry.Ahp is an important pathogen causing mycoplasma pneumonia in pigs,spray nasal spread is the main route of transmission.The upper respiratory tract mucosal immune cells,DCs and lymphocytes,as an important mucosal defense,the changes of these immune cells are not clear in the process of transmission and infection of Mhp,Therefore,application of double labeled fluorescent antibody method were used to observe the changes of DCs in nasal cavity,lymphocytes and secreting type of IgA after infection with Mhp.The results found that 28 days after infection of Mycoplasma hyopneumoniae,compared with the normal control group,the number of CD11b+CD16+DCs and CDllb+MHCII+DCs in the nasal cavity were significantly decreased.The number of CD3+T cells in nasal cavity and the number of secreting IgA positive cells decreased significantly compared with that of the control group.The results showed that the number of immune cells in the nasal cavity caused by Mhp were decreased,and the immunity of the nasal mucosa decreased,which may caused the infection of other respiratory pathogens.3 Effects of Mycoplasma pneumoniae influenced the immune function of porcine DCs in vitroDCs is the only antigen presenting cells in the body that can activate naive T cells,is a bridge linking natural and acquired immunity.The maturation and presentation abilities of DCs directly affect the level of immune response.In order to explore the effect of Mhp on the immune function of DCs,in this experiment,the precursor cells were isolated from the bone marrow of piglets,GM-CSF and IL-4 were combined to induced their differentiation into DCs and the morphology and surface molecules were identified.Subsequently,Mhp-168 stimulated DCs for 24 hours in vitro,the expression of DCs’ surface molecules and the level of cytokine expression were detected by flow cytometry,quantitative PCR method.Mixed culture of DCs and lymphocytes,the proliferation of lymphocytes were detected.The results showed that the expression of CD1a was significantly inhibited in the Mhp-168 stimulated DCs’ group compared with the control group,surface molecular expression of CD80/86 was not affected,surface molecule SLA-II-DR expression up regulation.Compared with the control group,the Mhp-168 stimulated DCs’ group significantly increased the expression level of IL-10 and significantly inhibited the expression level of IFN-γ.Mhp-168 stimulated DCs had no effect on lymphocyte proliferation.These results showed that Mhp-168 inhibited the DCs activation and the ability of the downstream T cells and induce the TH2 type immune response.