Study On Immune Effect Of C-type Lectin Receptor MR And Dectin-2 Of Dendritic Cells During Trichinella Spiralis Infection

As a kind of worldwide distributed zoonoses, Trichinosis is dangerous and harmful, which results in great economic losses to animal husbandry. The immune mechanism of parasites has not been clarified clearly yet because of their complicated structures and life cycles,which brings out trouble in prevention and remedy of parasitic diseases. Parasitic immune evasion has always been a hot spot for parasitology research. To figure out the functions of MR and Dectin-2 in Trichinella spiralis(T.spiralis)infection process, we analyzed and compared the expression changes of MR and Dectin-2 on the surface of dendritic cells of mice in vivo and in vitro, then detected the maturity of dendritic cells after sensitization of T.spiralis ES antigens to verificate the roles of this two receptors in T.spiralis infection, providing support for the following related research. Specific contents and results are as follows:(1)The influence of challenge of T.spiralis,the expression levels of MR and Dectin-2 which are on the surface of dendritic cells: 84 female BABL/c mice were random put into two groups, and experimental group received intragastric administration of 300 muscle larvae of T.spiralis. The mice were sacrificed on day 7, 14, 21, 28, 35 and 42 after challenge. The spleens and mesenteric lymph nodes(MLN)were dissected and single-cell suspensions were prepared. The expression of dectin-2 on dendritic cells(DCs)in the spleen and MLN was detected by flow cytometry. The flow cytometry results showed a significant decrease(P﹤0.05)of MR and Dectin-2 from spleen at day 7 after challenge. Then, there were no significant alteration of the two receptors in spleen; But MR in mesenteric lymph nodes decreased and Dectin-2 increased(P﹤0.05).MR on the surface of DC in MLN increased on day 14,21,35 after challenge. Dectin-2 increased on day21, 28 after challenge.(2)The influences of T.spiralis ES antigens to MR and Dectin-2 on dendritic cells: T.spiralis ES antigens were prepared and BMDC were cultured in vitro. MR and Dectin-2 both decreased on 6、12、24、36 hours after sensitization of the antigens and they both return to normal levels 48 hours after sensitization.(3)The infection of MR and Dectin-2 in T.spiralis challenge process to DC maturation: The cultured dendritic cells were divided into six groups: Negative control group(the DC),positive control group(DC + the ES antigens),the MR inhibited control group(DC + the MR inhibitors), inhibition of the control group bis(DC + dual inhibitors),inhibition of the MR experiment(DC + inhibitor of the MR + ES antigens)and dual inhibition group(DC + dual inhibitor antigen + ES antigens),and five deputy holes were set in each group. First,we added the appropriate inhibitor.Then, added ES antigens and replaced the DC ordinary medium after 15 minutes of actions. Finally after 48 h,we detected CD80 and CD86 by flow cytometry. The results of flow cytometry showed that after repressing MR receptors, CD80 and CD86 which locate on the DC pulsed T.spiralis ES antigens increased(P <0.05), which indicates T.spiralis can use MR to repress DC maturation. The maturation of DC pulsed T.spiralis ES antigens after repressing MR and Dectin-2 simultaneously was as same as that of the control group.The experiment proved that T.spiralis ES Antigens could inhibit the recognition of dendritic cells by MR. it will provide theoretical foundation for the study of immune evasion of T.spiralis.