Preliminary Study On PCV2 Induce Disorder Of The Intestinal Mucosal Immune Function

Porcine circovirus type 2 (PCV2) is the primary causative agent of several syndromes collectively known as porcine circovirus-associated disease (PCVAD). PCVAD can be subclinical or include 1 or more clinical manifestations including Post-weaning multisystemic wasting syndrome (PWMS) with weight loss and high mortality, respiratory disease, porcine dermatologic and nephropathy syndrome (PDNS), Reproductive failure/sow abortion and mortality syndrome (SAMS), congenital tremor type (CT) PCV2-Assciated Pneumonia PCV2-Assciated Enteritis and so on.119 Distinguishing the different forms of PCVAD can be accomplished by observation histopathologic characteristic lesions in the intestines, lungs, and lymphoid tissue[37].These disease make a very serious economic loss in Chinese pig farms. The PCV2 induced enteritis is a problem that cannot be neglected in the special pig model of China,the clinical symptoms is diarrhea, emaciation and loss of appetite. Intestine is the immune organs that had the bigest superficial area.In order to study the mechanism that PCV2 induced the piglets’ diarrhea.Several aspects about PCV2 induce the intestinal function damage are studied in this paper. 1.PCV2 induced intestinal immunosuppression in hostPCV2 causes lesions in mice that are similar to lesions that PCV2 infected piglets, so the BABL/c mice was used to model,the Peyer’s patches lymphocyte was extracted on days 7,14,21,28 and 35 PI by a reasonable method, then dectect the lymphocytic apoptosis by flow cytometry. The MLN lymphocytes of newborn piglets’s that pregent sows was inoculated at 75 days of gestation were extracted and dectected by the experience from mice.the experiment result show that flow cytometry can detect the lymphocytic apoptosis when the lymphocytes were extracted by a reasonable method. The apoptotic cell is increase with the increase of infection time. The research laid a foundation that PCV2 induced the piglets’lymphocytes apoptosis. The apoptotic cells are higher in MLN infective piglets, compared with control piglets.the result confirm the PCV2 could cause the disorder of intestine normal immune function by the MLN lymphocytic apoptosis. 2.The impact of PCV2 on piglets intestinal SIgA and cytokine contentBecause the intestinal lymphocytes apoptosis was a part of reason that disorder of intestinal immune function, the study detect the SIgA that is intestinal-associated protein and content of IL-2,IL-4,IL-10,IFN-γ and TGF-β which called intestina related cytokines,the experiment result show,both the level of SIgA, IL-2,IL-4,IL-10,IFN-γ and TGF-β were changed inordinately,the disorder of intestinal immune level lead to the disorder of intestinal immune function.Taken together,this paper confirm the PCV2 had a very serious disorder of intestinal immune function by detecting the level of SIgA, IL-2,IL-4,IL-10,IFN-γ and TGF-β. This discover provided a part of theoretical basis of piglets’ diarrhea.