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Swine Edema (Edema disease of swine, ED) is produced by certain serotypes Chi shiga-like toxin-producing E. coli (STEC) weaned pigs caused by an acute fatal infectious disease. Edema of the eyelids, stomach, etc., ataxia, convulsions and paralysis is characterized. The disease incidence of acute death fast, high mortality. The disease mainly through the digestive tract infection, effective oral vaccine for the prevention and treatment of the disease has important significance for the characteristics of its mucosal infection developed. This study used extrusion method prepare gene mutant strain of E. coli SLT-IIe (O 139 *) microcapsules, the average particle diameter of the microcapsule product is 2mm, wrapped rate of 76%, and detecting a micro capsule artificial gastric acid-resistant ability, in the artificial intestinal juice enteric oral security. The results show: the microcapsules can tolerate pH 1.6 artificial gastric 3H, at pH 6.8 artificial intestinal fluid disintegrating release smoothly. The microcapsules of piglets security after oral piglet appetite, drinking water, weight gain, normal mental status, no adverse reactions. Nine 35-day-old weaned pigs were randomly divided into 3 groups (n = 3). Broth and PBS the mutant strain O139 * microcapsules mutant strain O139 * oral immunization, day 1, for 3d. Piglet serum specific IgG antibody and feces specific sIgA antibody levels detected by indirect ELISA method. The results show, the oral microencapsulated group piglets after immunization section 21 d 28 d detection to the anti-O antigen of IgG antibodies (P / N gt; 2); immune after the first 14 days, for 21 d, 28 d detection to the anti- F18ab pili protein of IgG antibodies (P / N gt; 2); immune after the first 7 d detection to the anti-SLT-Ⅱ eA protein of IgG antibodies (P / N gt; 2); against SLT-Ⅱ eB protein IgG and before immunization did not change significantly. Oral micro-capsule group piglets in immune first 7 d, for 21 d, 28 d, detection to the anti-SLT-Ⅱ eA protein sIgA antibodies (P / N gt; 2); immune Section 14 d, 21 d detection to the anti-O antigen sIgA antibody (P / N gt; 2); 7 d after immunization detected the sIgA antibody anti-SLT-Ⅱ eB protein (P / N gt; 2). Oral bacterium group piglets after immunization also detected for the above antigen-specific IgG and sIgA antibody levels lower than the oral microcapsule group. Not detected in the serum and feces from piglets in the control group to specific IgG and sIgA. Using an ELISA kit to detect the immune piglets serum before and after IL-4, IL-10, IFN-gamma content changes. The results showed oral microencapsulated piglets serum IL-10 significantly increased pre-immune 219.95 pg / mL, two weeks after immunization, reached 354.65 pg / mL; elevated IL-4 content, pre-immune 58.146 pg / mL, immune three weeks to reach 75.762 pg / mL; IFN-γ did not change significantly. After the third immunization 21d, can still be detected in fecal samples from the the oral microcapsule group and oral bacterium piglets mutant strains. In after the last immunization 28d, respectively, from the the oral the microcapsules group and control group randomly selected one piglet after ear vein injection 0.8mlSLT,-Ⅱ e microcapsules piglets only a short period of time do not want to walk around, loss of appetite, 24h return to normal. The control group of piglets appetite waste must, fever, downer. Experimental pigs were sacrificed 72 h after the tissues and organs of the microcapsules piglets visible pathological changes, the control group piglets liver edge necrosis, the lungs were cellulose-like lesions, gastric and gallbladder edema; histological pathological changes of gastric submucosa edema, liver degeneration, necrosis, lung, kidney, spleen, vascular wall permeability, exudation of RBC. The research results show that the microcapsules has good resistance to gastric protective effect of mutant to release in the intestine resulting from the colonization, further induce humoral immunity, mucosal immunity of piglets to have a good immune protective effect on the immune piglets. The mutant strain as Swine Edema mouth taking poison to force gene deletion vaccine candidate strains.
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