| Recently, Anguilla Anguilla is one of the most popular breed of eel cultivated in China. After being imported, the scale and density of farming operations have been expanded rapidly. At same time, health securities of the eel are sometimes threatened by diseases, which dramatically decreases the benefits of farmers. Aeromonas hydrophilia is a common pathogen prevailed in eel farms. In order to explain the pathogenesis of Aeromonas Hydrophila, determine the immune reactions and provide scientific basis for future vaccination in practice of eels, the immune tissues morphology was observed, antibody secreting cells (ASC) were determined with ELISPOT, and nonspecific immune factors were measured after Anguilla anguilla vaccinated orally or injection with Aeromonas Hydrophila-ISCOMs. The results are listed below:1. Isolation of MOMP of Aeromonas Hydrophila and ISCOMs preparation: MOMP of Aeromonas Hydrophila was first isolated through optimized extraction conditions and ISCOMs was prepared with the method currently used in our laboratory. The MOMP and ISCOMs were tested by using SDS-PAGE and an electron microscope, persisting in their feasibilities and validating for making Aeromonas hydrophila-MOMP ISCOMs.2. Observation of the immune tissue morphological changes of Anguilla Anguilla after vaccination with ISCOMs, compared with control group:①The white pulp in the spleen is increased remarkably, but no other obvious pathological changes could be observed.②Villi are normal and the guts are remained structu -rally sound.③The number of lymphocytes in intestinal epithelium are different between oral vaccination and injection vaccination. In oral vaccinated group, the number of lymphocytes in the intestinal epithelium of the foregut and mid-gut are declined initially, and ascended to peak at the 21th day after vaccination (P<0.01). The number of lymphocytes in the hindgut are ascended slightly at the 7th day after vaccination, and then declined steadily. In injection vaccinated group, the number of lymphocytes in the intestinal epithelium of the foregut, mid-gut and hindgut are slight increased initially, and declined at the 7th day after the first vaccination, and then they are increased again to peak at 14th day, and then they are declined (P<0.01), except the number of lymphocytes of the hindgut are still maintained at high level to the 21th day (P<0.01), after the second vaccination.④The number of goblet cells in the intestinal epithelium of the foregut, mid-gut, and hindgut are all increased significan -tly in both oral vaccination and injection vaccination.3. Observations of the ASC of Anguilla Anguilla after vaccinations:①the number of ASC and specific ASC are higher in groups of both oral vaccination and injection vaccination than in control at the 14th day, and the 28th day. In kidney, the differences of the number of ASC and specific ASC are significant greatly at the14th day (P<0.01) and at 28th day (P﹤0.05) respectively after oral vaccination. In the group of injection vaccination, compared to control group, the number of ASC in kidney are kept in the normal level (P>0.05), and the specific ASC are increased significantly (P﹤0.05) at the 14th day. And then the number of ASC and specific ASC in kidney are increased significantly (P﹤0.01) at 28th day.②Compared with control group, the number of the cells in skin are increased continuously after oral vaccination, and the number of the cells in skin are increased in early stage, then declined to normal level at the 28th day after injection vaccination. The number of ASC in skin are increased significantly at the 14th day and the 28th day (P<0.01) after oral vaccination. The number of specific ASC in skin are increasted significantly at 14th day (P﹤0.05), and declined to normal level at the 28 day (P>0.05). The number of ASC and specific ASC in skin are increased significantly at the14th day (P<0.01)and at the 28th day(P﹤0.05) after injection vaccination.4. Non-specific immune factors in blood of Anguilla Anguilla after vaccination: the content of lysozyme, transferrin (Tf), and alkaline phosphatase (ALP) in the serum are higher in groups of oral and injected vaccination than the control. The interferon (IFN) titer in serum was higher in the injected group than in the control. Specific antibody secretion can be induced by either oral vaccination or injected vaccination. In conclusion, Aeromonas hydrophila-ISCOMs shows less irritation and no side effects are observed. The number of lymphocytes and goblet cells in the intestinal epithelium are both increased in different degree by oral vaccination or injected vaccination, indicating that local immune responses are induced by vaccination of aeromonas hydrophila-ISCOMs. The number of ASC and specific ASC of kidney and skin in vaccinated groups are obviously higher than that in the control, and activities of non-specific immune factors (lysozyme, transferring, alkaline phospha -tase, interferon) in blood of vaccinated groups are evidently enhanced, compared with control group, showing that immunoreactions are improved after vaccination with Aeromonas Hydrophila -ISCOMs. |
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