ACTA VETERINARIA ET ZOOTECHNICA SINICA ›› 2017, Vol. 48 ›› Issue (2): 307-315.doi: 10.11843/j.issn.0366-6964.2017.02.014

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Evaluation of the Immune Effect of Microencapsulated E. coli Inactivated Oral Vaccine in Rats

XIA Rui-yang1，XU Xin-long1，2，DONG Ming-di1，CHEN Li-jing1，QI Lai-fang1，WANG Ling3，YAO Gang1*   

  1. (1．College of Veterinary Medicine，Xinjiang Agricultural University，Urumqi 830052，China；2．Alashankou Entry-exit Inspection and Quarantine Bureau of the P．R．China，Alashankou 833418，China；3．Xinjiang Hope- Link Institute of Detection Technology，Urumqi 830019，China)
  • Received:2016-06-12 Online:2017-02-23 Published:2017-02-23

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Abstract:

The pathogenic E. coli of different serotypes is a major sort of the causative agents of the diarrhea of young animals. In the present study a microencapsulated E. coli inactivated oral vaccine was prepared and its immune effect in rats was evaluated. The prepared ovine pathogenic E. coli inactivated vaccine with propolis-adjuvant as the core material was microencapsulated by natural alginate polymer as wall material, in which 7.52×1011 bacteria•g－1 dry powder were encapsulated. A hundred Wistar rats were divided into randomly 3 groups, i.e., the control, injection immunization and oral immunization groups, in which the oral immunization group was futher-divided in to the basal dose, 10-fold dose and 20-fold dose groups. After the inoculation the specific antibody was tested by the micro-agglutination test and the indirect ELISA, and the cellular immunity and mucosal IgA were detected. The micro-agglutination test showed that the specific antibody was produced from day 7 after the inoculation and reached to the peak at day 28, then declined thereafter. The indirect ELISA test showed that the antibody was positive from day 14 to day 28 after inoculation. The antibody titers in oral vaccine groups were significantly higher than that in the control (P<0.05), but not in the injection group (P>0.05), and were not significantly between the oral vaccine groups (P>0.05). The antibody titers in the oral vaccine groups declined to negative level at day 35 after inoculation whereas the injection group remained to be antibody-positive；T lymphocyte transformation test showed that SI index in 3 oral vaccine groups was higher than that in the control or the injection group significantly (P<0.05). The sIgA levels in oral vaccine groups were also significantly higher that either in the control or injection group, reaching to the peak at day 21 after inoculation. These data suggest that microencapsulated E. coli inactivated oral vaccine could produce the humoral immunity equivalent to the injected vaccine but with better cell and mucosal immunity in rats.

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