Preparation Of Trivalent Inactivated Vaccine Of Streptococcus Suis And Evaluation Of Immune Effect On Mice

Swine Streptococcosis is a zoonotic disease caused by Streptococcus suis,Streptococcus maris subspecies,Streptococcus maris subspecies and D、E、L groups of Streptococcus in the Lancefield subgroup.It is clinically characterized by lymph node abscess,meningitis,arthritis,endocarditis and septicemia.Streptococcus suis(Streptococcus suis,SS)is the most important pathogen of Streptococcus suis in the world.According to the antigen characteristics of capsular polysaccharide on cell surface,it can be divided into 35 serotypes,that is,1-34(SS1-34)and 1/2(SS1/2),Among them SS2 the most common,the most popular,the most pathogenic,Seriously affected the development of pig industry.In the current comprehensive development of anti-resistance,anti-resistance breeding trend,vaccination has become the main measures to prevent the disease.Inactivated seedlings are widely used in production because of their safety,short development period,easy preservation and preparation of multivalent seedlings.The use of multivalent vaccine can completely protect the animals caused by pathogenic microorganism.Three strains of SS vaccine strain(HF2、BB15-4、HBgu18-4 strain)were selected to prepare the inactivated trivalent(serotype 2,3,4)vaccine by mice pathogenicity,antigenicity and stability test in the previous period The aim of this paper is to provide technical reserve for the development of a new SS trivalent inactivated vaccine and to lay a foundation for the effective prevention and control of Streptococcus suis.The following experiments were carried out in this study using three SS vaccine strains selected :(1)the SS trivalent inactivated vaccine with formaldehyde as inactivated agent and ISA 201 VG mineral oil as adjuvant was prepared for three live bacteria concentrations(1.0×109 CFU/m L,2.0×109 CFU/m L and 4.0×109 CFU/m L).the vaccine was qualified or not by physical character test,aseptic test and safety test.(2)immunize mice with V-a、V-b、V-c and commercial vaccines,respectively(named immune groupsⅠ、Ⅱ、Ⅲand Ⅳ in turn),Using indirect ELISA method to detect antibody titers and related cytokines in serum Ig G immune groups(IL-4、IL-10、IFN-γ、TNF-β、MCP-1);Detection of functional antibody level by serum sterilization test;Thiazole blue brominated tetrazole solution(MTT)to determine the spleen lymphocyte proliferation index(SI);The percentage of lymphocyte subsets T CD4 and CD8 peripheral blood by flow cytometry;To determine the immune protection rate,The number of tissue-charged bacteria was determined to determine the colonization of the virus-tapping strain in vivo,and the pathological tissue sections of lung,liver,spleen and kidney were collected to observe the pathological changes.The results showed that :(1)the SS trivalent inactivated vaccine was oil-in-water(W/O/W),And meet the inspection requirements of oil emulsion inactivated vaccine.(2)7 d,after exemption The serum Ig G antibody titers of I ~ IV mice were 1:12800;There was no significant difference between I ~ IV in immune group(P>0.05),After 2 immunity 7 d all have strong germicidal effect;The levels of relevant cytokines,proliferation index of splenic lymphocytes ~ percentage of peripheral blood T subsets in immune group I and IV mice were increased continuously without significant CD4 and The immune protection rate of I ~ IV in immune group was 86.67%,100%,100% and 80%;the bacterial colonization of organs(lung,liver,kidney and spleen)of I ~ III mice in immune group was the lowest and significantly lower than that in immune group IV(P<0.05)in immune group 7.The results showed that :(1)the SS trivalent(serum type 2,type 3,type 4)inactivated vaccine of three living bacteria concentrations(1.0×109CFU/m L、2.0×109CFU/m L、4.0×109CFU/m L)was successfully prepared by using HF2、BB15-4、HBgu18-4 strain as vaccine-making strain,formaldehyde as inactivated agent and mineral oil as adjuvant,named V-a、V-b and V-c.respectively To evaluate the immune efficacy of V-a、V-b and V-c using Kunming mice as experimental animal model The immune effect of V-b and V-c is the best,which can effectively resist the attack of SS2,SS3,SS4 virulent strain,and can be used as candidate vaccine for SS trivalent(serotype 2,type 3,type 4)inactivated vaccine.