Immunogenicity Of Omp2and Other Proteins Of Haemophilus Parasuis

Infections caused by Haemophilus parasuis in pigs have become worldwide at present. Hps can infect pigs at age of from two-week to four-mouth old. Virulent strains can particularly participate as fibrinous polyserositis, polyarthritis and meningitis or acute pneumonia without polyserositis and acute septicaemia. The course of Hps infection is particularly serious in specific-pathogen-free(SPF)herds and herds with a good health status where outbreaks are accompanied by high morbidity and mortality.Haemophilus parasuis were isolated from swine with polyserositis and arthritis in Hunan province. The strains were identified based on morphologic, cultural and biochemical characteristics of HPS. PCR test was developed to further determine the strains with one pair of primers designed according to the sequence of the HPS’16S rRNA gene. Sequence analysis showed the16S rRNA of the strains is serotype5.According to GenBank in Haemophilus parasuis complete sequence, chose the Omp1、Omp2、33D15、4plp3、 Tolce and PlpD gene was amplified by PCR with six pair of specific primers.Using restriction enzyme digestion treatment all protein gene of PCR product and expression vector recovery pET-28a(+), the gene connected to the pET-28a(+).SDS-PAGE analysis showed that pET-Omp1、Omp2、33D15、4plp3、 Tolce and PlpD in E. coli Rosetta (DE3) to achieve high expression, Omp1、 Omp2、33D15、Tolce、 PlpD protein expressed in the form of inclusion bodies;4plp3protein expressed in the form of soluble. When change the temperature down to the25℃, Tolce and PlpD become the soluble expression.The recombinant purified protein of Omp1、Omp2、33D15、4plp3、Tolce、 PlpD using aluminum hydroxide adjuvant mixed, then inoculated mice and observation.15days after the first immunization30days to strengthen the immune, immune3times in total; control group were not immune to any protein, using saline and commercial vaccine. As a results, Omp1、33D15and4plp3protein can’t protected mice from the Hps infection; Tolce and PlpD protein protection was16.7% (1/6); Omp2protein protection was33.3%(2/6). With this result, we conclude that use Tolce、PlpD and Omp2as vaccines have a protective effect. And Omp2as a vaccine effection was significantly higher than the other two. Comparison and analysis made by other staff about Hps out membrane protein, confirmed Omp2protein do exist to the good immunogenicity can be used as the candidate vaccine.