The Primary Research Of Outer Membrane Proteins Complex From Serogroup B Neisseria Meningitidis

N.meningitidis group B is the most important cause of epidemic meningitis,which comprizes many serotypes on the basis of the immunologic reactivity of their PorA outer membrane proteins.However,relative to the other serogroups,they are devoid of cross immune response among the serotypes.Vaccine research against serogroup B meningococcus has mostly focused on outer-membrane proteins(OMPs) and outer-membrane vesicles(OMV).Native OMV consist of intact outer membrane and contain outer-membrane proteins(OMPs) and lipooligosaccharides(LOS).They readily can be prepared by detergent extraction from the bacteria.The major outer-membrane proteins(OMPs) from Neisseria meningitidis are subdivided in five classes based on molecular weight.Classâ… OMPs are cation selective porins and induce formation of bactericidal antibodies;Classâ…¡and Classâ…¢are anion-selective porins and are self-exclusive,so never expressed simultaneously, antibodies against classâ…¡/â…¢are only occasionally protective and bactericidal;The function of classâ…£OMPs is unknown but they may have pore-forming properties. Antibodies against classâ…£OMPs can block the bactericidal activity of classâ… and classâ…¡/â…¢OMPs-specific antibodies,rendering the bacteria less immunogenic,for this reason,classâ…£OMPs are not interesting to isolate for vaccine purposes,it is important to eliminate these proteins from other OMPs islates;Classâ…¤OMPs play a role in bacterial adhension to and invasion of host cells,and also are promising vaccine candidates.In this experiment,three representative strains have been selected.Outer membrane proteins(OMPs) of the above three strains were extracted from detergent, Their SDS-PAGE profiles were found to be different,but each of them possessed the bands of classâ… ,â…¡/â…¢,â…£andâ…¤OMPs.NIH mice were immunized by the subcutaneous injection of different dosage and injections of OMPs of 29356 strain. OMPs-specific immunoglobulin G(IgG) antibody titers in serum were determined by an enzyme-linked immunosorbent assay(ELISA).The results showed that:different doses of immunization could induce IgG antibody and titers could be up to 1:128000,so this OMPs have a good immunogenicity.Then I selected the best conditions to immune mice,then attacked by strains 29356,51169,29004,and observed protective effect of active and cross immunization.The results showed that:mice attacked by 10 LD50, group of 29356 strain survival rate was 100%,group of 51169 strain survival rate was 0%,group of 29004 strain survival rate was 0%,while the control group survival rate was negative,It showed that OMPs on the adult mouse have a certain extent of the protection when attackd by the same serotype of meningococcus,but may be devoid of cross immune protection against the other serotypes of meningococcus.