Evaluation on immune effect of group C meningococcal polysaccharide conjugates using protein D of Haemophilus influenzae type b as protein carrier
10.13200/j.cnki.cjb.004305
- VernacularTitle:b型流感嗜血杆菌奈瑟球菌荚D蛋白作为载体的膜多糖C群脑膜炎-蛋白结合物的免疫效果评价
- Author:
WANG Lichan
- Publication Type:Journal Article
- Keywords:
Protein D(PD);
Group C meningococcal polysaccharide(GCMP);
Conjugates;
Carrier;
Humoral immunity;
Cellular immunity
- From:
Chinese Journal of Biologicals
2024;37(10):1161-1166
- CountryChina
- Language:Chinese
-
Abstract:
Objective To evaluate the immune effect of group C meningococcal polysaccharide(GCMP) conjugates using protein D(PD) of Haemophilus influenzae type b(Hib) as vector, in order to determine the feasibility of PD protein as GCMP protein vector.Methods The recombinant PD and tetanus toxin(TT) were conjugated to GCMP by 1-cyano-4-dimethylaminopyridinium tetrafluoroborate(CDAP) activation method to prepare conjugates respectively. The female BALB/c mice were subcutaneously immunized with GCMP and GCMP conjugates, which were divided into GCMP, GCMP-PD, PD, GCMP-TT,TT and negative control group(normal saline), with 12 mice in each group for 3 times of immunization. The blood samples were collected from the rim of eye before each booster immunization and 7 d after the last immunization, and the sera were separated for the detection of antibody levels and serum bactericidal assay(SBA). In addition, the spleen samples were taken7 d after the last immunization for the detection of cellular immune levels.Results The conjugates of protein and GCMP enhanced the level of anti-GCMP IgG. After the third immunization, serum anti-GCMP IgG levels in GCMP-PD and GCMP-TT groups were significantly higher than those in GCMP group(F = 5. 294 and 14. 917, respectively, each P < 0. 05), and the immune memory was produced to induce IgG1, while the IgG1 levels in GCMP-PD group were lower than those in GCMP-TT group(F = 5. 828, P < 0. 05). The levels of anti-PD IgG in serum of GCMP-PD and PD groups increased significantly after each immunization, and the levels of anti-PD IgG in GCMP-PD group were significantly higher than those in PD group after the third immunization(F = 15. 426, P < 0. 01), while those in GCMP-TT group were lower than those in TT group(F =211. 207, P < 0. 001). The results of SBA showed that the titers of bactericidal antibody in GCMP-PD group were higher than those in GCMP group(F = 11. 797, P < 0. 05), while lower than those in GCMP-TT group(F = 8. 688, P < 0. 05). The results of flow cytometry showed that the ratio of Th1 and Th2 cell subsets in GCMP-PD group had no significant difference from that in GCMP and GCMP-TT groups(F = 0. 073 and 3. 021, respectively, each P > 0. 05).Conclusion The conjugation of recombinant PD with GCMP can not only enhance the immunogenicity of polysaccharide, improve the humoral immune response, but also trigger the cellular immune response. The bactericidal effect of the immunized serum is remarkable, suggesting that PD is feasible as GCMP protein carrier.
