title: [Mouse macrophage-derived chemokine as an adjuvant enhances the protective effect of P6 protein vaccine of nontypeable Haemophilus influenzae].
abstract: OBJECTIVE
  To express P6 protein of nontypeable Haemophilus influenzae (NTHi) in prokaryotic cells and observe the immune effect of macrophage-derived chemokine (MDC) as an adjuvant on NTHi-P6 protein vaccine.
  
  
  METHODS
  The encoding sequence of NTHi-P6 protein was inserted into plasmid PGEX-6P2, and the recombinant plasmid PGEX-6P2/P6 was transformed into E.coli XL1-Blue. In the expression system, the P6 protein was induced and expressed. BALB/c mice were randomized into three groups that were respectively inoculated intraperitoneally with P6 protein combined with Freund's adjuvant and MDC, P6 protein combined with Freund's adjuvant and only PBS, 3 times at 0, 14 and 28 days, respectively. Sera were collected from 12 mice of each group 14 days after each injection. The titer of IgG antibodies was detected by ELISA. Splenocytes were isolated from 3 mice of each group for determining the levels of IL-4 and IFN-γ by ELISA. Furthermore, the other 15 mice of each group were challenged with 10×LD50 NTHi ATCC49247 to observe the protective effect of the vaccine.
  
  
  RESULTS
  The IgG antibody could be induced by p6 protein combined with Freund's adjuvant and MDC and P6 protein combined with Freund's adjuvant, and the titers were 1:1 140.25 and 1:3 044.38, respectively. The differences in the antibody titers and the levels of IFN-γ between the two groups were significant statistically (P<0.05). There was no difference in IL-4 levels between the two groups (P>0.05). After challenged with 10×LD50 NTHi ATCC49247, the survival rate of mice in P6 protein combined with Freund's adjuvant and MDC group was 80%, and significantly higher than that in the PBS group (P<0.05), but no statistical difference was noted when compared with P6 protein combined with Freund's adjuvant group.
  
  
  CONCLUSIONS
  MDC as an adjuvant could enhance the immune protective effect of NTHi-P6 protein vaccine to an extent.
authors.affiliation: Department of Microbiology, Hebei North University, Zhangjiakou 075000, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Han
authors.affiliation: Department of Microbiology, Hebei North University, Zhangjiakou 075000, China.
authors.forename: Chenhong
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Microbiology, Hebei North University, Zhangjiakou 075000, China.
authors.forename: Haixia
authors.initials: H
authors.lastname: Qiao
authors.affiliation: Department of Microbiology, Hebei North University, Zhangjiakou 075000, China.
authors.forename: Yanxia
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Microbiology, Hebei North University, Zhangjiakou 075000, China.
authors.forename: Yueli
authors.initials: Y
authors.lastname: Chang
authors.affiliation: Department of Microbiology, Hebei North University, Zhangjiakou 075000, China.
authors.forename: Yutuo
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology*; D054422:Chemokine CCL22 / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005620:Freund's Adjuvant / Q000008:administration & dosage / Q000276:immunology; D006192:Haemophilus Infections / Q000276:immunology* / Q000382:microbiology / Q000517:prevention & control; D018073:Haemophilus Vaccines / Q000008:administration & dosage / Q000276:immunology*; D006193:Haemophilus influenzae / Q000276:immunology* / Q000502:physiology; D054884:Host-Pathogen Interactions / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007371:Interferon-gamma / Q000276:immunology / Q000378:metabolism; D015847:Interleukin-4 / Q000276:immunology / Q000378:metabolism; D008807:Mice, Inbred BALB C; D011897:Random Allocation; D013154:Spleen / Q000276:immunology / Q000378:metabolism; D016019:Survival Analysis; D013997:Time Factors
chemical_list: D000276:Adjuvants, Immunologic; D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D054422:Chemokine CCL22; D018073:Haemophilus Vaccines; D007074:Immunoglobulin G; C069990:P6 outer membrane protein, Haemophilus; D015847:Interleukin-4; D007371:Interferon-gamma; D005620:Freund's Adjuvant