Protection of BALB/C mice against Brucella abortus 544 challenge by vaccination with combination of recombinant human serum albumin-l7/l12 (Brucella abortus ribosomal protein) and lipopolysaccharide.
BACKGROUND
The immunogenic Brucella abortus ribosomal protein L7/L12 and Lipopolysaccharide (LPS) are promising candidate antigens for the development of subunit vaccines against brucellosis.


OBJECTIVE
This study was aimed to evaluate the protection of combination of recombinant HSA-L7/L12 fusion protein with LPS in Balb/c mouse.


METHODS
The recombinant HSA-L7/L12 fusion protein in Saccharomyces cerevisiae was expressed and purified by affinity chromatography column. LPS was extracted by n-butanol, purified by ultracentrifugation. BALB/c mouses were immunized in 9 groups with PBS, HSA, tHSA-L7/L12, L7/L12, LPS, LPS+ HSA, LPS+ tHSA-L7/L12, LPS+ L7/L12, B. abortus S19. ELISA, LTT tests and challenging two weeks after last injection were carried out. Bacterial count of spleen of immunized BALB/c mouse was done four weeks after challenging with virulent strain B. abortus 544.


RESULTS
In ELISA test the specific antibodies of tHSA-L7/L12 exhibited a dominance of immunoglobulin IgG1 over IgG2a. LPS-HSA and tHSA-L7/L12 + LPS produced a significantly higher antibody titer than LPS alone and L7/L12+LPS (P < 0.05). The predominant IgG subtype for LPS and L7/L12+LPS were IgG3. However, tHSA-L7/L12+ LPS and LPS+ HAS elicited predominantly IgG1 and IgG3 subtypes. In addition, the tHSA-L7/L12 fusion protein and L7/L12 elicited a strong T-cell proliferative response upon restimulation in vitro with recombinant tHSA-L7/L12 and L7/L12, suggesting the induction of a cellular immunity response in vivo. However, there was no significant difference proliferative response in L7/L12 and tHSA-L7/L12 fusion protein (P > 0.05). The combination of tHSA-L7/L12 fusion protein with LPS and B. abortus S19 induce higher level of protection against challenge with the virulent strain B. abortus 544 in BALB/c mice than other groups (P = 0.005).


CONCLUSIONS
The combination of tHSA-L7/L12 fusion protein with LPS had higher protective ability than LPS and fusion protein distinctly.
Department of Microbiology, Ilam University of Medical Sciences, Ilam, Iran. pakzad_i2006@yahoo.com
Iraj
I
Pakzad
Abbas
A
Rezaee
Mohammad J
MJ
Rasaee
Ahmad Zavaran
AZ
Hossieni
Bahman
B
Tabbaraee
Anoshirvan
A
Kazemnejad
D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000818:Animals; D001426:Bacterial Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D002004:Brucella Vaccine / Q000008:administration & dosage / Q000235:genetics* / Q000276:immunology*; D002003:Brucella abortus / Q000276:immunology*; D002006:Brucellosis / Q000517:prevention & control*; D005260:Female; D006801:Humans; D007274:Injections, Intraperitoneal; D008070:Lipopolysaccharides / Q000008:administration & dosage / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D012269:Ribosomal Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D012709:Serum Albumin / Q000276:immunology; D014611:Vaccination; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology
D000276:Adjuvants, Immunologic; D001426:Bacterial Proteins; D002004:Brucella Vaccine; D008070:Lipopolysaccharides; D011993:Recombinant Fusion Proteins; D012269:Ribosomal Proteins; D012709:Serum Albumin; D014614:Vaccines, Synthetic; C016700:ribosomal protein L7-L12