Immunogenecity of synthetic peptides representing linear B-cell epitopes of VapA of Rhodococcus equi.
Amino acid 65-78 of membrane protein VapA of the facultative intracellular Rhodococcus equi contained an immunodominant N-terminal B-cell epitope (N15Y peptide). Safety and immunogenecity of a synthetic peptide consisting of the amino acid 65-78 of VapA (peptide N15Y) were evaluated first in mice and in healthy adult horses. A single dose of a peptide-VapA vaccine induced and only in presence of adjuvant, specific IgG antibodies in sera of mice. After challenge with virulent R. equi 3 weeks after immunization, tissue clearance was more delayed in immunized mice than in control mice. An antibody-mediated response (restricted to IgG1 and IgG2b subclasses) predominated in vaccinated mice sera and no specific lymphocytes proliferation was observed. Next, a total of 15 mares were given systemic inoculation of N15Y peptide with IMS3012 ( n = 4 ) or IMS2211 ( n = 4 ) or ISA35 ( n = 4 ) or placebo ( n = 2). Serological responses to the peptide vaccine were found in all but not in placebo group. A significant increase of IgGb subclass in sera of vaccinated mare with N15Y peptide in presence of IMS3012 was observed in comparison to IMS2211 or ISA35 or control group. Moreover, INF-gamma, IL-2 and IL-10 mRNA expression increased more significantly in peripheral blood lymphocytes of IMS3012 group than in IMS2211 or ISA35 group. Interestingly, a significant decrease of IL-4 mRNA expression (undetectable level) was observed with all adjuvants. These results support the use of peptide N15Y in presence of IMS3012 adjuvant in future studies of protection of foals against R. equi.
AFSSA. Laboratoire d'études et de recherches en pathologie équine.IPC, Goustranville 14430, Dozulé, France. s.taouji@dozule.afssa.fr
Saïd
S
Taouji
Izumi
I
Nomura
Steeve
S
Giguère
Seiji
S
Tomomitsu
Tsutomu
T
Kakuda
Vincent
V
Ganne
Shinji
S
Takaï
D000193:Actinomycetales Infections / Q000276:immunology* / Q000662:veterinary*; D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology*; D001428:Bacterial Vaccines / Q000276:immunology*; D015153:Blotting, Western; D002455:Cell Division / Q000502:physiology; D016207:Cytokines / Q000096:biosynthesis; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000096:biosynthesis; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000235:genetics / Q000276:immunology*; D005260:Female; D006734:Horse Diseases / Q000276:immunology*; D006736:Horses / Q000276:immunology*; D007114:Immunization; D007118:Immunoassay; D007074:Immunoglobulin G / Q000032:analysis / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D012329:RNA, Bacterial / Q000096:biosynthesis / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016929:Rhodococcus equi / Q000235:genetics / Q000276:immunology*; D022223:Vaccines, Subunit / Q000138:chemical synthesis / Q000235:genetics / Q000276:immunology; D037521:Virulence Factors / Q000235:genetics / Q000276:immunology*
D000276:Adjuvants, Immunologic; D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D016207:Cytokines; D017931:DNA Primers; D018076:DNA, Complementary; D000939:Epitopes; D007074:Immunoglobulin G; D012329:RNA, Bacterial; D022223:Vaccines, Subunit; D037521:Virulence Factors