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I Jacques

Publications and source records attributed to I Jacques.

10 recordsLinked to original sources
PubMed1995

Immunogenic properties of Brucella melitensis cell-wall fractions in BALB/c mice.

The immunogenicity of several Brucella melitensis cell-wall (CW) fractions was tested in BALB/c mice. These CW fractions were smooth lipopolysaccharide (S-LPS) fraction from smooth (S) B. melitensis strain 16M, sodium dodecyl sulphate-insoluble (SDS-I) CW fraction from B. melitensis strain 16M (S) undigested or digested with pepsin, and SDS-I CW fraction from rough (R) B. melitensis strain H38. The B. melitensis SDS-I CW fraction contained two major outer-membrane proteins (OMPs) of 25-27 kDa and 31-34 kDa, peptidoglycan (PG) and a small quantity (1.5%) of LPS. One month after immunisation, mice were challenged with virulent B. melitensis strain H38 (S) and Brucella spleen counts were recorded on days 28 and 49 after challenge. Before challenge, as measured by ELISA, the highest antibody responses to S-LPS were observed in mice immunised with SDS-I CW fraction from B. melitensis strain 16M (S), whether digested with pepsin or undigested. All immunised mice, except those immunised with the SDS-I CW fraction from the R strain, showed higher IgG1 than IgG2a antibody responses to S-LPS (IgG1:IgG2a ratio 3.64-7.71). Antibody responses to the 25-27-kDa OMP were very low, with the highest responses in the mice immunised with the SDS-I CW fraction from the R strain. These results indicated that, in BALB/c mice, these CW fractions probably induced Th2-dependent more than Th1-dependent antibody responses.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Protection conferred on mice by combinations of monoclonal antibodies directed against outer-membrane proteins or smooth lipopolysaccharide of Brucella.

The effect of monoclonal antibodies (MAbs) injected alone or in combination on brucella splenic infection in CD-1 mice was tested 7 and 21 days after a challenge with virulent Brucella abortus 544. Passive immunisation of mice with anti-25-27-kDa MAb alone, or mixed with protective anti-16.5 and anti-36-38-kDa MAbs, or with MAbs of the same specificity which were previously demonstrated to have no activity on CD-1 mice, produced a significant reduction of spleen counts of B. abortus (p less than 0.01). Other combinations of MAbs did not reduce splenic infection in comparison with the untreated control group. BALB/c mice were used to test the possible interference of the immune response of CD-1 mice against MAbs that were produced in BALB/c mice. No reduction of splenic infection was shown with anti-25-27- or -36-38-kDa MAbs, whereas anti-lipopolysaccharide (LPS) MAb which was produced in CBA mice was effective. Combination of anti-protein MAbs with the anti-LPS MAb produced only the effect of the anti-LPS MAb at 7 and 21 days after challenge.

Animals↗
PubMed1992

Protection against Brucella melitensis or Brucella abortus in mice with immunoglobulin G (IgG), IgA, and IgM monoclonal antibodies specific for a common epitope shared by the Brucella A and M smooth lipopolysaccharides.

Mice passively immunized prior to a challenge infection with immunoglobulin G (IgG) and IgM monoclonal antibodies (MAbs) specific for a common epitope of both A- and M-dominant strains had viable Brucella abortus 544 or Brucella melitensis H38 counts in the spleen reduced to the same extent as did mice passively immunized with MAbs specific for either the A or the M epitope. The IgA MAb was not effective.

Animals↗
PubMed1991

Induction of antibody and protective responses in mice by Brucella O-polysaccharide-BSA conjugate.

A Brucella conjugate vaccine was synthesized by covalently coupling the O-polysaccharide (PS) obtained from Brucella melitensis 16M, to bovine serum albumin (BSA). The conjugate (PS-BSA) was non-toxic for mice. When injected at two doses (10 or 1 micrograms) in mice, it induced the production of antibodies and the boost was shown to be efficient if administered after 10 weeks. Immunization of mice with 10 micrograms of conjugate conferred significant protection against virulent challenge with B. melitensis H38, similar to that obtained with the reference vaccine H38.

Animals↗
PubMed1991

Escherichia hermannii (ATCC 33651) polysaccharide-protein conjugates: comparison of two conjugation methods for the induction of humoral responses in mice.

Escherichia hermannii (ATCC 33651) LPS O-polysaccharide was covalently linked to a carrier (bovine serum albumin) to form conjugates either directly or with a spacer arm (adipic acid dihydrazide). The immunogenicity of both conjugates at three different doses was tested in mice. Antibodies to the conjugate were produced and were shown to react with free lipopolysaccharide. The directly-coupled conjugate was found to be more immunogenic than the indirect one (i.e. lower dose necessary for a similar response). The antibody response elicited by the directly coupled conjugate (1 microgram/animal) began at 21 days and was sustained for at least 4 months. The mouse model described here may be applicable to the testing of other conjugates composed of bacterial cell wall polysaccharides and LPS O-chains.

Animals↗
PubMed1991

Protection conferred on mice by monoclonal antibodies directed against outer-membrane-protein antigens of Brucella.

Twenty-six monoclonal antibodies (MAbs) directed against seven brucella outer-membrane proteins (OMPs) of 10, 16.5, 19, 25-27, 31-34, 36-38 and 89 Kda were screened for passive protection of mice; three MAbs (directed against 16.5, 25-27 and 36-38 Kda) reduced significantly the initial colonisation of the spleen measured 7 days after challenge. Although significant, the reduction in numbers of Brucella organisms in the spleen was low compared with that conferred by MAbs against lipopolysaccharide of smooth specificity (S-LPS). The three most protective MAbs belonged to two isotypes (IgG1 and IgG2a) and were specific for three different OMPs. No relationship between protection and binding of MAbs to the challenge S strain or its rough mutant was observed in the mouse model. The humoral protection depended mainly on antibodies directed against S-LPS, although some MAbs against OMPs had weak protective activity.

Animals↗
PubMedDate not supplied

Monoclonal antibodies to Brucella rough lipopolysaccharide: characterization and evaluation of their protective effect against B. abortus.

We characterized 4 monoclonal antibodies (mAb) specific for rough lipopolysaccharide (R-LPS) of Brucella. mAb were selected by enzyme-linked immunosorbent assay (ELISA) on whole B. abortus 45/20 rough cells and R-LPS from B. melitensis B115 rough cells. Specificity was confirmed by immunoblot analysis using R-LPS and smooth LPS (S-LPS) preparations. Anti-R-LPS revealed the low molecular mass R-LPS molecules below 20.1 kDa in the R-LPS and S-LPS preparations as well as the typical A and M patterns in high molecular mass S-LPS molecules (between 21.5 and 66 kDa) in the S-LPS preparations. An O-polysaccharide-specific mAb revealed only high molecular mass S-LPS molecules in the S-LPS preparation. In ELISA the anti-R-LPS mAb bound better on rough than on smooth B. abortus 544 whole cells, and this was confirmed by immunoelectron microscopy. Protective activity of anti-R-LPS mAb of different isotypes was tested on mice and compared with an S-LPS-specific mAb. Only the IgG3 mAb reduced significantly the splenic infection but did not reach the level of protection conferred by the S-LPS-specific mAb.

Animals↗
PubMedDate not supplied

Planning ahead.

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Hospital Restructuring↗
PubMedDate not supplied

The right fit.

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Aged↗