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M Plommet

Publications and source records attributed to M Plommet.

At least 19 recordsLinked to original sources
PubMed1991

Minimal requirements for growth of Brucella suis and other Brucella species.

Minimal nutritional requirements and temperature limits of growth were studied in Brucella suis and, comparatively, in a few other Brucella species. In a saline basic medium including thiosulphate, ammonium sulphate and glucose with addition of 2 or 4 vitamins (nicotinic acid, thiamin and panthotenic acid, biotin), 24 out of 25 B. suis, 4/6 B. melitensis and 1/6 B. abortus strains were able to grow. Some strains, however, needed to be initially induced to grow by other ingredients, CO2, other vitamins, or amino acids, or by a prolonged incubation. In the saline basic medium without ammonium, glutamic acid and/or alanine and arginine, with or without glucose, supported the growth of all the B. suis and B. melitensis strains, except 2 which required a sulphur amino acid. Five out of 6 B. abortus strains did not grow in either medium without addition of one or several aromatic amino acids or, for one strain, aspartic acid, or valine. One strain could also be induced to grow in ammonium medium by other amino acids. In a rich medium with yeast extract, all Brucella species grew at 18 degrees C and 42.5 degrees (except one) while most B. suis (14/17) grew also at 15 degrees C and 44 degrees C, in contrast to other brucellae of which a few strains only grew at these temperatures. In saline ammonium glucose medium, yeast extract at 0.1 g/l provided all the required vitamins and amino acids for all brucellae and at 1 g/l, it even provided enough nitrogen to support growth without ammonium. Such basic saline medium with yeast extract may be advantageously used in routine Brucella culture, instead of the classic undefined peptone mediums. B. suis biovar 1 strains did not differ significantly in their minimal nutritional requirements, precluding the use of these requirements to differentiate the strains, in particular the Chinese vaccine strain S2 from the reference strain 1330 or from other strains from different parts of the world. Finally, B. suis which is endowed with a nearly complete synthetic potential may represent the parental Brucella species from which the melitensis and abortus species may have evolved.

Amino Acids↗
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↗
PubMed1990

Brucella suis S2, brucella melitensis Rev. 1 and Brucella abortus S19 living vaccines: residual virulence and immunity induced against three Brucella species challenge strains in mice.

Live attenuated Brucella suis S2 vaccine was compared to living vaccines B. abortus S19 and B. melitensis Rev. 1 in mice. Residual virulence was estimated by ability to multiply and persist in spleen and lymph nodes. Immunogenicity was estimated by spleen counts of control and vaccinated mice challenged either with the reference B. abortus 544 strain or with virulent B. melitensis H38 and B. suis 1330 strains. S2 vaccine had lower residual virulence; expressed as 50% recovery time, persistence was 4.3 weeks, compared to 7.1 and 9.0 weeks for S19 and Rev. 1 vaccines. Immunity induced by the three vaccines was similar 45 days after vaccination. At 150 days, immunity by S19 and Rev.1 was still similar against the three challenge strains. In contrast, immunity induced by S2 had declined against the B. melitensis strain. Thus, a recall vaccination may be required for vaccination of sheep to confer a long-lasting immunity.

Animals↗
PubMed1989

Humoral immunity in mice mediated by monoclonal antibodies against the A and M antigens of Brucella.

All smooth strains of Brucella bear two lipopolysaccharide (LPS) antigens in a ratio that defines the classification of strains in serovars, A (A greater than M), M (M greater than A) and A.M (A = M). Anti-LPS-A monoclonal antibodies (MAb-A) were previously shown to convey protection to mice against B. abortus (A) strain 544, as shown by lower spleen counts than in controls at days 7 and 21 after challenge. Anti-LPS-M monoclonal antibodies (MAb-M) were obtained and tested for M-specificity with LPS from reference strains by ELISA, by agglutination of LPS-coated latex particles, and by inhibition of this agglutination. Antigens A and M of three strains were quantified by a homologous LPS-latex and MAb agglutination inhibition assay. Protection conferred by MAb-A and MAb-M against three strains, B. abortus 544 (A), B. abortus 292 (M) and B. melitensis H38 (M), was tested at equivalent challenge and MAb doses: intravenous challenge was adjusted to give similar infection at day 7; MAb doses were adjusted to the same specific ELISA titre. Under these conditions, MAb-A and MAb-M conferred both early and late protection, as shown at days 7 and 21, against the strains that bore the homologous major antigen, i.e., strain 544 on one hand and strains H38 and 292 on the other. In contrast, MAb directed against the minor antigen of the challenge strain conferred significant protection at day 7 only with strains 544 and H38 and no or inconsistent protection against strain 292, which expressed the lowest amount of minor antigen.(ABSTRACT TRUNCATED AT 250 WORDS)

Agglutination Tests↗
PubMed1989

Immunity to Brucella abortus induced in mice by popliteal lymph node restricted strain 19 vaccination.

Living vaccines induce immunity by lymphoid organs colonization that persists for a while before subsiding. Brucella abortus 19 vaccine injected into the footpad of mice was shown to colonize the popliteal lymph node and the spleen for at least 15 days before progressive disappearance. Administration of an immune serum before footpad vaccination restricted the colonization to the popliteal lymph node. The serum did not interfere with immunity when this immunity was measured by the virulent challenge spleen count method at least 90 days after vaccination. Immunity induced by lymph node restricted vaccination was very efficient 90 or 180 days after vaccination and was not boosted by a second injection administered 90 days after the first. This immunity was however about 20% lower, expressed in log10 spleen counts, than immunity induced by a non-restricted systemic vaccination which in addition was boosted by a recall. Restricted vaccination may mainly trigger the T-cell limb of immunity, whereas systemic vaccination triggers both humoral and cellular effectors.

Animals↗
PubMed1988

Anti-chlamydial immunity in ewes conferred by vaccination with a combination of three live chlamydia, brucella and salmonella vaccines.

Live attenuated vaccines against Chlamydia psittaci var ovis, Brucella melitensis and Salmonella abortus ovis have previously been shown to be compatible in mice by subcutaneous administration. Immunity against challenge with virulent chlamydia was, however, slightly decreased in associations including the B melitensis Rev 1 vaccine. The chlamydia strain 1B vaccine was administered to four- to five-month-old female lambs, either alone or in combination with the B melitensis Rev1 and the S abortus ovis Rv6 vaccines. Clinical, serological and bacteriological observations demonstrated the compatibility of the three vaccines. Control, singly and triply vaccinated ewes were challenged with a virulent strain of chlamydia during their second pregnancy, 15 months after vaccination. Five of the 12 control ewes lambed normally and 10 of them were infected, as shown by the excretion of the challenge chlamydia in genital secretions. Sixteen of the 17 ewes in the triple vaccine group lambed normally and none was infected. All 12 in the single vaccine group lambed normally and three of the 12 were infected. In spite of this unusually poor protection by the single vaccine, antichlamydial immunity was clearly not decreased by the association with the two other vaccines.

Animals↗
PubMed1988

Virulence of Brucella: bacterial growth and decline in mice.

Virulence may be expressed by a bacterial count in selected tissue of an animal host inoculated and autopsied in specified conditions. Time courses of splenic infection in DBA/2 mice intravenously challenged with (1) the virulent reference Brucella abortus strain 544 or with (2) the low virulent vaccinal B abortus strain 19 evidenced a one hundred times higher initial growth of the vaccine strain, followed by a steadily decrease that contrasts with the plateau phase of the virulent strain. Thus, in vivo phases of growth and decline behave independently in which immune mechanisms involved may differ.

Animals↗
PubMed1988

Reactivation of a residual Brucella abortus 19 vaccine infection in mice by a virulent challenge or by injection of brucellin or of Brucella lipopolysaccharide.

Facultative intracellular bacteria localize preferentially in reticulo endothelial system organs where they can either multiply or be destroyed, concomitantly or successively. Immunity may thus be estimated by counts of viable (surviving) bacteria at convenient time(s) after a standard challenge. When mice vaccinated with the living attenuated Brucella abortus strain 19 were intravenously challenged with the virulent B abortus strain 544, some mice exhibited unexpected high spleen counts. The vaccinal strain surviving at low level in some mice 30 days after a subcutaneous vaccination was reactivated by the virulent challenge as evidenced by a fast but temporary count increase. Reactivation was stronger in outbred OF 1 mice than in outbred CD-1 mice. Reactivation did not alter the normal course of the virulent infection as shown by comparison between mice already cured of the vaccinal infection or not, at time of challenge. Because reactivation was also induced by intravenous injection of either the brucellin allergen or the brucella lipopolysaccharide antigen, hypersensitivity reactions occurring inside the vaccinal granuloma foci may expel the surviving bacteria into the surrounding extracellular environment where a secondary growth may develop.

Allergens↗
PubMed1987

Simultaneous vaccination by three living attenuated strains of Brucella, Salmonella and Chlamydia in mice.

Associations of vaccines for simultaneous administration were successfully developed long ago, in particular in human medicine, although there have been very few attempts to associate living bacterial vaccines. Unfortunately, living vaccines can interact with one another resulting in either a virulent infection or an exclusion of one by the other. Having developed two new low virulence vaccinal strains of Chlamydia psittaci var. ovis and Salmonella abortus ovis for use in veterinary medicine, we studied associations of both and with the Brucella melitensis Rev1 vaccine in mice. There was no interaction between the Chlamydia and the Salmonella vaccines and between the Salmonella and the Brucella vaccines from the point of view of immunogenicity. In contrast, anti-Chlamydia immunity was decreased by about 15-19% when the Chlamydia vaccine was associated with the Brucella vaccine in double or triple association. Surprisingly, the Chlamydia vaccinal strain infection was slightly extended when administered in association. The simultaneous vaccination we tested could be of great interest in veterinary medicine, but special attention must be devoted to anti-Chlamydia immunity and would have to be studied in a ewe model.

Animals↗
PubMed1987

Anti-Brucella cell-mediated immunity in mice vaccinated with a cell-wall fraction.

Immunity against Brucella, a facultative intracellular bacteria, can be induced in mice by live or by killed-whole-cell or fraction vaccine. This immunity can be adoptively transferred from live vaccinated donor to recipient mice, or passively with immune serum raised against bacterial fractions. A protein-bound peptidoglycan fraction (PG) was used to immunize DBA/2 donor mice intravenously or subcutaneously in the hind footpads. Splenic or popliteal lymph nodes cells were transferred to recipients that were intravenously challenged with a B abortus virulent strain. Brucella spleen counts, and in some cases liver counts, were done 15 days later or at successive times. Spleen cells depleted from macrophages and lymph nodes cells conferred immunity to recipients. This immunity increased after transfer for about 21 days. Lymph nodes cells were more efficient to transfer immunity than spleen cells. This immunity was abated but not abrogated by treatment of cells by anti-Thy serum and was transferred by both nylon wool non adherent (T enriched) or adherent (B enriched) cells. Comparative transfer experiments with DBA/2 versus CBA mice, live vaccine versus PG fraction vaccine, virulent versus avirulent (vaccinal) challenge evidenced that the three factors were involved in induction and/or expression of immunity. DBA/2 mice responded better to fraction vaccine and virulent challenge whereas CBA responded better to live vaccine and to avirulent challenge strain. In contrast DBA/2 X CBA F1 responded equally well against the virulent challenge to transfer of cells from live vaccine or PG fraction vaccinated donor mice. Two cell-mediated immune mechanisms may thus be involved in transferred immunity the expression of which may be genetically determined.

Animals↗
PubMed1987

T cell mediated and humoral immunity in a mouse Chlamydia psittaci systemic infection.

Immunity against Chlamydia psittaci, an obligate intracellular parasite, was studied in a mouse model of systemic infection. Sera (0.1 ml) and splenic cells (2 X 10(8)) from immunised mice were given intravenously to susceptible mice 16 hours before intravenous challenge with 1 X 10(5) plaque forming units (pfu) of virulent strain AB7. Transfer of immune cells primed with virulent strain AB7 or vaccinal strain 1B, lowered splenic and hepatic colonisation by approximately 5.5 log pfu. Treatment of immune cells with antithymocyte serum plus complement, before transfer, abrogated the protection. Transfer of sera raised against the virulent strain AB7, or the attenuated vaccinal strain 1B, lowered hepatic colonisation by approximately 1.5 log pfu. Sera containing antigenus antibodies, raised against heat-killed chlamydiae from strain AB7 or the non-virulent intestinal strain iB1, were not protective. Cellular immunity is mainly responsible for the observed protection, although humoral immunity may play some role.

Animals↗
PubMed1986

[Anti-Brucella immunity transferred by immune serum and that transferred by splenic lymphocytes cannot be added].

Immune serum and spleen cells from mice vaccinated with a cell-wall fraction (PG) from Brucella were previously shown to transfer a good protection to mice against a virulent Brucella challenge. This protection estimated by spleen and liver time-course infection was similar to that afforded by vaccination. In present experiments, DBA/2 mice were first transferred with either immune serum from infected mice, splenic cells from mice intravenously vaccinated with PG fraction 28 days previously, or both immune serum and splenic cells. In this case, the serum was either injected before the challenge, as were the splenic cells, or 2 days after it in order to reduce the lowering effect of the serum on level of initial colonization of the spleen. The transferred mice were then intravenously challenged with the virulent strain B. abortus 544 and liver and spleen counts were performed on groups of five mice weekly up to six weeks. Immune serum and splenic cells from vaccinated mice were again shown to strongly reduce the time-course of splenic infection. However addition of both effects was observed for a short time only two and three weeks post-challenge and only when the serum was injected after the challenge. In contrast, no additive or even an antagonistic effect was observed after the 21st day. Liver infection was not notably modified by both immune serum or splenic cells (except increment of initial colonisation by serum) until the 21st day when both helped reduce the course of infection. However again no additive effect was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Theoretical, practical and statistical basis for a general control method of activity for anti-Brucella vaccines.

Lots of five weeks old female CD-1 mice were vaccinated at several doses with living (B. abortus 19), killed whole cells or purified fractions vaccines. The doses were the number of bacterial cells injected per mouse, either viable (living vaccines), total (killed) or number calculated from the yield of extraction. The mice were intraperitoneally injected with a lyophilized standard challenge, 2 X 10(5) Brucella abortus 544, thirty days after vaccination. In two assays, B. melitensis H.38 was used as challenge at several doses. Responses to a good live vaccine were dose independent. Responses to killed whole cell and purified fractions were usually dose dependent. A reference lyophilized vaccine previously prepared and titrated would give the reference response to one unit. These data can be used to devise a general control method of activity for anti-Brucella vaccines. This was proposed and discussed in the preceding paper.

Animals↗