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Y Le Garrec

Publications and source records attributed to Y Le Garrec.

8 recordsLinked to original sources
PubMed1979

Resistance to tumor graft in mice treated with inactivated Brucella abortus cultured in smooth or rough phase.

Because killed Brucella abortus organisms cultured in smooth (S) or rough (R) phase were known to differentially influence humoral and cellular immune responses and to differ in their effects on T-dependent responses, the antitumor properties of killed B. abortus organisms, cultured in S- or R-phase and then inactivated, were compared in (C57BL/6 X DBA/2)F1 female mice with the use of 6 different transplantable tumors. In solid tumors, the antitumor effects produced by S-preparations were never improved by R-preparations. However, in ascites tumors, R-preparations gave the best antitumor results. These findings suggested that the defense mechanisms acrivated by immunostimulants may differ according to the site of tumor implantation. Among the other experimental factors studied, the route of B. abortus administration had a prominent role. Local injection at the site of tumor implantation before or after the graft gave better results than did systemic treatment. Systemic treatment could enhance the growth of Lewis tumor when applied 5 or 10 days before tumor graft but generally had an antitumor effect when given 1 day after the graft.

Animals↗
PubMed1978

Influence of the antigenicity of Brucella preparations on modulation of the immune response to sheep erythrocytes.

The relationship between the expression of surface antigenicity of inactivated Brucella and the immunostimulant properties on the sheep erythrocyte response was studied in mice. The agglutinogenic Brucella abortus B19S preparation was compared to two non-agglutinogenic preparations (B19R and PB), using the plaque-forming and rosette-forming cell tests. When Brucella and antigen were injected together, only non-agglutinogenic preparations, even used at low doses, were able to increase the plaque-forming and rosette-forming cell responses measured 4 days after immunization. When the interval between the previous injection of non-agglutinogenic preparations and that of the antigen increased or when they were injected 24 h after the antigen, the modification of those two responses was no longer observed. After day 4, for the simultaneous injection of Brucella and antigen, B19S and PB preparations induced the best responses; this effect was dose dependent. Thus, in the present experimental situation, the modification of the day 4 response appeared independent of those of the ensuing days.

Agglutination↗
PubMed1978

Modulation of immune response by killed Brucella abortus organisms: comparison of the effects of smooth and rough strains on T-dependent responses.

Inactivated Brucella abortus organisms of the smooth (S) or rough (R) strain were tested comparatively on two T-dependent immune responses: mixed-lymphocyte reaction and delayed-type hypersensitivity. The intravenous injection of S organisms depressed the two tests, whereas R organisms increased mixed-lymphocyte reaction and did not alter delayed-type hypersensitivity significantly. This observation may be helpful in understanding the differences in adjuvant properties of S and R brucellae.

Brucella abortus↗
PubMed1976

[Influence of the mouse genotype on the sensitivity to Brucella abortus 544].

The susceptibility to brucella infection (Brucella abortus 544) of different inbred mice and outbred CD1 strains has been studied. The degree of infection was determined on days 7 and 11 after challenge. The CBA and DBA2 strains showed greater susceptibility and homogeneity compared to the other strains (C57B16, C3H, C57B16 x DBA2) and to the CD1 mice. The kinetics of infection in DBA2 and CBA, compared to those of the CD1 for a longer period, show that the degree of infection decreases rapidly after 11 days. However, 90 days after challenge, the level of infection in DBA2 mice remains higher than in CBA and CD1. The DBA2 strain seems able to provide an improvement for anti-brucella vaccine control.

Animals↗
PubMed1976

[Evaluation of antibrucellosis vaccines using guinea pigs].

In the preliminary stage of a global study made in our laboratory to compare the control technics of antibrucella vaccines (abortus) both in mice and guinea pigs, we have studied the kinetics of brucella infection in the Hartley guinea pig after various doses of Brucella abortus strain 544. Two trials have been carried out: the first with 5000 and 10000 bacteria and the second with 5000, 10000 and 30000 bacteria. The results obtained allow to envisage the use of a challenge dose of at least 10000 bacteria (instead of 5000) and the sacrifice of animals at the 4th week (a gain of two weeks compared to the present protocol).

Animals↗
PubMed1976

[Brucella and modification of the host response to bacterial and viral infection. Effect of the S-R variation].

Within the framework of a study on the immunostimulant properties of Brucella abortus and of its extracts, we have investigated the protective activity on infection of mice by Klebsiella pneumoniae and on Charlotte Friend's leukemia, of inactivated Brucella abortus and brucella lysates by ultrasound. The injection of inactivated B 19 R preparations and their lysates three days before infection by klebsiella has allowed to protect mice against a large number of DL50 (100 and 1000 in certain cases). To determine the role of the surface antigen in this type of immunostimulant, the activity of the B 19 R inactivated preparations has also been examined. It appears that the protection obtained by the injection on day J + 3, in relation to the infection, does not depend on the presence of the complete surface antigen, while the long term effect seems to be more dependent on this. The development of Charlotte Friend's leukemia has been favourably influenced by the previous injection of B 19 S or inactivated B 19 R. Immunotherapy on days J + 1 or J + 3 gave encouraging results with B 19 R, but facilitation with B 19 S. These results confirm the immunostimulant activity of brucella which has already been reported by ourselves and by other authors.

Animals↗