Biomedical subjects
F Peraldi
Publications and source records attributed to F Peraldi.
The thing for Freud and the Freudian thing.
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Biological properties of a panel of murine monoclonal anti-Brucella antibodies.
Immune sera have previously been shown to play a positive role in immune protection against murine experimental brucellosis. The protective properties of a panel of five anti-Brucella monoclonal antibodies (Mabs) were therefore assessed by estimation of the acceleration of the blood clearance of intravenously inoculated Brucella and of the reduction of splenic infection on Day 7 after infection. Three 'strongly protective', one 'weakly protective' and one 'non-protective' Mabs were identified. As a first step towards the study of the mechanism of this humoral protection, these Mabs were further compared for structural and functional properties such as immunoglobulin isotype, anti-Brucella specificity, anti-Brucella in vitro bacteriostasis, Brucella agglutination and complement fixation when complexed with tyndallized Brucella. No correlation was found between protection and either agglutination or direct bacteriostasis. On the other hand, the results observed suggest that isotypes (and especially the IgG2a isotype) could play an important role in in vivo immuno protection and that complement may be involved. However, the fact that one of the protective Mabs belongs to the IgA isotype, does not cross-react with the others in anti-Brucella epitopic specificity and does not fix complement underlines the probable diversity of the mechanisms involved.
Two sensitive assays for the detection of anti-Brucella antibodies.
A laser-nephelometric assay (LNA), applied to an adapted Wright's agglutination technique and an immunoenzymatic assay (ELISA) on tyndallised and sonicated Brucella are described. Both lead to an increased sensitivity of previous techniques for the detection of anti-Brucella antibodies. This was assessed in a) Brucellosis patients with either Wright and/or IF positive reactions (sero-positive) or Wright and IF negative reactions (sero-negative, ancient brucellosis). Positive results were obtained in all cases with a highly significant increase of the titers observed in "sero-positive" patients. b) Normal subjects with no previous history and no biological stigmata of brucellosis: most sera gave negative results - a very low incidence of weakly positive results were however evidenced. c) Subjects vaccinated with fraction PI: positive results were observed in all cases. They were much earlier detected with LNA or ELISA than with Wright's or IF tests and the ELISA or LNA titers of late "sero-positive" sera were 3 to 36 times higher than Wright's titers. d) Supernatants of anti-Brucella hydridomas: LNA and ELISA were both successfully applied to the screening of such supernatants.
Induction of autoantibodies and circulating immune complexes in mice after injection of Brucella fraction "PI" or inoculation with live Brucella suis.
"PI", a vaccinating fraction with B mitogenic and polyclonal activator (PCA) activity extracted from Brucella melitensis, was i. p. injected into B6 and DB mice. In B6 mice, this led to an important but transient increase in the level of anti-ssDNA antibodies, the induction of rheumatoid factor (RF) and the appearance of circulating immune complexes (CIC). In DB mice, on the other hand, the only significant effect consisted of a slight and ephemeral peak of CIC in sera from day 7. Similarly, while i. v. inoculation of live B. suis did not influence the levels of anti-ssDNA, RF or CIC in DB mice, in the B6 mice it exerted effects which were comparable to those of PI but considerably weaker, more transient and somewhat delayed. These results are discussed in terms of the importance and significance of strain-dependence for the induction of autoimmune phenomena by PCA and microbial infections.