Guy Bordenave

Louis Pasteur (1822–1895)

In Louis Pasteurs scientific career it is striking to note the exponential character of the research he introduced in all the fields he opened up. He offered fabulous opportunities to stereochemistry. He is acknowledged as one of the founders of microbiology. He established the possibility of anaerobic life. He pointed the way to epidemiology, public health, and the bacteriologic fight. He struggled against the idea of spontaneous generation of life. He irrevocably substantiated the microbial theory of infectious diseases. He demonstrated that bacterial virulence could be attenuated, he evidenced immunity and generalised the vaccination principle. He also was an incomparable experimenter.

A reverse hemolytic plaque assay for the detection and the enumeration of immunoglobulin allotype-secreting cells

Abstract We describe a reverse hemolytic plaque assay to enumerate rabbit immunoglobulin allotype-secreting cells. This technique makes use of sheep red blood cells (SRBC) sensitized with goat anti-rabbit IgG and rabbit anti-allotypic sera as revealing antisera. We have used the assay to compare at the IgG molecule level and at the immunoglobulin allotype-secreting cell level, the preferential expression (pecking order), in heterozygous rabbits, of one of the two alleles either at the a or the b locus, respectively, governing the a series allotypic specificities carried by the variable region of the heavy chains and the b series allotypic specificities essentially carried by the constant region of the K light chains.

Characteristics of the antigenic determinants revealed by hybridoma-made monoclonal antibodies against the Fc fragment of rabbit IgG

Abstract We studied 7 monoclonal antibodies produced by mouse hybridoma directed against the Fc fragment of rabbit IgG. Five of them recognized different antigenic determinants mostly borne by the CH3 domain. These antibodies seemed to distinguish some populations of IgG by precipitation in gel but not by radioimmunoadsorption. One monoclonal antibody probably recognized the e15 allotypic determinant. Some monoclonal antibodies recognized an ancestral isotypic determinant which has been preserved during evolution and is present on man, calf and rabbit IgG molecules.

Epitope complementarity and idiotypic interactions: A study of idiotypic-like interactions between anti-cytidine and anti-guanosine A/J mouse monoclonal antibodies—I. Characterization of these interactions

Idiotypic-like interactions between mAbs directed against cytidine (Cyd) or guanosine (Guo) nucleosides were characterized. These mAbs, Cyd-1 (IgG2b, kappa), Guo-1 (IgG1, kappa) and Guo-2 (IgG1, kappa) were derived from splenocytes of A/J mice immunized with Cyd-KLH or Guo-KLH and recognized the nucleoside base moieties involved in hydrogen bonding. The interactions between Guo-1 or Guo-2 and Cyd-1 involved cross-reactive or distinct-but-neighboring paratope-associated idiotopes. These interactions were characterized by KD values of 4.6 x 10(-6) and 1.8 x 10(-6)M, respectively. The three anti-nucleoside mAbs exhibited Ab2 beta properties and manifested epibody (Ab2 epsilon) activity towards ssDNA. We compared these idiotypic-like reactivities with the anti-idiotypic activity of an intentionally induced IgG1, kappa anti-idiotype mAb prepared with splenocytes from A/J mice immunized with Cyd-1. This Ab2 antibody which bound to Cyd-1 with a KD of 1.1 x 10(-9) M, manifested an Ab2 gamma activity, i.e. it recognized a paratope-associated idiotope on Cyd-1 without exhibiting Ab2 beta properties. In addition, the anti-(Cyd-1) completely inhibited (Cyd-1)-(Guo-1) and (Cyd-1)-(Guo-2) interactions.

L'idiotypie comparée des anticorps de lapins différents contre salmonella abortus-equi et contre le virus de la mosaique du tabac. observation d'une réactivité croisée entre certains idiotypes d'anticorps contre ces deux matériels antigéniques†

Idiotypic determinants of anti‐tabacco mosaic virus (TMV) antibodies produced by different rabbits can sometimes show a very strong similarity. The frequency of precipitin reactions between sera against anti‐TMV idiotypes and anti‐TMV sera which are not used for their preparation (heterologous reactions) is about 4 %.

Tetraparental rabbits chimeric for their lymphoid system—I. Allotype expression

We constructed tetraparental rabbits by immunosurgically prepared inner-cell-mass transplantation. The two constitutive parental strains were chosen so that they not only differed by their coat colour (brown and white rabbits) but also by the allotypic specificities of their immunoglobulins. It was thus possible to distinguish among the rabbits born from composite blastocysts those which were chimeric for their lymphoid system and to unambiguously quantitate the respective contribution of each parental strain to this chimerism. In this peculiar situation, the possible perturbation of the expression of immunoglobulin allotypic specificities could be tested. Thus further analysis of the tetraparental rabbits immunoglobulins was performed to look at possible anomalies of their constitution. In only one out of the 20 tetraparental rabbits studied, we found IgG having heavy chains with the allotypic specificities of one parental strain and light chains with the allotypic specificities of the other parental strain. We did not observe, in any case, the expression of immunoglobulin allotypic specificities other than the expected ones. We always observed a marked decrease with time in the expression of the immunoglobulins produced by the lymphocytes of one parental strain accompanied by a concomitant increase in the expression of the immunoglobulins produced by the lymphocytes of the other parental strain. Two tetraparental rabbits were found to be germ-line chimeras. Analysis of the immunoglobulin allotypic specificities of the progeny of our tetraparental rabbits including these two did not reveal any perturbation in their hereditary transmission according to the usual Mendelian laws.

Role of CD40 in a T Cell-Mediated Negative Regulation of Ig Production

To investigate the possible role of CD40 in a negative regulation of Ig production, we used the mouse Ig allotype suppression model. T splenocytes from Igha/a mice are able in vivo to totally and chronically inhibit the production of IgG2ab (IgG2a from the Ighb haplotype). Accordingly, postnatal transfer of Igha/a T splenocytes into histocompatible Igha/b F1 or congenic Ighb/b mice leads to a characteristic IgG2ab suppression. The helper action of anti-IgG2ab CD4+ T cells is required for the recruitment of anti-IgG2ab CD8+ T suppression effectors. The latter use perforin (pore-forming protein, Pfp)- and/or Fas-dependent cytotoxic pathways to continuously eliminate B cells recently committed to IgG2ab production. In the present study we first showed that in vivo agonistic anti-CD40 mAb treatment of Igha/a mice, deprived of their CD4+ T cell compartment, could bypass the help of Ig allotype-specific CD4+ T cells and generate CD8+ T effector cells able to strongly inhibit IgG2ab production. This result demonstrates the usefulness of CD40 triggering in setting up an immune regulatory mechanism. Furthermore, with regard to the suppression-effector mechanism, we demonstrated that B cell CD40 expression was required for full suppression establishment via the Fas-dependent pathway. Indeed, Igha/a Pfp°/° T cells (using exclusively the Fas pathway) induced full IgG2ab suppression against Ighb/b CD40+/+ B cells, but only partial inhibition of IgG2ab production against Ighb/b CD40°/° B cells. This finding provides the first demonstration of direct involvement of B cell CD40 expression in in vivo negative control of an Ig production.

Central tolerance induction in natural immunoglobulin‐allotype‐specific T cells

While self toleance is induced to IgGb2a in Ighb / b mice, an anti‐IgGb2a T cell activity emerges in their Igha / a congenic counterparts. This activity is revealed by postnatal transfer of Igha / a T splenocytes into Igha / b F1, in which total suppression of IgG2ab expression is established. Here, we sought to determine whether the natural T cell unresponsiveness to IgG2ab in Ighb / b mice involved a central tolerance. Based on the kinetics of postnatal thymic Cγ2ab gene expression in Ighb / b mice, we transplanted thymi from Ighb / b donors of diverse ages into tolerogen‐free Igha / a nu / nu recipients. The state of T cell tolerance or responsiveness to IgG2ab in these reconstituted nu / nu hosts was determined by monitoring the capacity of their splenocytes to induce suppression in Igha / b F1. These experiments demonstrated that: (i) in the Igha / a nu / nu recipients of adult Ighb / b thymi, 33 to 65 % T splenocytes were from nu / nu recipient origin, but these peripheral Igha / a T cells were rendered tolerant to IgG2ab during their differentiation through the adult Ighb / b thymi, (ii) circulating IgG2ab was not a prerequisite for this tolerance induction, (iii) Ighb / b thymic epithelium was unable to induce tolerance to IgG2ab and (iv) IgG2ab‐producing / presenting cells, colonizing the Ighb / b thymi, were certainly responsible of full tolerance induction to IgG2ab.

A study of possible reciprocal influences within the respective allotypy of the polypeptidic chains constituting the immunoglobulin molecule—II: The rabbit b series allotypic specificities

Abstract We did not reveal any difference in the expression of the b series allotypic patterns (carried by the constant region of the κ light chains) either with anti-allotypic sera prepared against IgG or with anti-allotypic sera prepared against light chains when the light chains carrying a given allotypic pattern were respectively associated with allotypically different heavy chains to form an IgG molecule. Very probably, the b series allotypic determinants are relatively far away from the association region of the light and the heavy chains in the IgG molecule. These two kinds of antisera reveal the same set of determinants on IgG and on their isolated light chains, but this set seems to have a different configuration on the isolated light chains and on the same light chain included in the IgG.

Analysis of an antigenic relationship between the b4 and the b6 allotypic patterns of rabbit immunoglobulins

Abstract We described by means of anti-b4 or anti-b6 sera prepared in b5 homozygous rabbits an antigenic relationship between the b4 and the b6 allotypic patterns which are carried mostly by the constant region of the rabbit κ light chains. The allotypic determinants responsible for this cross-reactivity seemed to be mostly conformational ones as they were easily revealed on the intact IgG or their Fab fragments, but were almost undetectable on their separated polypeptidic chains. All the b4 or b6 allotypic subspecificities bore the determinants common to b4 and b6, as well as their exclusive ones.