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J Urbain

Publications and source records attributed to J Urbain.

At least 91 records · Page 5Linked to original sources
PubMed1990

Loss of a major idiotype (CRIA) after repopulation of irradiated mice.

The normal immune response of A/J mice against arsonate coupled to hemocyanin is characterized by a major recurrent cross-reactive Id, the CRIA. This Id is encoded by a single gene segment combination: VHidcr11-DFL16.1e-JH2 for the H chain and Vkidcr-Jk1 for the L chain. In this report, we show that lethal irradiation of A/J mice followed by reconstitution with autologous or syngeneic lymphoid cells results in loss of major CRIA Id expression in the response to arsonate. Different protocols were performed to repopulate the irradiated mice. First, lethally irradiated A/J mice were reconstituted by the transfer of syngeneic bone marrow cells. Second, A/J mice were lethally irradiated while their hind limbs were partially shielded. Third, lethally irradiated A/J mice received a transfer of syngeneic spleen cells. The three groups of mice produce high titers of antiarsonate antibodies completely devoid of CRIA DH-JH related idiotopes expression. Moreover, a lack of affinity maturation is observed in the secondary antiarsonate response of all irradiated and reconstituted mice. A transfer of syngeneic peritoneal cells or a transfer of primed T cells in irradiated and reconstituted A/J mice do not restore in a significant manner either the recurrent CRIA expression or the affinity maturation of the antiarsonate response. Our data suggest that the choice of this Id is not solely dictated by the Igh locus.

Animals↗
PubMed1990

Hypothermia and hypoglycemia induced by anti-CD3 monoclonal antibody in mice: role of tumor necrosis factor.

The possible involvement of tumor necrosis factor-alpha (TNF) in the metabolic disturbances induced by anti-CD3 monoclonal antibodies (mAb) was analyzed in DBA/2 mice injected with 50 micrograms of the anti-murine CD3 mAb 145-2C11. First, we found that 145-2C11 induces a profound hypothermia maximal between 3 h and 6 h after the injection (at 3 h: -3.0 +/- 0.1 degrees C) as well as hypoglycemia (blood glucose levels at 6 h and 24 h: 76 +/- 13 mg/100 ml and 92 +/- 22 mg/100 ml, respectively, p less than 0.001 as compared with control values). These metabolic changes are preceded by the release of TNF into the circulation (peak serum TNF levels at 2 h: 50 +/- 23 pg/ml, p less than 0.01 as compared with controls). The release of TNF induced by 145-2C11 depends on the effect of the mAb on T cells as it is not observed in athymic nude mice while lipopolysaccharide-resistant C3H/HeJ mice also display a significant rise in serum TNF (peak levels at 2 h: 59 +/- 44 pg/ml). Pretreatment of DBA/2 mice with 12 mg of rabbit anti-murine TNF antibodies completely prevents the hypothermia while the hypoglycemia is significantly attenuated. Finally, F(ab')2 fragments of 145-2C11 induce only a transient hypoglycemia (blood glucose levels at 6 h: 109 +/- 14, p less than 0.001 as compared with controls) but neither hypothermia nor significant TNF release. We conclude that TNF is a major mediator of the acute metabolic changes induced by the intact form of 145-2C11.

Animals↗
PubMed1990

A private idiotype can become recurrent through genetic recombination and gene(s) unlinked to the Igh locus governs its expression.

Any immune response is characterized by its idiotypic profile. Two different kinds of idiotype (Id) have been described. Private Id are restricted to a few individuals from a species while recurrent Id appear in a large majority of individuals from the same species immunized with the same antigen. We describe, in this report, an experimental model whereby a private Id can become recurrent through genetic recombination. The immune response of A mice against the hapten arsonate is characterized by a recurrent Id called cross-reactive idiotype A (CRIA). A strongly CRI, called CRIA-like, can be occasionally detected in some BALB/c mice (5% to 10%) immunized with arsonate. Molecular studies show that CRIA and CRIA-like antibodies have highly homologous D segments and identical light chains. By contrast, their VH segments are vastly dissimilar. We have examined the anti-arsonate response of inbred strains of mice whose Igh loci are recombinant between those of A/He and BALB/c. Interestingly, we have observed that the CRIA-like Id which is private in BALB/c becomes recurrent in the AXC-1 strain which harbors the VH genes from BALB/c, the DH and CH genes from A/He. Structural studies demonstrate that highly homologous, VH, VL and D segments are used in BALB/c and AXC-1 mice. The basis for this differential expression of highly similar genes could be linked to the DH locus. However, F1 mice stemming from the cross between AXC-1 and BALB/c do not express the Id. The backcross analysis shows that the non-expression of the Id in F1 mice depends on genes unlinked to the Igh locus.

Animals↗
PubMed1989

Structural characterization of antiidiotypic antibodies. Evidence that Ab2s are derived from the germline differently than Ab1s.

We have found that syngeneic Ab2s in the antiarsonate system are serologically and structurally similar to one another. In contrast, the allogeneic Ab2 response is heterogeneous and derives from a large number of unrelated germline gene segments. The Ab2 response of the BALB/c strain to polyclonal A/J Ars A molecules can probably best be compared with a response to a foreign protein and might have been predicted in a strain that completely lacks the H chain V region gene from which the Ab1 derives. Partial variable region sequences of Ab2s from three other systems in addition to previously reported Ab2 structures indicates that this difference in allogeneic vs. syngeneic Ab2s may be a general phenomena. These data support Jerne's hypothesis of complementary V region genes existing in the germline. However, there is good evidence that these antiidiotypic antibodies are not derived directly from the germline, as somatic processes most likely play an important role in their generation. The D segments of Ab2s in the arsonate system as well as in other systems, are novel in structure and cannot easily be explained by previously described germline D segments. D-D fusion may play a role in the generation of the third hypervariable region in these antibodies.

Amino Acid Sequence↗
PubMed1989

Detection of rotavirus in faecal specimens with a monoclonal antibody enzyme-linked immunosorbent assay: comparison with polyclonal antibody enzyme immuno-assays and a latex agglutination test.

Monoclonal antibodies have been produced against the 81/36F strain of rotavirus. One of them, was chosen as diagnostic reagent: it showed high ELISA reactivity with all the bovine, human and porcine rotavirus strains tested and reacted with VP6, structural protein product known to support the common rotavirus antigen. A sandwich ELISA procedure using the chosen monoclonal as "capture and detecting" antibody was performed to detect rotavirus in faecal samples from experimentally inoculated newborn calves: it always gave a negative response with meconium and a positive response for the stool specimens which rotavirus have been isolated. This assay was compared with Enzygnost and Slidex Rota Kit tests and with a non-commercial sandwich ELISA test using polyclonal antibodies: it showed more sensitivity than the agglutination test and was as sensitive as the other two tests to detect rotavirus in routine diagnostic material. The test evaluated showed no equivocal results.

Animals↗
PubMed1989

In vivo induction of A/J anti-ARS responses with different ranges of affinities: correlation between affinity and CRIA idiotype dominance.

The anti-ARS immune response of A/J mice is characterized by the reproducible and dominant selection of CRIA bearing antibodies. In this report, we have investigated the role of affinity for the antigen in the selection of antibody repertoire during an immune response. A/J anti-ARS responses with different ranges of affinities for arsonate were elicited by the injection of differently arsanylated carrier proteins. The selection of higher affinity A/J anti-ARS responses was shown to be associated with the induction of higher levels of CRIA bearing anti-ARS antibodies. A detailed idiotopic analysis also showed a more precocious selection of the CRIA "canonical combination" in the higher affinity anti-ARS responses. These results strongly suggest an important role for affinity and clonal selection in the dominant expression of the CRIA idiotype in the A/J anti-ARS response.

Animals↗
PubMed1989

CD4-Ia interactions can occur in the absence of T-cell receptor/antigen-Ia recognition.

The T-cell differentiation antigen, CD4, is expressed by major histocompatibility (MHC) class II restricted T lymphocytes. CD4+CD8- T cells use their T-cell receptor to recognize foreign antigens in association with MHC class II products (Ia). The association between CD4 expression and restriction by MHC class II products has led to the hypothesis that CD4 may interact with monomorphic determinants of MHC class II molecules. A large body of experimental evidence suggests that CD4 interaction with MHC class II molecules leads to an increase in the binding avidity of T cell-stimulator cell interactions. A direct test for a functional CD4-MHC class II interaction in T-cell activation requires a separate evaluation of CD4-Ia interactions from T-cell receptor (TcR)-antigen (Ag)/Ia recognition. However, a separate evaluation proves difficult since the T-cell receptor and CD4 may interact with the same MHC class II molecule. In this report, we use a T-cell activation protocol where TcR-Ag/Ia recognition is replaced by TcR complex-anti-CD3 antibody interactions. Therefore, the affinity of the TcR complex for its ligand (the anti-CD3 mAb) is independent from MHC expression on target cells and allows a separate evaluation of the role of accessory molecules in T-cell activation. We have analysed the effects of monoclonal anti-MHC class II antibodies on the activation of a CD4+ T-cell hybridoma in the absence of its TcR restricting MHC class II molecule (I-Ek) but in the presence of unrelated MHC class II molecules (I-Ed, I-Ad). The data obtained indicate a functional interaction between the CD4 molecule and a non-polymorphic region of the MHC class II product in T-cell triggering.

Animals↗
PubMed1989

Self non self discrimination within the immune system: a view from the bridge.

The author reviews the actual concepts on the mechanisms of self-tolerance. He underlines the complexity and the complementarity of the different phenomenons of clonal deletion, clonal anergy and suppression. In addition, he proposes a new theory on the generation of the immune repertoires based on the presentation of self-antigens by particular antigen-presenting cells, the self-presenting cells.

Autoantigens↗
PubMed1988

The effect of prenatal or early postnatal irradiation on the production of anti-arsonate antibodies and cross-reactive idiotypes.

Preliminary studies on the long-term effects of prenatal and early postnatal irradiation on the immune response to arsonate were performed using A/J mice. Pregnant mice were irradiated (0.5 Gy, X-rays) or sham-irradiated on a single occasion during gestation (between day 5 and 18 post-conception). Alternatively, newborn mice received the same treatment between day 2 and 7 after birth. Mice were immunized with keyhole limpet haemocyanin-arsonate (KLH-Ars) in adjuvant from 2 months after birth. The levels of specific antibodies to arsonate (anti-Ars) were measured by radioimmunoassay. In addition, the Ars-related cross-reactive idiotype (CRIA) was measured by the haemagglutination technique. In the primary response the titre of anti-Ars was reduced in animals that had been irradiated between day 12 and 15 of gestation. In the second response, in contrast, they had increased levels of anti-Ars. After immunization with KLH-Ars, high levels of CRIA were observed in all groups. However, in mice irradiated 18-20 days after conception the level of CRIA was often much higher than the level of anti-Ars, indicating that a large proportion of the CRIA-positive molecules were not specific for Ars. Thus, in this particular case, some specificity of the immune response was lost after irradiation. The expression of recurrent idiotypes may be a sensitive indicator of immunological perturbations after irradiation.

Animals↗
PubMed1987

The influence of V kappa gene polymorphism on the induction of silent idiotypes in the arsonate system.

It has been previously shown that it is possible to modify the expressed repertoire of a given individual using idiotypic manipulation. For example, A/J mice respond to arsonate challenge by synthesizing a dominant idiotype, CRIA, whereas BALB/c mice do not. However, after treatment with rabbit polyclonal anti-CRIA antibodies (Ab2 or anti-idiotypic antibodies) and arsonate, BALB/c mice are able to synthesize a CRIA-like idiotype. To determine whether this modification of repertoire is dependent on the immunoglobulin loci (Ig-h, kappa), we have analyzed the anti-arsonate response after anti-idiotypic treatment of three strains of mice (C58, C.C58, AKR), chosen because they are among a small group of strains which express Kappa V regions not seen in other strains. There are also L chains lacking in these strains which are expressed in other mice. The C58 and C.C58 strains share the same Ig-h locus (Ig-ha) with BALB/c mice but C.C58 are congenic mice, that express the kappa loci on a BALB/c genetic background. AKR mice express the Ig-hd haplotype. AKR, C58 and C.C58 do not produce CRIA positive antibodies in response to arsonate; a defect which has been previously mapped to the kappa locus. These three strains of mice (C58, C.C58 and AKR) were treated with rabbit anti-CRIA and boosted with Ars-KLH. The results show that after such treatment, the C.C58 mice were able to express CRIA-like antibodies which are serologically identical to those of BALB/c.

Animals↗
PubMed1987

Monoclonal antibodies against human growth hormone releasing factor, hGRF(1-44)NH2.

Eleven hybridomas secreting monoclonal antibodies (MAb) against amidated human growth hormone releasing factor, hGRF(1-44)NH, have been produced by the cell-fusion technique. Isotyping of the MAbs revealed that ten MAbs belong to the class IgG1 and one to the class IgG3. All light chains belong to the kappa group. The specificity and relative avidity of these MAbs have been determined using an indirect enzyme-linked immunosorbent assay. Nine antibodies exhibit a relatively high avidity for hGRF(1-44)NH2, one is of intermediate avidity and one of low avidity. The epitope specificity of the MAbs, originating from two different mice lines, has been examined in inhibition experiments. All MAbs, except one, display a similar inhibition pattern, suggesting that they recognize the same antigenic determinant. Partial inhibition effects displayed by the last MAb seem to be related to its low affinity for the antigen. Experiments using a shorter, non-amidated form of the antigen, hGRF(1-40)OH, suggest that all MAbs recognize the C-terminal part of hGRF(1-44)NH2.

Animals↗
PubMed1987

Idiotype-anti-idiotype interactions of VHIX-coded anti-progesterone and anti-arsonate antibodies. Comparison of passive haemagglutination and radioimmunoassays.

The reactivity and specificity of polyclonal and monoclonal anti-idiotypic antibodies raised against monoclonal anti-progesterone and anti-arsonate antibodies have been studied by solid phase radioimmunoassay (RIA) with immobilized idiotype and by passive haemagglutination with idiotype-coupled red cells. The sensitivity of the two methods was comparable, though some cross-reactions were only detected by RIA. Passive haemagglutination was found to be especially suitable in screening for monoclonal anti-idiotypes in hybridoma supernatants and ascites, and had advantages over RIA in detection of syngeneic anti-idiotypes. Demonstration of binding site-associated idiotopes was possible by haemagglutination inhibition. RIA and haemagglutination were used to investigate the idiotypic relationships between BALB/c antiprogesterone and anti-arsonate monoclonal antibodies which share heavy chains encoded by VHIX variable region genes.

Amino Acid Sequence↗
PubMed1986

Molecular mapping of idiotopes of anti-arsonate antibodies.

As part of understanding molecular function in structural terms, we have been attempting to map the idiotypic topography of specific anti-arsonate (Ars) antibodies. A panel of anti-Ars hybridomas of which the complete primary sequences are known were used. These molecules show a varied reactivity profile with a panel of monoclonal anti-idiotypic antibodies. By judicious chain recombination experiments and chemical modifications that altered this reactivity profile, we were able to identify particular amino acid residues or discreet regions of anti-Ars antibodies as having crucial roles in the expression of idiotypic determinants. Idiotopes were mapped to the heavy chain second hypervariable region and D segment, and to the light chain first and third hypervariable regions.

Amino Acid Sequence↗
PubMed1986

Anti-idiotypic treatment of BALB/c mice induces CRIa-bearing suppressor cells with altered Igh-restricted function.

The ABA-specific antibody response of A/J mice (Igh Ie) is dominated by the CRIa idiotype. In contrast, BALB/c mice (Igh Ia) do not produce CRIa-bearing anti-ABA antibodies after antigenic challenge. We have shown previously that treatment with rabbit anti-CRIa (R-anti-CRIa) induces the expression of "CRIa-like" anti-arsonate antibodies in BALB/c mice. In the present report, we demonstrate that R-anti-CRIa treatment enables BALB/c mice to respond to A/J ABA-specific first-order suppressor molecules (TsF1). Manipulated BALB/c also produced CRIa bearing ABA-specific immune response. Thus, R-anti-CRIa treatment induces a change in the characteristic Igh restriction pattern typically seen in this system. These data suggest that Igh restriction in the ABA-specific T suppressor cell pathway is the result of CRIa+ dominance in the T suppressor cell response of A/J mice. The effectiveness of idiotypic manipulation in inducing the expression of a given idiotype at both the B cell and T suppressor cell levels is discussed.

Animals↗
PubMed1986

Study of idiotopic suppression induced by anti-cross-reactive idiotype monoclonal antibody in the anti-p-azophenylarsonate antibody response.

A/J mice immunized with p-azophenylarsonate coupled to keyhole limpet hemocyanin produce antibodies expressing a cross-reactive idiotype (CRIA). The pretreatment of A/J mice with anti-idiotypic polyclonal or monoclonal antibody directed against the major cross-reactive idiotype (CRIA) borne by p-azophenylarsonate-specific antibody can lead to idiotypic suppression. In this study, we investigate this idiotypic suppression by using four mAb2 (E4, H8, E3, 2D3) recognizing distinct idiotopes whose expression is related to the presence of particular gene segments of the heavy chain V region. 2D3 expression has been related to the presence of some amino acid in the CDR2 region of the VH gene segment derived from the germ line VH IdCR11. So far, the latter is the only germ-line gene coding for CRIA+ antibody that has been identified in the A/J genome. E4 and H8 expression has been related to the use of a particular D segment, whereas E3 expression has been attributed to certain combinations of D and JH segments. Therefore, we might expect independent regulation of the expression of those various idiotopes in relation to the mechanism of gene recombination. Indeed, we observed that 2D3-suppressed A/J mice still produce the three other idiotopes, suggesting the recombination of those particular D and J segments with a different VH gene. Such a gene has been identified in the genome of BALB/c mice. A/J mice pretreated with one of the other three mAb2 are generally cosuppressed for the expression of E4, H8, and E3, but they still produce 2D3+ antibody. In this case, the IdCR11 VH germ-line gene is most probably recombined with different D and J segments. Molecular evidence for the existence of such molecules has also been presented in the literature. So our serologic data on idiotopic suppression in the arsonate system can be compared with recent data provided by molecular genetics.

Amino Acid Sequence↗
PubMed1986

Idiotypic games within the immune network.

In this paper, we have considered the problem of selection of available repertoires. With Ab2 as immunogens, we have used the idiotypic cascade to explore potential repertoires. Our results suggest that potential idiotypic repertoires are more or less the same within a species or between different species. A given idiotype "à la Oudin" can become a recurrent one within the same outbred species or within different species. Similarly, an intrastrain crossreactive idiotype can be induced in other strains, even though there is a genetic disparity between these strains. The structural basis of this phenomenon has been explored. We next examined results showing the loss and gain of recurrent idiotypes without any intentional idiotypic manipulation. A recurrent idiotype can be lost in a syngeneic transfer and a private one can become recurrent by changing the genetic background. The change of available idiotypic repertoires at the B cell level has profound influences on the idiotypic repertoires of suppressor T cells. All these results imply that idiotypic games are played by the immune system itself, a strong suggestion that the immune system is a functional idiotypic network.

Animals↗