The human anti-bullous pemphigoid monoclonal autoantibody P22 is encoded by genes of the IGHV4 and IGLV4 families.

We identified, cloned, and biochemically characterized the full-length cDNAs encoding the heavy and light chains of a human monoclonal antibody (mAb) from the Epstein-Barr virus (EBV)-cell line P22. The cell line P22, which originated from a patient with bullous pemphigoid (an autoimmune disease causing skin blistering) expressed immunoglobulin-G (IgG) with a lambda light chain. Although the variable heavy (IGHV) chain gene family could not be assigned by IGHV repertoire analysis, the determination of its nucleotide sequence demonstrated that the heavy chain of P22 belonged to the IGHV4 family. The limited IGHV4 gene usage by memory IgG, IGA and IgE-expressing cells supports the notion of the autoreactivity-associated IGHV4 genes and stresses the strong selection pressure within germinal centres towards IGHV4 family. Alignment of P22 IGHV4 cDNA sequence to germline sequences from gene databases, revealed a remarkable divergence, suggesting that the heavy chain of the P22 mAb encodes a distinct IGHV4 gene. The variable light chain (IGLV) encodes a IGLV4 gene and is 98% similar to a previously reported IGLV gene. Furthermore, fluorescent staining with the recombinant mAb showed the same reactivity to that of the native antibody. The data reported herein, (a) reveal an autoantibody encoding a distinct IGHV4 gene, (b) confirm the notion that autoantibodies preferentially use IGHV4 genes, and (c) hypothesize that somatic hypermutation within GC may be a mechanism by which autoreactive B lymphocytes escape negative selection.

The efficacy and acceptability of amineptine versus fluoxetine in major depression.

The temporal dimension, particularly anticipation, appears to be a very important component in the understanding of depressed patients. In a 90-day multicentre study, the efficacy and acceptability of amineptine and fluoxetine were compared in 169 patients with major depression. Comparison of the two antidepressants was based on double-blind methods, after random allocation of the treatments between two parallel groups. The two drugs did not differ over the whole course of the study, but the improvement in scores on day 4 was globally more marked in the amineptine than the fluoxetine group. Intragroup analysis showed that amineptine was significantly superior to fluoxetine on the retardation pole of the mood, anxiety, retardation, danger scale. The positive effect of amineptine on anticipation may enable the depressed patient to make plans for the future. Anticipation may be a key dimension to be more precisely explored in specific psychopharmacological protocols with antidepressants.

Identification of human IgG autoantibodies specific for IL-10.

Since autoantibodies to IL-1alpha, interferon-alpha (IFN-alpha) and IL-6 have been described, this study concentrated on the search for autoantibodies to hIL-10 using an assay based on the precipitation of 125I-hIL-10 autoantibody complexes using Protein G-Sepharose. Among 1860 tested sera, only seven were found to specifically precipitate IL-10, thus indicating the rare occurrence of such autoantibodies. Four of those seven anti-IL-10 autoantibody sera were specific for hIL-10, two recognized both human and viral IL-10, while the last one recognized human, viral and murine IL-10, thus suggesting the existence of at least three different epitopic specificities. The purification of anti-IL-10 autoantibody from one serum demonstrated the existence of a single (IgG1, lambda) autoantibody that neutralized IL-10 biological activity. Thus, autoantibodies to IL-10 may represent natural antagonists to IL-10.

Major histocompatibility complex class I-restricted CD8+ T cells and class II-restricted CD4+ T cells, respectively, mediate and regulate contact sensitivity to dinitrofluorobenzene.

Contact sensitivity (CS) is a form of delayed-type hypersensitivity to haptens applied epicutaneously and is thought to be mediated, like classical delayed-type hypersensitivity responses, by CD4+ T helper-1 cells. The aim of this study was to identify the effector T cells involved in CS. We studied CS to the strongly sensitizing hapten dinitrofluorobenzene (DNFB) in mice rendered deficient by homologous recombination in either major histocompatibility complex (MHC) class I, MHC class II, or both, and which exhibited deficiencies in, respectively, CD8+, CD4+, or both, T cells. MHC class I single-deficient and MHC class I/class II double-deficient mice, both of which have a drastic reduction in the number of CD8+ T cells, were unable to mount a CS response to DNFB. In contrast, both MHC class II-deficient mice and normal mice treated with an anti-CD4 monoclonal antibody (mAb) developed exaggerated and persistent responses relative to heterozygous control littermates. Furthermore, anti-CD8 mAb depletion of class II-deficient mice totally abolished their ability to mount an inflammatory response to DNFB. Removal of residual CD4+ T cells in class II-deficient mice by anti-CD4 mAb treatment did not diminish the intensity of CS. These data clearly demonstrate that class I-restricted CD8+ T cells are sufficient for the induction of CS to DNFB, and further support the idea that MHC class II-restricted CD4+ T cells down-regulate this inflammatory response.

Oral tolerance to haptens: intestinal epithelial cells from 2,4-dinitrochlorobenzene-fed mice inhibit hapten-specific T cell activation in vitro.

The mechanisms underlying the induction of immunological tolerance after feeding soluble exogenous antigens, including proteins and haptens, are still unclear. Using a model of oral tolerance to the contact-sensitizing hapten 2,4-dinitrochlorobenzene (DNCB), we have compared the ability-of intestinal epithelial cells and of Peyer's patch APC to present DNCB in vitro or ex vivo after oral feeding, to specific peripheral lymph node T cells from DNCB-sensitized mice. In contrast to Peyer's patch APC, which induce efficient hapten-specific T cell activation upon exposure to the hapten either in vitro or in vivo, mature MHC class-II-positive intestinal epithelial cells were unable to induce T cell activation in either case. Interestingly, enterocytes from DNCB-fed mice exerted a dramatic inhibitory effect on the proliferative response of hapten-primed T cells in response to dinitrobenzene sulfonate presented by syngeneic spleen cells. This inhibitory effect, which was also observed with supernatant of intestinal epithelial cells from DNCB-fed mice, could be reversed by neutralizing anti-transforming growth factor (TGF)-beta antibodies. In addition, pre-incubation of hapten-sensitized T cells with enterocytes from DNCB-fed mice induced T cell anergy, which could be reversed by exogenous interleukin-2 or interleukin-4. These data demonstrate that intestinal epithelial cells activated in vivo by oral administration of DNCB are able to block proliferation of activated T cells through secretion of immunosuppressive cytokines such as TGF-beta. It is proposed that intestinal epithelial cells may play a significant role in oral tolerance by limiting T cell-mediated hypersensitivity responses.

[Study of epitopic sites of the major bullous pemphigoid antigen (BPAg1)]. / Etude des sites épitopiques de l'antigène majeur de la pemphigoïde bulleuse (BPAg1).

Bullous pemphigoid is an acquired blistering skin disease associated with the production of IgG autoantibodies to 230 kDa BP Ag (BPAg1) and to 180 kDa BP Ag (BPAg2). The aim of our work was to better characterize the epitopes of BPAg1. For this, we firstly generated a bullous pemphigoid recombinant protein of 55 kDa Mr (rBP55) from a cDNA sequence encoding for the carboxyterminal region of the 230 kDa BP antigen. Ninety-two percent of sera from patients with autoantibodies to the 230 kDa polypeptide recognized the rBP 55 protein. These results confirm that this 555 aminoacid segment corresponding to rBP 55 contains major epitopes. In order to study the epitopes of the amino-terminal portion of the BPAg1 antigen, we generated immortalized B cell lines secreting human monoclonal antibodies to BPAg1 from two patients whose sera reacted with native BPAg1 but not with the recombinant rBP55 carboxy-terminal peptide. Blocking immunofluorescence experiments and phylogenetic studies showed that these human monoclonal antibodies recognize different epitopes of BPAg1. According to these studies, we can conclude on the wide variety of epitopes recognized by BPAg1 autoantibodies.

Human monoclonal autoantibodies specific for the bullous pemphigoid antigen 1 (BPAg 1).

Bullous pemphigoid (BP) is an acquired blistering skin disease associated with the production of IgG autoantibodies to the 230-kDa BP Ag (BPAg1). To better characterize the epitopes of BPAg1, we generated immortalized B cell lines secreting human mAbs (HumAbs) to BPAg1 from two BP patients whose sera reacted with native BPAg1 but not with a recombinant BP55 carboxyl-terminal peptide. Ab-producing B cell lines were established by EBV infection of CD40-activated PBMCs. Three independent clonal lines were obtained that secreted IgG HumAbs, including one IgG1 kappa (BP3) and two distinct IgG4 kappa (BP1 and BP2). These three HumAbs immunoprecipitated BPAg1. Blocking immunofluorescence experiments and phylogenetic studies showed that these Abs recognize different epitopes of BPAg1. This analysis with HumAbs further extends the serologic demonstration of the wide variety of epitopes recognized by BPAg1 autoantibodies which contrasts with the limited number of epitopes recognized by thyroid peroxidase monoclonal autoantibodies.

[Comparative study of the efficacy and acceptability of amineptine and fluoxetine in patients with major depression]. / Etude comparative de l'efficacité et de l'acceptabilité de l'amineptine et de la fluoxétine chez des patients dépressifs majeurs.

We compare two anti-depressant drugs, amineptine and fluoxetine, in a multicentric study. Amineptine is a dopamine reuptake inhibitor, and fluoxetine a serotonin reuptake inhibitor. Eighteen french centers participate in the study. One hundred and sixty nine outpatients were randomly assigned to either 200 mg of amineptine or 20 mg of fluoxetine during 90 days. They fulfilled the DSM III-R criteria of major depressive disorder. They were aged from 18 to 70. Minor tranquilizers were allowed during the study. The patients were evaluated at D0, D7, D21, D42 and D90. If possible, an additional evaluation was made at D4. Clinical evaluations included Clinical Global Investigation (CGI), Montgomery and Asberg Depressive Rating Scale (MADRS), HARD scale, Widlocher Retardation rating scale and Hopkins Symptom Check-list (HSCL). Somatic concerns were recorded at each visit. Among the 169 patients included in the study, only 141 ended it at D90. The two drugs had good antidepressive efficacy which was noticed as soon as D7 up to D90. If we compare the antidepressant activity, no statistical differences could be observed between the two drugs using different scales. The percentage of patients with an improvement of at least 50% of the global score at MADRS was 8.3% at D7; 41% at D21, 69.2% at D42 and 83.2% at D90 for the amineptine group. For the fluoxetine group, these percentages were, 7.7%; 37.8%; 78.9%; 82.1%. No statistical differences could be noticed between the two groups, and at any time of the study. We have tried to look for a rapid antidepressive action by a clinical evaluation at D4.(ABSTRACT TRUNCATED AT 250 WORDS)