Le développement d'anticorps thérapeutiques a suscité beaucoup d'intérêt au cours des dernières décennies. Plus de 30 d'entre eux ont été approuvés et sont utilisés pour traiter des patients atteints de cancer. Les récepteurs agonistes de TRAIL (DR4 ou DR5) sont surexprimés par les cellules tumorales et capables de déclencher leur mort. Ils représentent donc des cibles idéales. Malgré des résultats encourageants, la plupart des essais cliniques basés sur des anticorps monoclonaux ciblants DR4 ou DR5 ont été interrompus. Cependant, les connaissances actuelles ouvrent des perspectives thérapeutiques de choix pour l'utilisation de tels anticorps en oncologie. Afin de développer de nouveaux anticorps anti-DR4 et anti-DR5 reconnaissant sélectivement les protéines natives d’intérêt, et doués de propriétés antitumorales, nous avons opté pour une approche d'immunisation génétique basée sur des injections hydrodynamiques d'ADN complémentaire. Cette approche nous a permis d'obtenir des réponses humorales significatives, et après fusions des rates correspondantes, de générer 21 anticorps monoclonaux capables de reconnaître spécifiquement et avec une très grande affinité les récepteurs DR4 ou DR5, sous leurs formes natives. Parmi ces anticorps monoclonaux, deux sont doués de propriétés pro-apoptotiques, et quatre sont capables d'accroitre le potentiel pro-apoptotique du ligand TRAIL. Les propriétés antitumorales de l'anticorps anti-DR4 le plus puissant, l’AcM-C#16, ont également été validées in-vivo dans des modèles de xénogreffes.L'ensemble de ce travail démontre, et ce pour la première fois, que la méthode d'immunisation ADN par injection hydrodynamique peut être utilisée pour générer des anticorps monoclonaux thérapeutiques efficaces ciblant des récepteurs de la superfamille du TNF. Au-delà du système TRAIL, cette approche d'immunisation, peu exploitée, pourrait ouvrir de nouvelles perspectives thérapeutiques en l'adaptant à de nouvelles cibles. / Development of therapeutic antibodies has attracted many interests in recent decades. More than 30 of them have been approved and are used to treat cancer patients. TRAIL agonist receptors (DR4 or DR5) are overexpressed by the tumour cells and are able to trigger their death. Therefore, they represent ideal targets. Despite encouraging results, most clinical trials based on monoclonal antibodies targeting DR4 or DR5 have been discontinued. However, current knowledge opens therapeutic perspectives of choice for the use of such antibodies in oncology. In order to develop new anti-DR4 and anti-DR5 antibodies recognizing selectively the native form of the proteins of interest, and endowed with antitumor properties, we have chosen to perform a genetic immunization approach based on hydrodynamic injections of complementary DNA. This approach allowed us to obtain significant humoral responses, and after fusions of the corresponding spleens, to generate 21 monoclonal antibodies capable of recognizing specifically and with very high affinity DR4 or DR5 receptors, in their native forms. Of these monoclonal antibodies, two are display pro-apoptotic properties, and four are capable of enhancing TRAIL pro-apoptotic potential. The antitumor properties of the most potent anti-DR4 antibody, mAb-C16, have also been validated using in-vivo xenografts models.Altogether this work demonstrates, for the first time, that the DNA immunization hydrodynamic injection method can be used to generate therapeutically effective monoclonal antibodies targeting TNF superfamily receptors. Beyond the TRAIL system, this immunization approach, scarcely exploited, could open new therapeutic perspectives by adapting it to new targets.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Genetic as well as environmental factors are believed to be of importance in the etiology of rheumatoid arthritis (RA). There are a number of previous studies of genetic markers in RA, but so far no genetic linkage and only a few associations have been found. Of the associations only one (with the HLA antigen DR4) appears to be well documented. In most previous association studies the patients have not been divided according to sex and family history of RA. In this investigation the HLA antigens A, B and DR and five serum protein systems (Bf, C3, Pi, Hp and Tf) were studied in patients with erosive rheumatoid arthritis (RA), from northern Sweden. Special attention was paid to variations in the strength of associations accord­ing to sex and family history of polyarthritis. The following results were found:  The frequency of the HLA antigen B27 was significantly increased in the North-Swedish population (16.6%) and among patients with a family history of polyarthritis (42.6%). In agree­ment with previous investigations a significantly increased frequency of the DR4 antigen was found in the RA patients.  In the properdin factor B (Bf) system the S phenotype was found to be significantly in­creased in male patients and in patients with a family history of polyarthritis, more severe form of RA and high titres of rheumatoid factor.  No significant differences with respect to phenotype or gene frequencies were found in the C3 complement system. Thus, the association between RA and C3 found in previous investiga­tions was not confirmed.  A significant increase of rare alpha-1-antitrypsin (Pi) types (MS, MZ, MF and SZ) was found among RA patients. However, the increase concerned mainly Z heterozygotes and was more strongly pronounced among male patients.  In the haptoglobin system a significant increase of the Hp^ gene and the Hp2-2 type was found among patients with a family history of polyarthritis, more pronounced among males.  A significant increase of the transferrin gene and of the 2 type was found among male RA patients, more pronounced among patients with a family history of polyarthritis. In 6 out of 8 gene loci studied significant associations were found, which is in agreement with a multifactorial etiology of RA. The results were largely in agreement with the hypothesis that associations would be expected to be stronger in males and in patients with a family history of polyarthritis. A notable finding was the high frequency of first degree relatives (around 40%) with symmetric peripheral polyarthritis of which more than 70% had a diagnosis of RA verified by hospital records. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1985, härtill 6 uppsatser.</p> / digitalisering@umu