Current Concepts in the Treatment of Autoimmune Diseases with Monoclonal Antibodies

Development and Characterization of a Novel Single-Chain Antibody Against B-Cell Activating Factor

As a member of the tumor necrosis factor (TNF) superfamily, the B-cell activating factor (BAFF) plays a crucial role in B-cell survival and differentiation. Overexpression of this protein has been closely linked to autoimmune disorders and some B-cell malignancies. Using monoclonal antibodies (mAbs) against the BAFF soluble domain appears to be a complementary treatment for some of these diseases. This study aimed to produce and develop a specific Nanobody (Nb), a variable camelid antibody domain, against the soluble domain of BAFF protein. After camel immunization with recombinant protein and preparing cDNA from total RNAs separated from camel lymphocytes, an Nb library was developed. Individual colonies capable of binding selectively to rBAFF were obtained by periplasmic-ELISA, sequenced, and expressed in a bacterial expression system. The specificity and affinity of selected Nb were determined and its target identification and functionality were evaluated using flow cytometry.

Interferon gamma, IL2, IL4, IL10 and TNFalpha secretions in multiple sclerosis patients treated with an anti-CD4 monoclonal antibody

In order to better understand the mechanisms of action of a monoclonal anti-CD4/BF5 antibody(mAb), cytokine secretions were studied in 14 multiple sclerosis (MS) patients treated in a phase 1 trial. Secretion patterns of IFNgamma, IL2, IL4, IL10 and TNFalpha by peripheral blood mononuclear cells were studied before (DO) and after (D30) the treatment. We decided to undertake this study because in a previous one we observed no variations in serum levels of TNFalpha, IFNgamma, IL1, IL6. Results showed significant reductions in IFNgamma, IL2 and TNFalpha secretions after treatment. The anti-CD4 mAb seemed to act on both Th1- and Th2-cells but with preferential action on Th1-cells. Results on Th2-cells were less obvious even though a significant decrease in IL10 was observed. There was no correlation between any of the immunological markers studied and disease activity. This study demonstrates that pharmacological modifications of the CD4 receptor can induce variations in several cytokine secretion levels. It also stresses the role played by Th1- and Th2-cells in the etiopathogenesis of MS.

Partial restoration of hair growth in the DEBR model for Alopecia areata after in vivo depletion of CD4+ T cells

Alopecia areata (AA) is widely believed to be an autoimmune disease. Hair loss is associated with a peri- and intrafollicular inflammatory infiltrate of anagen hair follicles primarily composed of CD4 + and CD8 + cells. A previous investigation involved in vivo depletion of CD8 + cells in the DEBR rat model to examine the cells' potential pathogenic activity in AA. The rat model is used here in a comparable study of CD4 + cell pathogenic activity. Eight AA affected DEBR rats were given intraperitoneal injections of a CD4 + cell depleting OX-35/OX-38 monoclonal antibody (MoAb) cocktail over a 15-day therapy course. A further eight AA-affected rats comprised a control group and were injected with equivalent volumes of an irrelevant MoAb, OX-21. Changes in both CD4 + and CD8 + peripheral blood cell populations were analysed by flow cytometry, and macrophotography was used to record any changes in hair growth. Of the eight CD4 + cell-depleted rats six responded with hair growth. The rats revealed significant hair growth within 23 days of treatment initiation. With rapid replacement of the CD4 + cell population the newly generated pelage hair was eventually lost. Two control rats also showed limited hair growth within the 112-day study period. In vivo depletion of CD4 + cells partially restores hair growth in AA affected rats. The response suggests that CD4 + cells may be actively involved in the pathogenesis of AA. Further research may elucidate whether CD4 + cells have a direct effect on hair follicles or exert their influence through their classic T helper cell supporting role for CD8 + cells.