Antibodies2014, 3(1), 130-152; doi:10.3390/antib3010130 - published online 20 February 2014 Show/Hide Abstract
Abstract: Alloimmunization is an undesirable iatrogenic effect of transfusion and transplantation. In fact, recipients can be considered as responders or not responders, in a continuum from tolerance, including organ transplantation and transfusion, to polyimmunized and refractory patients. New models and large studies have enabled a better understanding of the mechanisms that induce specific alloantibody (alloAb) generation. Here, we focus on risk factors of alloimmunization. We review the alloantibody characteristics, summarize the different leukocytes involved in their induction, and suggest some hypotheses.
Antibodies2014, 3(1), 116-129; doi:10.3390/antib3010116 - published online 19 February 2014 Show/Hide Abstract
Abstract: B lymphocyte receptors are generated randomly during the bone marrow developmental phase of B cells. Hence, the B cell repertoire consists of both self and foreign antigen specificities necessitating specific tolerance mechanisms to eliminate self-reactive B cells. This review summarizes the major mechanisms of B cell tolerance, which include clonal deletion, anergy and receptor editing. In the bone marrow presentation of antigen in membrane bound form is more effective than soluble form and the role of dendritic cells in this process is discussed. Toll like receptor derived signals affect activation of B cells by certain ligands such as nucleic acids and have been shown to play crucial roles in the development of autoimmunity in several animal models. In the periphery availability of BAFF, a B cell survival factor plays a critical role in the survival of self-reactive B cells. Antibodies against BAFF have been found to be effective therapeutic agents in lupus like autoimmune diseases. Recent developments are targeting anergy to control the growth of chronic lymphocytic leukemia cells.
Antibodies2014, 3(1), 92-115; doi:10.3390/antib3010092 - published online 19 February 2014 Show/Hide Abstract
Abstract: Targeted therapies for the treatment of cancer, but also inflammation and autoimmune diseases will reduce major side effects accompanied with conventional treatment modalities. The immunotoxin concept uses bacterial or plant toxins, coupled to antibodies or natural ligands targeting cancer cells. Initially, immunotoxins suffered from drawbacks like nonspecific cytotoxicity. Even the third generation of immunotoxins comprised of truncated antibodies and modified effector molecules experienced clinical set-backs due to immune responses. Long-term treatment of cancer and non-life-threatening chronic inflammatory diseases requires their complete ‘humanization’. This lead to evaluating human cytolytic fusion proteins (hCFPs), based on human apoptosis-inducing proteins. Lacking an endogenous translocation domain dramatically reduces the cell-death inducing capacity of such proteins. Here, we report on optimizing hCFPs, based on the anti-CD64 single chain variable fragment H22(scFv), specifically eliminating CD64+ macrophages and malignant progenitor cells. We replaced the bacterial toxin in H22(scFv)-ETA' with the pro-apoptotic human granzyme B or angiogenin. Translocation was promoted by a sophisticated adapter containing a membrane transfer peptide (MTD) flanked by endosomal and cytosolic cleavable peptides, thus achieving in vitro cytotoxic activity comparable to bacterial immunotoxins. We demonstrate for the first time that optimized hCFPs, based on granzyme B or angiogenin, can compete with classical ETA-based immunotoxins.
Antibodies2014, 3(1), 56-91; doi:10.3390/antib3010056 - published online 22 January 2014 Show/Hide Abstract
Abstract: The variety of chemically diverse pharmacologically-active compounds administered to patients is large and seemingly forever growing, and, with every new drug released and administered, there is always the potential of an allergic reaction. The most commonly occurring allergic responses to drugs are the type I, or immediate hypersensitivity reactions mediated by IgE antibodies. These reactions may affect a single organ, such as the nasopharynx (allergic rhinitis), eyes (conjunctivitis), mucosa of mouth/throat/tongue (angioedema), bronchopulmonary tissue (asthma), gastrointestinal tract (gastroenteritis) and skin (urticaria, eczema), or multiple organs (anaphylaxis), causing symptoms ranging from minor itching and inflammation to death. It seems that almost every drug is capable of causing an immediate reaction and it is unusual to find a drug that has not provoked an anaphylactic response in at least one patient. These facts alone indicate the extraordinary breadth of recognition of IgE antibodies for drugs ranging from relatively simple structures, for example, aspirin, to complex molecules, such as the macrolide antibiotics composed of a large macrocyclic ring with attached deoxy sugars. This wide recognition profile is borne out at the molecular level by results of quantitative immunochemical studies where hapten inhibition investigations have identified structural determinants complementary to IgE antibodies in the sera of allergic subjects. Allergenic determinants have been identified on a variety of drugs including neuromuscular blockers, penicillins, cephalosporins, opioids, thiopentone, sulfonamides, trimethoprim, quinolones, chlorhexidine and the non-steroidal anti-inflammatory drug aspirin. It is already clear that IgE can distinguish fine structural differences on a wide variety of molecules, determinants may be at least as small as an amino group or encompass the whole molecule, and individual drugs may demonstrate allergenic heterogeneity.
Antibodies2014, 3(1), 37-55; doi:10.3390/antib3010037 - published online 16 January 2014 Show/Hide Abstract
Abstract: ADP-ribosylation is an essential post-translational modification, mediated by a family of proteins named poly-ADP-ribose polymerases/Diphtheria toxin-like ADP-ribosyltransferases (PARPs/ARTDs), that functions to assist in cellular homeostasis through an array of mechanisms. Although the function of PARP1/ARTD1-mediated poly-ADP-ribosylation (PARylation) in response to environmental genotoxic stressors has been extensively studied, its role in the regulation and maintenance of cellular events under times of programmed DNA damage and repair remains to be elucidated. In the case of B cell maturation and differentiation, processes such as V(D)J recombination, somatic hypermutation, and class switch recombination, require the induction of DNA strand breaks for the generation of a varied immunoglobulin repertoire and, thus, serve as a model system to explore the function of PARylation in immunological processes. In this review, we summarize the current understanding of ADP-ribosylation and the PARPs/ARTDs family proteins, in particular PARP1/ARTD1-conferred PARylation, in B cells. Following an overview of PARylation in cellular responses to environmental and spontaneous DNA damage, we discuss the emerging function of PARP1/ARTD1 and PARylation in DNA damage-induced nuclear factor kappaB (NF-κB) signaling and B cell maturation and differentiation. Finally, we conclude by underlining further efforts that are needed to understand how the PARPs/ARTDs family proteins and ADP-ribosylation control the development and function of B cells.