Methods
In this paper we review the existing evidence that peritoneally derived B-1 cells may contribute significantly to the generation of IgA-secreting plasma cells in the murine intestinal lamina propria. The evidence is based upon a variety of experimental approaches performed in our laboratory and others and include (i) transfer studies of (sorted) B-1 cells into B-cell-depleted mice either experimentally...
Metabolic changes associated with B-cell activation can be studied in B-1 cells through the same biochemical techniques used for analysis of B-2 cells. However, difficulty may be encountered in obtaining sufficiently large numbers of purified cells. Several negative selection techniques have been combined to isolate B-1 cells for signaling studies. Purified B-1 cells have been found to differ from...
Interleukin-5 (IL-5) is a cytokine that stimulates proliferation and differentiation of B cells including CD5-positive B (B-1) cells and eosinophils. IL-5 signals can be transduced through IL-5 receptor (IL-5R) that is composed of α and βc chains. The IL-5Rα specifically binds IL-5 and the βc chain forms the high-affinity receptor with IL-5Rα and is indispensable for IL-5 signal transduction, although...
CTLA-4 and CD28 are homologous T-cell surface receptors that associate with the B7-related counter receptors, B7-1 (CD80) and B7-2 (CD86), expressed on antigen-presenting cells. This association establishes the molecular basis for an important T-cell costimulatory pathway, the primary function of which is to induce T-cell cytokine production and proliferation following exposure to antigen. CTLA4Ig...
The variable regions of the T-cell receptor for antigen (TCR) and antibodies serve as recognition elements, enabling T and B cells to bind antigen with high specificity. Nevertheless, the complex recognition requirements of T cells, which respond to antigen only in the context of a self MHC molecule, do not permit the generation of antigen-specific lymphocytes, which could serve as universal effector...
Advances in molecular biology have enabled the manipulation of immunoglobulin molecules to produce chimeric antibodies with novel properties or improved effector functions. Such antibodies are produced in mammalian expression systems using specially designed vectors and selectable markers. Three principal applications for such recombinant antibodies are described. Antibodies with clinically important...
Much work has been directed at the development of reagents that would combine the specificity of antibodies with potent and readily manipulated cytotoxic effector functions. In this review, we describe immunotoxins, molecules that contain an antibody-derived antigen binding region (Fv) coupled to a bacterial toxin, most commonly Diphtheria toxin orPseudomonasexotoxin. Second-generation immunotoxins...
Phage display of antibody fragments provides a convenient format for directed molecular evolution of this biologically important protein architecture. Current understanding of the natural evolution of antibodiesin vivohas allowed their synthesis and selectionin vitro.Synthetic antibodies have been demonstrated to utilize the same mechanisms of molecular recognition as those used by natural antibodies...
The binding of IgE antibodies to their specific receptors on mast cells is a crucial step in the allergic response and can serve as a paradigm for the study of receptor–ligand interactions. Intense efforts have been made to identify amino acid sequences and structural motifs on the IgE molecule that may be involved in the binding to the Fcϵ receptor. Studies using short IgE peptides or fragments are...
Immunoadhesins are chimeric, antibody-like molecules that combine the functional domain of a binding protein, usually a receptor, ligand, or cell-adhesion molecule, with immunoglobulin constant domains, usually including the hinge and Fc regions. Immunoadhesins have many applications as research tools, for example, in studies of receptor–ligand interactions. In addition, human immunoadhesins have...
Chimeric mAbs may be substituted for their murine equivalents when used in therapy to minimize the immune response directed against species-specific antigenic determinants. Open-labeled and placebo-controlled trials of the mouse/human chimeric CD4 mAb, cM-T412, were conducted in patients with rheumatoid arthritis refractory to treatment with disease-modifying anti-rheumatic drugs. The treatment was...
The strategy for tumor suppressor gene therapy for cancer is to suppress the malignant phenotype of tumor cells by replacing the inactivated gene with a normal (wild-type) one to restore control of cell growth and differentiation. To effectively carry out this strategy, the therapeutic genes must be delivered efficiently and expressed at an adequate level in the tumor. Adenoviral vectors have rapidly...
Foreign and self endogenous proteins can be processed and presented as peptides bound to class I and II MHC to CD8 or CD4-positive T cells. In the case of mutant tumor suppressor proteins, proteosomal processing of the mutant protein could occur either in the tumor cell or in an antigen-presenting cell to generate a variety of peptides that can be transported into the endoplasmic reticulum and loaded...
Mutational inactivation of the p53 gene product is one of the most frequent genetic alterations in human cancers. Depending on the promoter or gene context, the p53 protein can function as a transcriptional activator or repressor. During the late 1970s and first half of the 1980s, p53 was believed to encode a protein with oncogenic potential. However, later work established a tumor suppressor role...
Techniques in somatic cell genetics have proven to be very important in the elucidation of genetic mechanisms in cancer and, in particular, the functional definition of tumor suppressor genes. Genetic complementation studies using microcell fusion have allowed the identification of specific chromosomes and particular chromosome regions that contain functional tumor suppressor genes for a variety of...
Defects in vital genes occur in a high percentage of human diseases, including cancer. Defects could be due to the accumulation of mutations in the genes leading to the production of faulty proteins. Although the biological significance of such mutant proteins still remains in question, recent experiments have demonstrated that genes overproducing faulty proteins are often associated with tumor cell...
Identification and analysis of tumor suppressor genes has relied chiefly upon studies of human sporadic tumors and of tumors harvested from familial cancer syndrome patients. One methodology that is proving to be extremely useful both in analyzing the function of these genes and in identifying new tumor suppressor genes involves the creation of transgenic mice that contain targeted mutations that...
Several proteins that function as transcription factors play important roles in tumor suppression because they function as modulators of gene expression. p53, for example, activates the transcription of genes that are involved in growth suppression or apoptosis. The stability of p53 is greatly increased upon DNA damage, indicating its role in these processes. In contrast to p53, WT1 appears to function...