Advances in molecular biology and immunology have renewed interest in the development of vaccines for the treatment or prevention of cancer. Research over the past 10 years has focused on the identification of suitable tumour antigens to use as targets for a variety of vaccine strategies. Carcinoembryonic antigen (CEA) was one of the first tumour antigens described, and is commonly expressed by a wide range of adenocarcinomas. Recent studies have identified several human-leukocyte-antigen-restricted epitopes (short peptides) within the CEA protein that can be recognised by human T lymphocytes (T cells). Although CEA-expressing tumour cells are generally weakly recognised by the immune system, several new strategies have been used to enhance immune responses against CEA. This includes using antibodies directed against CEA; inserting the CEA gene into recombinant viruses and bacteria as viral and bacterial vaccines; pulsing the CEA protein, peptides, DNA or RNA onto dendritic cells (specialised antigen-presenting cells); and combining CEA vaccines with cytokines or co-stimulatory molecules to increase vaccine effectiveness. Other factors that might be important in establishing systemic immunity against CEA are the dose, route, timing, and choice of vector and adjuvants for vaccine administration. Further research in understanding the fundamental processes involved in tumour-cell recognition by the immune system, better animal models, and improved clinical trial designs will help to define the full potential of CEA as a target for cancer vaccine development.

The chaperonins are a subgroup of oligomeric molecular chaperones; the best-studied examples are chaperonin 60 (GroEL) and chaperonin 10 (GroES), both from the bacterium Escherichia coli. At the end of the 20th century, the paradigm of chaperonins as protein folders had emerged, but it is likely that during the 21st century these proteins will come to be viewed as intercellular signals. Indeed, it is possible that the chaperonins were among the first intercellular signalling proteins to evolve. During the past few years, it has emerged that chaperonin 10 and chaperonin 60 can be found on the surface of various prokaryotic and eukaryotic cells, and can even be released from cells. Secreted chaperonins can interact with a variety of cell types, including leukocytes, vascular endothelial cells and epithelial cells, and activate key cellular activities such as the synthesis of cytokines and adhesion proteins. Much has been made of the high degree of sequence conservation among the chaperonins, particularly in terms of the immunogenicity of these proteins. However, different chaperonin 60 proteins can bind to different cell-surface receptors, including the Toll-like receptors, suggesting that this family of proteins cannot be treated as one biological entity and that several subfamilies may exist. Chaperonins have been implicated in human diseases on the basis of their immunogenicity. The finding that chaperonins can also induce tissue pathology suggests that they may play roles in infections and in idiopathic diseases such as atherosclerosis and arthritis.

The long-term complications of insulin-dependent diabetes mellitus have become a major health care problem, and it is now clear that they arise from inadequate homeostatic control of blood glucose by injected replacement insulin. Transplantation of pancreatic islets is arguably the most logical approach to restoring metabolic homeostasis in people with diabetes. This review looks at the current status of human islet transplantation and the problems that remain. These include: (1) the limited supply of human islet tissue available for transplantation; (2) the adverse effects of current immunosuppressive protocols on diabetic patients; (3) the problems of primary nonfunction of the transplanted islets; (4) the rejection of islets; and (5) the recurrence of autoimmune diabetic disease. Some of the approaches that might solve these problems are then examined: (1) immune modulation to reduce or prevent immune attack by the recipient's immune system; (2) immunoisolation to prevent recognition of the islet graft; (3) induction of tolerance; (4) xenotransplantation using islets derived from animals; and (5) gene therapy.

Anti-neoplastic cytostatic antiproliferative agents, such as methotrexate, 6-mercaptopurine and cyclophosphamide, were originally used as immunosuppressive drugs. Although these agents induced only modest anti-rejection activity, they caused serious non-specific bone marrow suppression, impairing host resistance and increasing the incidence of infections. Unlike these non-selective agents, cyclosporine A, tacrolimus and sirolimus act more selectively on different stages of the T-lymphocyte (T-cell) and B-lymphocyte (B-cell) activation cycles; however, cyclosporine and tacrolimus are nephrotoxic, whereas sirolimus causes hypertriglyceridaemia. Thus, despite this progress, continued efforts must be made to develop and test new, potentially very selective agents. The agent 15-deoxyspergualin moderately inhibits both mitogen-stimulated T-cell proliferation and the generation of cytotoxic T lymphocytes (CTLs) but does not affect the production of interleukin 2 (IL-2). Another drug, FTY720, has a unique action to prevent rejection, by altering the homing of lymphocytes to the lymphoid compartments. The newest members of the family of antiproliferative agents, namely mycophenolate mofetil, leflunomide and brequinar, are potentially more selective than their predecessors. However, the most promising agents are produced using antisense technology. This approach involves the design of antisense oligodeoxynucleotides; these novel drugs are designed to block allograft rejection by blocking selected messenger RNA (mRNA). This review outlines the mechanisms of action, the limitations of application and the molecular or cellular targets of traditional agents, newly developed drugs and also antisense technology, which is an example of a new application of molecular medicine.

Molecular cytogenetic techniques that are based on fluorescence in situ hybridisation (FISH) have become invaluable tools for the diagnosis and identification of the numerous chromosomal aberrations that are associated with neoplastic disease, including both haematological malignancies and solid tumours. FISH can be used to identify chromosomal rearrangements, by detecting specific DNA sequences with fluorescently labelled DNA probes. The technique of comparative genomic hybridisation (CGH) involves two-colour FISH. It can be used to establish ratios of fluorescence intensity values between tumour DNA and control DNA along normal reference metaphase chromosomes, and thereby to detect DNA copy-number changes such as gains and losses of specific chromosomal regions and gene amplifications. Spectral karyotyping (SKY) is a novel molecular cytogenetic method for characterising numerical and structural chromosomal aberrations. SKY involves the simultaneous hybridisation of 24 differentially labelled chromosome-painting probes, followed by spectral imaging and chromosome classification, and produces a colour karyotype of the entire genome. The use of SKY has contributed significantly to the identification of chromosomal anomalies that are associated with constitutional and cancer cytogenetics, and has revealed many aberrations that go undetected by traditional banding techniques. In this article, we have reviewed these new molecular cytogenetic techniques and described their various applications in molecular medicine.

A dramatic increase in sequence information, both in the form of complementary DNA (cDNA) and genomic DNA, has created a huge gap between the discovery of genes and the process of identifying gene function. To fill this gap, the ‘gene-trapping’ approach has been developed; this combines into a single process the three stages of gene cloning, the study of the pattern of gene expression and the analysis of the respective mutant phenotype. Recent results indicate that gene trapping can be used successfully to clone specific genes that are involved in the development of the central nervous system, limbs and haematopoietic system. Continuous improvements in the design of trapping vectors, faster sequencing of cDNA clones and more-efficient in vitro pre-screening will certainly aid the large-scale trapping of mammalian genomes.

Atomic force microscopy (AFM) is a specialised form of scanning probe microscopy, which was invented by Binnig and colleagues in 1986. Since then, AFM has been increasingly used to study biomedical problems. Because of its high resolution, AFM has been used to examine the topography or shape of surfaces, such as during the molecular imaging of proteins. This, combined with the ability to operate under known force regimes, makes AFM technology particularly useful for measuring intermolecular bond forces and assessing the mechanical properties of biological materials. Many of the constraints (e.g. complex instrumentation, slow acquisition speeds and poor vertical range) that previously limited the use of AFM in cell biology are now beginning to be resolved. Technological advances will enable AFM to challenge both confocal laser scanning microscopy and scanning electron microscopy as a method for carrying out three-dimensional imaging. Its use as both a precise micro-manipulator and a measurement tool will probably result in many novel and exciting applications in the future. In this article, we have reviewed some of the current biological applications of AFM, and illustrated these applications using studies of the cell biology of bone and integrin-mediated adhesion.

Current immunosuppression protocols, although often effective, are nonspecific and therefore hazardous. Consequently, immunological tolerance that is antigen specific and does not globally depress the patient's immune system has become one of the Holy Grails of immunology. Since the discovery that cytokines have immunomodulatory effects, extensive research has investigated the potential of these molecules to induce and maintain specific immunological tolerance in the context of transplantation, allergy and autoimmunity. In this article, we review the possible mechanisms by which cytokines can modulate the immune response and the animal models that frequently confound the theory that a single cytokine, or group of cytokines, can induce tolerance in a predictable manner. Finally, we discuss the role of cytokines at a paracrine level, particularly in the context of inducing and maintaining antigen-specific, regulatory T cells with the clinical potential to suppress specific immune responses.

The glycosphingolipid (GSL) lysosomal storage diseases are a family of human metabolic diseases that, in their severest forms, cause death in early infancy, as a result of progressive neurodegeneration. They are caused by mutations in the genes encoding the glycohydrolases or the activator proteins that catabolise GSLs within lysosomes. In these diseases the GSL substrate of the defective enzyme accumulates in the lysosome, where it is stored and leads to cellular dysfunction and disease. The therapeutic options for treating these diseases are relatively limited; in fact, there are currently no available therapies for most of these disorders. The problem is further compounded by difficulties in delivering therapeutic agents to the central nervous system, which is where the pathology is frequently manifested. To date, research effort has mainly focused on strategies for augmenting enzyme concentrations to compensate for the underlying defect. These strategies include bone-marrow transplantation, enzyme-replacement therapy and gene therapy. Our group has been exploring the alternative strategy of substrate deprivation. This approach aims to balance the rate of GSL synthesis with the impaired rate of GSL breakdown. Studies using an asymptomatic mouse model of Tay–Sachs disease have shown that substrate deprivation prevents GSL storage. In a severe neurodegenerative mouse model of Sandhoff disease, substrate deprivation delayed the onset of symptoms and disease progression, and significantly increased life expectancy. The implications of this research for human therapy have been discussed.