Immunotoxins: selection of cell-surface antigens and their corresponding monoclonal antibodies

Labeled antigens and antibodies: the evolution of magic markers and magic bullets

The ability to label antigens and antibodies with simple chemicals and even with whole proteins fostered new approaches to basic studies of the immune system as well as new methods of immunodiagnosis and immunotherapy. This was especially true following the introduction of monoclonal antibodies, which enhanced the specificity of many of these applications. The uses to which these labeled immunoreagents were put were legion, and those who employed them might come from any field of biology or medicine. Many of these technical elaborations were critical to progress in immunology and in many other biomedical sciences. They illustrate also the often complex interplay between technology and theory.

Immunotoxins and central nervous system neoplasia

The poor prognosis associated with central nervous system (CNS) malignancy has led investigators to seek new, innovative treatment modalities. Immunotoxins, carrier molecules linked to toxic agents, combine high specificity for tumor-associated antigens with extreme potency. The rationale for both the development of these compounds and for their application to CNS neoplasia is explained. This report discusses the design and construction of immunoconjugates, using toxins that differ in their mechanism of action bound to ligands directed against various antigens. A comparison is made between the in vitro efficacy of standard chemotherapy and immunotoxins in glioblastoma- and medulloblastoma-derived cell lines. A review is included of the results of experiments in animals with leptomeningeal neoplasia, where prolongation of survival following intrathecal administration of immunotoxins has been reported. The obstacles encountered in clinical trials with other types of cancer are addressed and approaches to optimize the use of these novel agents in the context of treating malignant disease of the CNS are suggested.