The CD30 (Ki-1) molecule was identified by a monoclonal antibody which was originally found to react with an epitop present in Hodgkin's and Reed-Sternberg cells in Hodgkin's disease. Later, the Ki-1 antigen was found to be consistently expressed by a subgroup of diffuse largecell lymphomas that were called Ki-1 positive (Ki-1+) anaplastic large-cell lymphomas (ALCL). Characterization of the CD30 antigen has shown it to be in its mature form a transmembrane protein of about 120 kDa elaborated from an 84 kDa cytoplasmic precursor primarily through glycosylation. The cloning of the CD30 gene has allowed the identification of a cDNA with an open reading frame predicting a 595 amino acid polypeptide. The extracellular domain of CD30, comprising 365 residues, has proved to be homologous to that of the TNF-receptor superfamily. The CD30 gene is localized at chromosome 1q36, closely linked to other members of the TNF receptor superfamily comprising TNF-receptors, nerve growth factor, CD40, APO-1/Fas, CD27, OX40 and the neurotrophin receptor. The CD30 ligand (CD30L) has been identified, showing significant homology to TNFa, TNFb, FasL, CD40L, CD27L and 4–1BBl. CD30L is expressed on activated T-cells. Interactions of the cytokine receptor CD30 with its ligand induces pleiotropic biologic effects, such as differentiation, activation, proliferation and cell death. In CD30+ ALCL cell lines binding of CD30L induces apoptotic cell death. CD30 furthermore seems to be involved in the control of the CD40/CD40L signal, T-cell proliferation and B-cell maturation induced by T-cell cytokines. Thus, CD30 seems to transmit information that is essential for the immune response. CD30 expression is strictly dependent on activation and proliferation of T- and B-cells. In pathological conditions, CD30 positivity is regarded as a peculiar attribute of Hodgkin's and Reed-Sternberg cells. There is growing evidence for a potential role of the CD30 molecule in clinical use and therapy. An 85 kDa soluble form of the CD30 molecule (sCD30) has been shown to be released by CD30+ cell in vitro and in vivo. It is probably derived from the 120 kDa membrane bound molecule by proteolytic cleavage. Serum sCD30 detection can be regarded as a marker of the amount of CD30+ cells present in the body.
- References to CD30 (Lymphoid activation antigen CD30, Ki-1 antigen)