This antibody recognizes extracellular part of CD30, a 105 kDa single chain glycoprotein expressed on Hodgkin's and Reed-Sternberg cells. It is also found in Burkitt's lymphomas, virus-infected T and B lymphocytes, and on normal B and T lymphocytes after activation (T lymphocytes that produce Th2-type cytokines and on CD4+/CD8+ T lymphocytes that co-express CD45RO and the IL4 receptor).