The mCD30.1 monoclonal antibody specifically recognizes CD30. CD30 is also known as Tumor necrosis factor receptor superfamily, member 8 (Tnfrsf8). The CD30 molecule is predominantly expressed by activated T lymphocytes, with its expression peaking at day 4-5 on spleen cells activated with plate-bound anti-CD3e antibody. The mCD30.1 antibody reacts with a majority of CD8+ T cells, as well as some CD4+ T cells in these cultures. Expression of CD30 on activated T lymphocytes is regulated by CD28 and cytokines. Its TNF-superfamily ligand, CD30L or CD153, is also expressed on activated T lymphocytes. By northern blot analysis, mouse Cd30 mRNA is detected in the thymus and in 72-hour pokeweed mitogen- and Con A-activated spleen cells, but not in the lung, brain, kidney, liver, bone marrow, unactivated spleen, or 72-hour LPS-activated splenocytes.1 It has also been reported that CD30 is expressed on naive B lymphocytes, it is not detectable after activation, and it starts to return after 72 hours following activation. Reports suggest that signaling through the CD30 molecule may be important in cytokine production by CD8+ CTL lines and may play a role in the regulation of Th1 and Th2 cytokine secretion by CD4+ and CD8+ T cells. It has also been proposed that CD30 plays an important role in the negative selection of thymocytes and protects against autoimmunity. Members of the TNFR family and their ligands are involved in the induction of diverse biological responses in lymphocytes, including differentiation, proliferation, and cellular death. In humans, CD30 was initially identified in Hodgkin and Reed-Sternberg cells in Hodgkin's disease patients and subsequently was found on neoplastic cells of certain types of non-Hodgkin's lymphomas.