CD81/TAPA1: I'm on Tapa the Cell

Fri, 06/13/2014 - 10:07

Target of the antiproliferative 1 (TAPA1), also known as CD81, is found in the plasma membrane in lymphocytes and plays an important role in the regulation of lymphoma cell growth. This transmembrane 4 superfamily (TM4SF) protein is primarily found on CD4+CD8+ thymocytes as well as broadly in the periphery, with high-level expressed in cell cohorts such as B-cells, NK cells, macrophages, and dendritic cells. CD81 appears to be involved in a variety of cellular immune processes such as activation, proliferation, and differentiation. It is believed to act as a viral receptor for HCV. Mutations affecting CD81 cause immunodeficiency - characterized by antibody deficiency, recurrent bacterial infections, and hypogammaglobulinemia. The activation of T-cells induces CD81 upregulation. Yoshie’s group at the Shionogi Medical Institute developed the M38 clone of the CD81 antibody in 19921.This group also demonstrated that the CD81 antibody inhibited synctium formation in response to HTLV-1 in human T-cells but not in osteosarcoma lines. These scientists also performed CD81 antibody immunoprecipitations in their detailed associated protein complex assessments, and found that both CD81 and TM4SF are regularly associated with CD4 or CD8 in T-cells2.

Immunocytochemistry/Immunofluorescence: CD81 Antibody Immunocytochemistry/Immunofluorescence: CD81 Antibody

Further molecular analyses with the CD81 antibody allowed Imai et al to demonstrate that CD4 exists in two physical states – one of association with p56lck and another of association with TAPA-1 or CD823. The CD81 antibody was used by Escola’s group in the Netherlands to demonstrate that exosomes are enriched in many tetraspan proteins such as CD37, CD53, TAPA-1, and CD824. They believe this biased protein distribution is driven through active protein sorting which needs to be further investigated.

Novus Biologicals offers CD81 reagents for your research needs including:


  1. 17138199
  2. 8245480
  3. 7636191
  4. 9685355

Blog Topics