Invitrogen™ CD101 Monoclonal Antibody (BB27), eBioscience™, Invitrogen™

CD101, also known as the V7 antigen, is a transmembrane glycoprotein and a member of the immunoglobulin superfamily. It is characterized by 7 Ig-like IgV domains and a short cytoplasmic tail with several phosphorylation sites. CD101 forms a disulfide-linked homodimer, although its precise function remains unknown. Expression of CD101 is observed on monocytes, granulocytes, dendritic cells, Langerhans cells, and activated T cells. It is also found on a subset of CD25+Foxp3+ regulatory T cells, which exhibit higher suppressive properties in vitro and in vivo. CD101 plays a role in modulating immune responses. Cross-linking CD101 can antagonize TCR/CD3-mediated lymphocyte activation, while CD101+ CD28+ T cells are highly responsive to CD28 signaling. In combination with anti-CD28 or suboptimal levels of anti-CD3, anti-CD101 can enhance proliferation, suggesting an activating role. The monoclonal antibody BB27 has been shown to inhibit T cell reactivity in allogeneic and antigen-specific mixed DC-T cell cultures. In mice, CD101 is expressed on a subpopulation of regulatory T cells (CD4+, CD25+, Foxp3+) with high suppressor activity. In humans, CD101 expression on peripheral blood mononuclear cells (PBMCs) stains approximately 30% of Foxp3+ cells, although studies have not confirmed higher suppressor activity in the human CD101+ population.