R&D Systems offers products for additional carbohydrate-binding proteins that are not members of the C-type lectin, galectin, Ig-type lectin, selectin, or hyaluronan families. These products include intelectin-1 and -2, and pentraxins (PTX) 2 and 3. Intelectin-1 is a 40 kDa Ca2+-dependent galactofuranose-binding lectin that is not a C-type lectin. It is expressed on multiple cell types and appears to participate in insulin signaling and microbe recognition. Intelectin-2, likely a Ca2+-dependent carbohydrate-binding lectin that is a member of the X-lectin family of molecules, is secreted by intestinal Paneth cells and appears to participate in fungal microbe recognition.
Pentraxins have a characteristic pentagonal discoid arrangement of five non-covalently bound subunits and bind a variety of molecules in a Ca2+-dependent lectin-like manner through a pattern-recognition-binding site. PTX2 is a major acute-phase protein and may function as an opsonin for a variety of ligands. PTX2 also associates ubiquitously with all amyloid deposits implicated in diseases including Alzheimer's disease and prion diseases, type 2 diabetes and various systemic amyloidoses. Pentraxin 3 (also known as TSG-14) was initially identified as a TNF-alpha or IL-1 beta inducible gene. In addition, the concentration of PTX3 is elevated in the joint fluid of patients with rheumatoid arthritis, suggesting that PTX3 may be a potential mediator of the immune response.