VLA proteins

(= very late antigens)

VLA-1 and VLA-2 were originally defined as antigens appearing on the surfaces of T-lymphocytes 2-4 weeks after in vitro activation; they are now know to be part of the b integrin family. Additional members of the subset are now known (VLA-3, VLA-4, VLA-5 and VLA-6), the b subunits all being identical. Some of the VLA proteins are receptors for collagen, laminin or fibronectin, and many are now known to be expressed on cells other than leucocytes.