Mindin, also known as Spondin-2 and DIL-1, is a member of the Mindin F-Spondin family of evolutionarily conserved, secreted extracellular matrix proteins. It is composed of an N-terminal F-spondin domain, which mediates integrin binding, and a C-terminal thrombospondin type I repeat, which binds to bacterial lipopolysaccharide (1). Mouse Mindin is synthesized as a 330 amino acid (aa) precursor protein with a molecule weight of approximately 36 kDa (2).  The mature mouse protein shares 88% and 99% aa sequence identity with the human and rat orthologs, respectively (2). Mindin is expressed in a variety of tissues in mice with the highest expression levels being detected in lung, spleen, heart, and lymph nodes (2).

Mindin is essential for initiating innate and adaptive immune responses. It has been shown to be a pattern recognition receptor for bacterial pathogens and function as an opsonin for macrophage phagocytosis of bacteria (1, 2). Mindin also binds directly to influenza virus particles and is necessary for macrophage-dependent clearance of influenza viruses from the nasal cavity (3). In addition, Mindin serves as a ligand for leukocyte integrins (1). It is critical for T cell priming and recruitment of macrophages and neutrophils to sites of inflammation (4, 5). Mindin also regulates trafficking of eosinophils and granulocytes into the airspace and plays a role in the development of allergic airways disease (6, 7). Outside the immune system, Mindin has been shown to promote adhesion and outgrowth of hippocampal embryonic neurons, and to be an important mediator of brain ischemic injury and cardiac hypertrophy (8-11). Furthermore, it has been suggested that Mindin can serve as a marker for prostate and ovarian cancer, as well as diabetic nephropathy (12-14).