The functions of vitamin D-binding protein (VDBP)
| Function | Relevance to lung and/or systemic disease | Mechanism |
| Vitamin D transportation | Potential influence of levels of vitamin D on host defence and regulation of cell proliferation | Delivery of vitamin D to lung parenchyma and to alveolar macrophages |
| Actin binding | Prevents systemic vascular occlusion following cellular damage. Potential relevance in sepsis and acute lung injury | Prevents formation of F-actin networks in the systemic circulation |
| Neutrophil chemotaxis | Neutrophilic inflammation is a recognised part of COPD and ALI pathogenesis. Neutrophil recruitment is a key part of host defence. | Enhances chemotactic effect of complement-derived peptides |
| Macrophage activation | Macrophage activity is a key part of host defence, and contributes to COPD and ALI pathogenesis | VDBP is converted to macrophage-activating factor by enzymes derived from lymphocytes |
ALI, acute lung injury; COPD, chronic obstructive pulmonary disease.