Surfactant protein D (SFTPD) is a member of the collectin family, primarily synthesized in pulmonary alveolar type II cells and non-ciliated bronchial epithelial cells. It plays a critical role in innate immunity by binding to pathogens, allergens, and apoptotic cells via its carbohydrate recognition domain (CRD), facilitating their clearance through opsonization or aggregation. SFTPD also modulates inflammatory responses by interacting with immune cell receptors, such as calreticulin/CD91. Structurally, it forms multimeric complexes through collagen-like regions, enhancing its functional efficiency.
Antibodies targeting SFTPD are essential tools in studying its biological roles and disease associations. Monoclonal and polyclonal anti-SFTPD antibodies are widely used in immunoassays (e.g., ELISA, Western blot, immunohistochemistry) to quantify protein levels or localize expression in tissues. Dysregulated SFTPD expression or autoantibodies against SFTPD have been implicated in respiratory diseases (e.g., COPD, idiopathic pulmonary fibrosis, ARDS) and autoimmune conditions. Research also explores SFTPD's dual role in infection defense versus potential contribution to chronic inflammation.
Clinically, anti-SFTPD antibodies may serve as biomarkers for disease progression or therapeutic targets. Recent studies investigate engineered antibodies to modulate SFTPD activity in inflammatory disorders. However, challenges remain in understanding isoform-specific functions and reconciling contradictory roles in different pathologies.