Pattern recognition receptor (PRR) which binds Gram-positive and Gram-negative bacteria (PubMed:9468508). Also plays a role in binding of unopsonized particles by alveolar macrophages (By similarity). Binds to the secretoglobin SCGB3A2 (PubMed:12847263). {ECO:0000250|UniProtKB:Q9WUB9, ECO:0000269|PubMed:12847263, ECO:0000269|PubMed:9468508}. This is the function of MARCO (macrophage receptor with collagenous structure, ENSG00000019169).