Plays a role in the regulation of innate resistance to pathogens, inflammatory reactions, possibly clearance of self-components and female fertility. Homooctamer; disulfide-linked (PubMed:18223257). Binds to C1q (By similarity). (Microbial infection) Interacts with SARS coronavirus-2/SARS-CoV-2 Nucleoprotein and Spike protein homotrimer. By IL1B/interleukin-1 beta and TNF. Glycosylated.