Disclosed is an isolated antibody or an antigen-binding fragment thereof The antibody is capable of binding to a muramyl peptide, or a derivative or an analog or a salt thereof. The muramyl peptide comprises muramic acid and an amino acid selected from the group consisting of alanine, isoglutamine, glutamic acid, and a salt thereof. Also disclosed are methods of producing the antibody, compositions comprising the antibody, methods of treating using the antibody, uses of the antibody, methods of detecting muramyl peptide, an assay for detecting muramyl peptide, an antibacterial agent, hybridomas and kits.