Disclosed are methods of treating an autoimmune or inflammatory disease using a composition comprising an isolated antibody or an antigen-binding fragment or variant thereof that is capable of binding to muramyl peptide, derivative, analog or salt thereof, wherein said muramyl peptide comprises muramic acid and an amino acid selected from the group consisting of alanine, isoglutamine, glutamic acid and a salt thereof. In one preferred embodiment, the composition can comprise of the isolated antibody or an antigen-binding fragment and one or more therapeutic agents such as Tumor Necrosis Factor (TNF) inhibitor. The autoimmune or inflammatory disease is selected from a group consisting of sepsis, septic shock, Crohn's disease, rheumatoid arthritis, asthma, allergy, atopic disorders, multiple sclerosis, pertussis, gonorrhea, inflammatory bowel disease, and antibiotic associated disorder.