Immunity to cartilage proteoglycans

Cartilage proteoglycans constitute a major component of articular cartilage. Humoral and cell-mediated immune responses to these proteoglycans have been observed in various human rheumatic diseases with varying incidences. The possibility of such autoimmune responses being of pathologic significance has been raised by the observation of the induction of arthritis in animals on immunization with proteoglycans. Immunization of BALB/c mice with human cartilage proteoglycan in adjuvant leads to the development of peripheral arthritis as well as spondylitis associated with immune reactivity to mouse cartilage proteoglycan. Pathogenic autoimmune reactions to cartilage proteoglycans may also be elicited by molecular mimicry with bacterial heat shock proteins.