Lipopolysaccharides (LPS), derived from Escherichia coli O55:B5, are essential components of the outer membrane of Gram-negative bacteria. Composed of lipid A, a core oligosaccharide, and an O-specific polysaccharide, LPS exhibits strong immunogenicity. It activates immune cells via the TLR4 receptor, induces chemotactic cell migration and cytokine secretion, and helps maintain the integrity of the bacterial outer membrane, protecting against bile salts and lipid-based antibiotics. LPS is commonly used to establish inflammatory models, including arthritis, chronic obstructive pulmonary disease (COPD), acute respiratory distress syndrome (ARDS), and gastrointestinal disease models.

Collagen, Type II (derived from bovine snout cartilage), is a homotrimeric helical protein composed of three identical α1(II) chains and is a major component of animal cartilage. It possesses multiple biological activities, including maintaining cartilage tissue integrity, inducing immune tolerance, and promoting chondrocyte growth and redifferentiation. It is commonly used to induce collagen-induced arthritis (CIA) models and has demonstrated significant efficacy in alleviating pain and inflammation associated with collagen-induced arthritis in mice, making it widely applicable in osteoarthritis-related research.

CP-20961 is an effective synthetic non-immunogenic adjuvant that can be used to induce acute and chronic arthritis models.

Complete Freund's adjuvant (CFA) is an immunologic adjuvant emulsified with antigens, composed of heat-killed, inactivated Mycobacterium tuberculosis in a water-in-oil emulsion with paraffin oil. As a TLR ligand, it enhances the immune response to antigens in animals, induces Th1-type immune responses, and is commonly used to establish experimental models such as rheumatoid arthritis, persistent inflammatory pain, and experimental autoimmune myocarditis (EAM) in rats.

G6PI 325-339 (human) is an effective reagent for inducing arthritis in B10.Q mice. It triggers cross-reactive Th1 and Th17 cell responses against the mouse G6PI protein and can be used to induce an arthritis model through T and B cell-dependent pathways, although it does not involve antibody-mediated mechanisms.