Mouse CCL2 (C-C motif chemokine ligand 2, also known as monocyte chemoattractant protein-1, MCP-1) is a pro-inflammatory chemokine that plays a central role in recruitment and activation of monocytes, macrophages, and memory T cells during immune responses in mice (Mus musculus). CCL2 signals primarily through the CCR2 receptor, activating intracellular pathways that promote leukocyte migration, cytokine production, and coordination of innate and adaptive immune responses at sites of infection, tissue injury, or inflammation. In murine models, CCL2 is widely studied in experimental systems of atherosclerosis, autoimmune disease, cancer, neuroinflammation, and metabolic disorders, where monocyte recruitment and macrophage infiltration contribute to disease progression and tissue remodeling. Mouse CCL2 is also critically involved in infectious disease models, including viral, bacterial, and parasitic infections, where it regulates inflammatory cell trafficking to infected tissues. CCL2- and CCR2-deficient mouse models have been instrumental in defining the role of chemokine-mediated monocyte migration in chronic inflammation, tumor microenvironment development, and immune-mediated pathology. As both a biomarker and functional mediator of monocyte recruitment, mouse CCL2 remains a key molecule in preclinical research investigating inflammatory signaling pathways and development of chemokine-targeted therapies relevant to human disease.