Mouse CCL3 (C-C motif chemokine ligand 3, also known as MIP-1α, macrophage inflammatory protein-1 alpha) is a pro-inflammatory chemokine that plays a key role in recruitment and activation of immune cells during inflammatory and infectious responses in mice (Mus musculus). CCL3 primarily signals through the CCR1 and CCR5 receptors, promoting chemotaxis of monocytes, macrophages, dendritic cells, natural killer (NK) cells, and activated T lymphocytes to sites of infection or tissue injury. In mice, CCL3 is produced by activated macrophages, dendritic cells, T cells, epithelial cells, and endothelial cells in response to inflammatory stimuli such as microbial products and cytokines including TNF-α and IL-1β. Mouse CCL3 is widely studied in experimental models of viral and bacterial infections, autoimmune diseases, cancer, and inflammatory disorders, where it contributes to leukocyte recruitment and amplification of immune responses. CCL3 also plays a role in murine models of rheumatoid arthritis, multiple sclerosis (experimental autoimmune encephalomyelitis), and tumor microenvironment regulation, where chemokine-mediated immune cell infiltration influences disease progression. Because mice are the most widely used genetic model for studying immune regulation, characterization of mouse CCL3 has been essential for understanding chemokine-driven leukocyte trafficking, inflammatory signaling, and host–pathogen interactions, providing insights relevant to human immunology and therapeutic development.