I 309 Human

Human CCL1 was initially identified through subtractive hybridization as a transcript present in a gamma/δ T cell line but not in Epstein-Barr virus (EBV)-transformed B cells . It has been assumed to be a homologue of the mouse TCA3 . The protein is also referred to as I-309 due to its initial identification as a secreted protein derived from activated T cells .

I-309 is a non-glycosylated polypeptide chain containing 74 amino acids, with a molecular weight of approximately 8.5 kDa . The protein is produced in E. coli and purified using proprietary chromatographic techniques . The N-terminal amino acid of the recombinant protein is Lysine .

CCL1 interacts with the chemokine receptor CCR8 to attract monocytes, natural killer (NK) cells, immature B cells, and dendritic cells . This interaction is crucial for the recruitment of Th2 effector cells to sites of allergic mucosal inflammation . High levels of CCL1 have been detected in the serum of patients with atopic dermatitis, and it is constitutively expressed in normal skin .

The CCL1/CCR8 axis is involved in various immune responses, including skin immunosurveillance and the recruitment of immune cells to inflammatory sites . Additionally, CCL1 plays a role in the conversion of CD4 T cells to regulatory T cells (Tregs) in vitro, a process that can be reversed by interleukin-6 (IL-6) . Antibodies against CCL1 have been shown to inhibit the suppressive function of Tregs, suggesting a potential role in immunotherapy .

The neutralization of CCL1 has been explored as an adjuvant to antitumor immunotherapy . The antitumor effect of CpG-ODN plus anti-CCL1 in BALB-neuT mice suggests that targeting CCL1 could enhance the efficacy of cancer treatments .