Ccr7, a chemokine receptor, is a G protein-coupled receptor with 7 transmembrane domains. It plays a crucial role in the immune system by guiding the migration of various immune cells such as naive T/B cells, central memory T cells, regulatory T cells, immature/mature dendritic cells (DCs), natural killer cells, and some tumor cells. It functions through interaction with its ligands CCL21 and CCL19, which are involved in pathways related to immune cell trafficking, antigen presentation, and T-cell response [1,2,4,6].

Genome-wide association studies (GWAS) have shown a strong link between the CCL21/CCR7 axis and disease severity in autoimmune diseases like rheumatoid arthritis, sjogren's syndrome, systemic lupus erythematosus, polymyositis, ankylosing spondylitis, and asthma. Disrupting the CCL21/CCR7 interaction can prevent the migration of CCR7-expressing cells to the site of inflammation, reducing disease severity [1]. In cancer, the CCR7 axis has a dual role. It can be involved in the trafficking of effector cells against tumors, but also in the migration of tumor cells to the lymphatic system and metastasis [2]. In blood cancers, CCR7 expression often correlates with nodal or spleen involvement [3]. In early Xenopus embryogenesis, ccr7 affects morphogenesis and cell differentiation [5].

In conclusion, Ccr7 is essential for immune cell migration and immune responses. Studies related to gene-knockout models (although not specifically detailed in the given references) could potentially further clarify its role in the contexts of autoimmune diseases, cancer, and early development. Understanding Ccr7 provides insights into the pathogenesis of these diseases and may offer potential therapeutic targets.

References:

1. Han, Le, Zhang, Lingling. 2023. CCL21/CCR7 axis as a therapeutic target for autoimmune diseases. In International immunopharmacology, 121, 110431. doi:10.1016/j.intimp.2023.110431. https://pubmed.ncbi.nlm.nih.gov/37331295/

2. Salem, Anwar, Alotaibi, Mashael, Mroueh, Rima, Basheer, Haneen A, Afarinkia, Kamyar. 2020. CCR7 as a therapeutic target in Cancer. In Biochimica et biophysica acta. Reviews on cancer, 1875, 188499. doi:10.1016/j.bbcan.2020.188499. https://pubmed.ncbi.nlm.nih.gov/33385485/

3. Cuesta-Mateos, Carlos, Terrón, Fernando, Herling, Marco. 2021. CCR7 in Blood Cancers - Review of Its Pathophysiological Roles and the Potential as a Therapeutic Target. In Frontiers in oncology, 11, 736758. doi:10.3389/fonc.2021.736758. https://pubmed.ncbi.nlm.nih.gov/34778050/

4. Hong, Wenxiang, Yang, Bo, He, Qiaojun, Wang, Jiajia, Weng, Qinjie. 2022. New Insights of CCR7 Signaling in Dendritic Cell Migration and Inflammatory Diseases. In Frontiers in pharmacology, 13, 841687. doi:10.3389/fphar.2022.841687. https://pubmed.ncbi.nlm.nih.gov/35281921/

5. Goto, Toshiyasu, Michiue, Tatsuo, Shibuya, Hiroshi. 2022. ccr7 affects both morphogenesis and differentiation during early Xenopus embryogenesis. In Development, growth & differentiation, 64, 254-260. doi:10.1111/dgd.12790. https://pubmed.ncbi.nlm.nih.gov/35581152/

6. Brandum, Emma Probst, Jørgensen, Astrid Sissel, Rosenkilde, Mette Marie, Hjortø, Gertrud Malene. 2021. Dendritic Cells and CCR7 Expression: An Important Factor for Autoimmune Diseases, Chronic Inflammation, and Cancer. In International journal of molecular sciences, 22, . doi:10.3390/ijms22158340. https://pubmed.ncbi.nlm.nih.gov/34361107/