Cd80, also known as B7-1, is a transmembrane glycoprotein belonging to the B7 family. It serves as a crucial costimulatory molecule in T-cell modulation, interacting with ligands such as CD28, PD-L1, and CTLA-4. The CD80-associated pathways play a significant role in immune system regulation, including T-cell activation, immune tolerance, and anti-tumor immune responses [1,3]. Genetic models, like gene knockout (KO) mouse models, are valuable for studying its functions.

In a KO mouse model where cis-PD-L1/CD80 interactions do not occur, tumor immunity and autoimmune responses were greatly attenuated by PD-1. This reveals that CD80 on antigen-presenting cells (APCs) limits the PD-1 coinhibitory signal while promoting CD28-mediated costimulation, highlighting its importance in inducing optimal immune responses [2]. In another study, in CD80-/-mice infected with HSV-1, the absence of CD80 led to increased inflammation and reduced latency but did not affect reactivation, suggesting that modulating CD80 expression could control HSV-induced infection [4].

In conclusion, Cd80 is essential in regulating immune responses, playing a key role in T-cell activation, immune tolerance, and tumor immunity. KO mouse models have provided insights into its role in diseases such as those related to immune evasion like tumor-associated immune modulation and viral-induced immunopathology. Understanding Cd80 functions through these models may offer new strategies for treating related diseases.

References:

1. Sansom, David M, Manzotti, Claire N, Zheng, Yong. . What's the difference between CD80 and CD86? In Trends in immunology, 24, 314-9. doi:. https://pubmed.ncbi.nlm.nih.gov/12810107/

2. Sugiura, Daisuke, Maruhashi, Takumi, Okazaki, Il-Mi, Takemoto, Tatsuya, Okazaki, Taku. 2019. Restriction of PD-1 function by cis-PD-L1/CD80 interactions is required for optimal T cell responses. In Science (New York, N.Y.), 364, 558-566. doi:10.1126/science.aav7062. https://pubmed.ncbi.nlm.nih.gov/31000591/

3. Li, Lanying, Yang, Lei, Jiang, DePeng. 2024. Research progress of CD80 in the development of immunotherapy drugs. In Frontiers in immunology, 15, 1496992. doi:10.3389/fimmu.2024.1496992. https://pubmed.ncbi.nlm.nih.gov/39575257/

4. Jaggi, Ujjaldeep, Ghiasi, Homayon. 2024. Presence of CD80 and Absence of LAT in Modulating Cellular Infiltration and HSV-1 Latency. In Viruses, 16, . doi:10.3390/v16091379. https://pubmed.ncbi.nlm.nih.gov/39339855/