Lair1, also known as Leukocyte-associated immunoglobulin (Ig)-like receptor 1 and CD305, belongs to the family of immune-inhibitory receptors. It is widely expressed on hematopoietic mature cells, especially immune cells. By modulating cytokine secretion and cellular functions, it plays a major negative immunoregulatory role during the differentiation and activation of NK cell and T/B lymphocyte subsets. Four ligands of Lair1, including collagens, have been identified, suggesting its potential immune-regulatory function on the extracellular matrix [1].

In a subcutaneous S. aureus skin infection model, Lair1 knockout (KO) mice had significantly larger abscesses and areas of dermonecrosis compared to wild-type mice. Lair1 KO mice also showed increased inflammatory responses, including elevated production of pro-inflammatory cytokines, myeloid chemokines, neutrophil ROS, and enhanced collagen/ECM remodeling pathways. This indicates that Lair1 may prevent excess inflammatory tissue damage during S. aureus skin infection [2].

In conclusion, Lair1 is an important immune-inhibitory receptor with a major negative immunoregulatory role. Its function in preventing excess inflammatory tissue damage has been revealed through the use of Lair1 KO mouse models, which contributes to our understanding of the role of Lair1 in infectious diseases.

References:

1. Van Laethem, François, Donaty, Lucie, Tchernonog, Emmanuelle, Moreaux, Jérôme, Bret, Caroline. 2022. LAIR1, an ITIM-Containing Receptor Involved in Immune Disorders and in Hematological Neoplasms. In International journal of molecular sciences, 23, . doi:10.3390/ijms232416136. https://pubmed.ncbi.nlm.nih.gov/36555775/

2. Dorando, Hannah K, Mutic, Evan C, Tomaszewski, Kelly L, Mehta-Shah, Neha, Payton, Jacqueline E. 2024. LAIR1 prevents excess inflammatory tissue damage in S. aureus skin infection and Cutaneous T-cell Lymphoma. In bioRxiv : the preprint server for biology, , . doi:10.1101/2024.06.13.598864. https://pubmed.ncbi.nlm.nih.gov/38915487/