title: Establishment of an ELISA system for determining soluble LAIR-1 levels in sera of patients with HFRS and kidney transplant.
abstract: LAIR-1, the leukocyte-associated Ig-like receptor-1, is a trans-membrane molecule that functions as an inhibitory receptor on natural killer cells, T lymphocytes and monocytes. It has been well known that many trans-membrane receptors can shed from the cell surface and be released into the circulation in soluble form when lymphocytes, endothelials and other immune cells are activated. In many cases, the levels of soluble receptors in the circulation can be used as markers of lymphocyte activation in transplant patients and virus infection patients. To investigate whether LAIR-1 is able to be released into the sera, we developed a sandwich enzyme-linked immunosorbent assay (ELISA) system based on two anti-LAIR-1 monoclonal antibodies (MAb) with different epitope specificities. Using this ELISA, we found that sLAIR-1 existed in the supernatants collected from PMA, PHA or CD3 MAb-stimulated lymphocytes cultures in vitro for the first time. Moreover, we found that LAIR-1 level in serum samples from healthy individuals was 6.2 +/- 3.3 ng/ml, whereas the levels in sera of patients with hemorrhagic fever with renal syndrome (HFRS) and patients 3-7 days after kidney transplant increased to 47.2 +/- 35.9 and 24.4 +/- 16.0 ng/ml, respectively. Furthermore, HFRS patients in oliguric phase showed higher serum sLAIR-1 levels than those in other phases, and transplant patients with rejection showed higher serum sLAIR-1 level than those without rejection. These findings demonstrated that LAIR-1 can be released when lymphocytes are activated, suggesting sLAIR-1 may be used as a predictor for monitoring immune reaction in some virus infections and organ transplants which may be useful in clinical treatment of these diseases.
authors.affiliation: Department of Immunology, Fourth Military Medical University, Chang Le West Road 17, Xi'an, Shaanxi Province 710032, China.
authors.forename: Weiming
authors.initials: W
authors.lastname: Ouyang
authors.forename: Jiangnan
authors.initials: J
authors.lastname: Xue
authors.forename: Jingmei
authors.initials: J
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Jia
authors.forename: Zhouli
authors.initials: Z
authors.lastname: Li
authors.forename: Xin
authors.initials: X
authors.lastname: Xie
authors.forename: Xuesong
authors.initials: X
authors.lastname: Liu
authors.forename: Jinlong
authors.initials: J
authors.lastname: Jian
authors.forename: Qi
authors.initials: Q
authors.lastname: Li
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhu
authors.forename: Angang
authors.initials: A
authors.lastname: Yang
authors.forename: Boquan
authors.initials: B
authors.lastname: Jin
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D019556:COS Cells; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006084:Graft Rejection; D006480:Hemorrhagic Fever with Renal Syndrome / Q000276:immunology*; D006801:Humans; D016030:Kidney Transplantation / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000737:chemistry; D011971:Receptors, Immunologic / Q000097:blood* / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D011971:Receptors, Immunologic; D011993:Recombinant Fusion Proteins; C108073:leukocyte-associated immunoglobulin-like receptor 1