Study On Correlation Between LAIR-1(CD305) And Organ Transplantation

LAIR-1/9.1C3 was first discovered in 1983 by Burns' group based on the monoclonal antibody 9.1C3 raised by immunizing mice with human natural killer (NK) cells and its function that 9.1C3 mAb could inhibit the killing of NK cells against K562 cells. The LAIR-1 gene was cloned in 1997 and was named leukocyte associated immunoglobulin-like recepter-1 (LAIR-1) by Meyaard. During the 8^th international Human Leucocyte Differentiation Antigen Congress held in Dec 2004, LAIR-1 was named CD305 as a novel HLDA after its mAb was referred together by Professor Jin Bo-quan of the Fourth Military Medical University (China) and other experts from Oxford University (Britain) and The University of Newcastle (Australian).The gene of LAIR-1 was confirmed to be located within the leukocyte Ig-like receptor complex (LRC) on human chromosome 19q13.4. Its extracellular region contains a single Ig-like domain, whereas the cytoplasmic region contains two immunoreceptor tyrosine-based inhibitouy motifs (ITlMs) which can recruit SHP-1. LAIR-1 is expressed generally on many kinds of immunocells including NK cells, T cells, B cells, dendritic cellsand thymus cells. It has been proved in vitro that cross-linking of LAIR-1/9.1C3 by mAb delivers an intensive inhibitory signal which is capable of inhibiting the functions of NK cells, T cells, B cells and dendritic cell precursors.In this experiment, we used the double mAb sandwich ELISA for detecting the level of sLAIR-1 in samples from clinical organ transplantation patients.The sLAIR-1 molecules were detected to exist in serum and plasma of healthy people, and the content was compared between them. In the after operation time of liver transplantation and kidney transplantation, change of sLAIR-1 was examined and was compared with the expression of mLAIR-1 which was detected by flow cytometry. It was found that the level of sLAIR-1 in allograft patients was significantly higher than healthy people and the level of sLAIR-1 was related with the state and stage of these diseases, whereas mLAIR-1 showed the opposite trend. The serum level of sLAIR-1 dramatically rose in the patients who had opposite accidents after liver and kidney transplantation.lt was the 1st time that we detected sLAIR-1 in the bile which outweighed other transplantation immunity associated cytokines on judging rejection and it also had excellent correlation.Our work may contribute to the following study on immune regulation effect and clinical immune apply of sLAIR-1.