Analysis Of MASP-2 Gene A Point Mutation At Codon P.D105G And Its Plasma Levels In Healthy Population In Beijing Yanqing

Mannose combine agglutinin(mannan binding lectin, the MBL) is the key molecule in innate immunity. It recognizes carbohydrate patterns that expressed on the surface of a large number of pathogenic micro-organisms. Binding of MBL to a micro-organism results in activation of the lectin pathway of the complement system, similar to the classic pathways of C1 r and C1 s. In these process, the MBL associated serine protease(the MBL- associated serine protease, MASP) fixes the complement component. Once it is activated, MASP cuts the downstream components and induces a waterfall effect, resulting in the removal of exogenous foreign body that is mediated by the dissolved compounds assembled by the complement components, or by phagocytosis.MASP belongs to the serine protein kinase family, so far, five members are reported, including MASP1, MASP2, MASP3, MAP19 and MAP44. MASP and MBL coexist in the form of complex. MBL binds to the N-galactosamine or mannose on the surface of microorganisms, after that activated MASP further activates the complement and induces the associated biological effect.MASP-2 gene is located on chromosome 1 p36. 23-31, coding MAP19 and MASP-2. The MBL pathways plays an important role in immune prevention and immune surveillance. The well-organized composition of MBL pathway directly influences the immune function,resulting in the disease development and recovery. The mutation of MASP-2 can lead to the dysfunction of the MBL pathway. It has been reported that there are several single nucleotide polymorphisms(SNPS)in MASP2, such as rs72550870(p. D120G),rs12711521(p. D371Y),rs2273346(p. V377A). MASP-2 gene polymorphism is related to its expression. It has been found that in Hong Kong of China, these individuals with the repeated mutation in the 4 amino acids in the site of156 ~ 159 of MASP-2 always showed low levels of MASP-2. Thus, it is important to understand the correlation between the genetic polymorphism of the MBL pathway(MBL 、 MASP-2) and the susceptibility to disease which is also the hot area for immune genetics and human genomics research. It has been reported that the MBL gene polymorphisms is associated with a variety of autoimmune diseases.Therefore, it is worth investigating the correlation of genetic polymorphism of MASP-2, the downstream molecule for MBL pathway,with certain diseases.In this study, 112 blood samples from health donors were collected from Yanqing district in Beijing. Plasma and DNA were isolated.Secquence specific primer –PCR(SSP-PCR) and electrophoresis were employed to detect the point mutation at p.D105 G in MASP-2 gene,and results demonstrated that 112 cases were all wild type.The concentration of MASP2 in plasma were detected using MASP-2 ELISA kit and results showed that their average concentrationwas 303.88 ng·m L-1, with median and interquartile were 257.99 and 348.68 ng·m L-1 respectively.Further studies found that there was significant correlation between MASP-2 concentration and gender, but not for age. With these studies, it will be helpful in exploring the relationship between MASP-2 mutation resulting in repeat infection and clinical related diseases, and pave the way to better understanding the molecular genetic regulation of MASP2.