Determination of MBL Gene by Using PCR-RFLP and the Study on the Association of Plasma Concentrations of Mannose Binding Protein in Healthy Individuals of Han and Mongolian Population

The aim of this study was to analyze the point mutation of the exon 1 at codon 54 of the mannose ( or mannan)-binding lectin (MBL) gene in healthy individuals of Chinese Hans and Mongolian population, and to find out any association between the plasma levels of MBL and the gene mutation frequency in beth groups of individuals. Blood samples were collected randomly from 56 healthy individuals of Chinese Hans and 37 Mongolian. The detection of the point mutations of the MBL gene was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and detections for plasma levels of MBL were determined by using MBL ELISA kits. A MBL PCR method of assay was established with high specificity, and good reproducibility. By optimizing the PCR condition, the optimal annealing temperature was 55℃, and the lowest detec-tion limit was 160 pg. No bands were found in non-specificity samples (HAV, HBV, HCV and TB), and the sequences of PCR products were the same as the expected ones. Also a MBL PCR-RFIP was established. Upon electrophoresis of the digested products in 3% agarose gel, there were 3 patterns: in which 2 bands correspond to molecule weight 232 bp and 93 bp;1 band, corresponds to molecule weight 325 bp and 3 bands correspond to molecule weight 325 bp, 232 bp and 93 bp, respectively. Three bands of 325 bp, 232 bp and 93 bp of point mutations were found at cedon 54 of MBL ceding gene. Frequencies in healthy Han and Mongolian population were 0. 2321 and 0. 1757 respectively. The average plasma MBL concentration was 1998.750μg/L, with SD of 1505. 152 in 56 healthy Han population and 2525.676μg/L, with SD of 1955. 188 in 37 Mongolian. A negative correlation between MBL concentration and gene mutation frequency was found in healthy Han population. Frequency of point mutation was 1.00 when the MBL concentrations were below 100μg/L; frequency of point mutation was0.4524 when the concentration was 100μg/L to 1000μg/L; and the frequency of point mutation was 0.0156 when the concentration was o