Human lectins and their roles in viral infections.
Mannose-binding lectin (MBL) is a Ca⁺² -dependent collagenous lectin, that is produced by liver and mediates innate immune responses by opsonization of pathogens. The serum level of MBL varies widely among healthy individuals, ranging from 0.05 µg/ml (or lower) to over 5 µg/ml, mainly depending on genetic variation. This study has examined promoter and exon 1 of mbl2 genotype among 117 Iranian healthy blood donors. MBL Single Nucleotide Polymorphisms (SNPs) were genotyped using polymerase chain reaction (PCR), and serum levels of MBL were quantified using a double-antibody enzyme linked immunosorbent assay (ELISA). Results of this study showed that there are two promoter polymorphisms at -550 (H/L variants) and -221 (Y/X variants) positions, and three polymorphisms in exon 1 at codon 52 (D Allele), 54 (B Allele), and 57 (C Allele) in this population. B allele was significantly correlated with the lowest serum MBL level. Our results also showed that the most frequent genotype was HYA/LXA, and the genotype that associated with the highest serum level of MBL was HYA/HYA. The genotype that causes lowest MBL production in Iranian population was LYB/LXA. These results showed some differences compared to that of the other populations. To verify the originality of these differences we may need to extend the study to a larger samples of respective populations; meanwhile the importance of a new mutation, nucleotide 101 of MBL2 exon1, reported in the current study should be taken in considerations in terms of its possible pathobiological effects in following studies.