The Study On Human Antimicrobial Pepetide LL-37/hCAP-18

The antimicrobial peptides of innate immunity are first line of host defense against pathogenic microorganisms. Antimicrobial peptides have received increasing attention because they are being evaluated as possible alternative to conventional antibiotics and having potential application on plant resistant gene engineering. LL-37 is the unique amphipathic α-helical AMP isolated from human source, which belongs to cathelicidin family. Both purified and chemically synthesized LL-37 exhibits potent and comparable antimicrobial activity against Gram-negative and Gram-positive bacteria. It also has the ability to bind lipopolysaccharide (LPS) and neutralizing biological activity in vitro and reduces its lethality in murine models of endotoxaemia by. All these findings support that the LL-37 might have therapeutic potential for the treatment of bacterial infection. We examined the expression of LL-37/hCAP-18 in a panel of hematopoietic cell lines representing multiple cell lineages. LL-37/hCAP-18 expression at mRNA level was detected and varied among 6 of 9 cell lines. The expression of Raji cells was about 8 folds higher than that of Ramos cells. However, only two cell lines, J6-1 and U937, expressed protein products. We also investigated LL-37/hCAP-18 protein in 9 leukemia and 3 ITP patients via immunocytochemical staining. The rate of LL-37/hCAP-18 positive cells ranged from 60% (ITP) to 0.5% (M5). These data suggested that the low translation efficiency of LL-37/hCAP-18 expresses in some leukemia cells might be one of...