[Partially purified antibacterial polypeptides from granules of human large granular lymphocytes]

This was a study on the antibacterial activity of human large granular lymphocytes (LGL). In our previous work, three antibacterial fractions named HLP-1, HLP-2 and HLP-3 had been identified from the acid-soluble extracts of the granules of LGL by using the gel overlay technique. The present study demonstrated that HLP-1, HLP-2 and HLP-3 separated by preparative acid-urea polyacrylamide gel electrophoresis were potently bactericidal against E. coli MI-35P, S. aureus ATCC 25923, P. aeruginosa ATCC 27853 when tested for their antibacteiral activities by using both agarose radial diffusion assay and gel overlay technique. SDS-PAGE analysis showed that the HLP-3 was almost purified with the molecular weight of 7 kd. The HLP-1 and HLP-2 were more complex, and the ranges of molecular weight were 5.6-13 kd and 5.6-8.8 kd respectively. Our study suggests that the granules of human LGL might contain some low molecular weight antibiotic peptides which play an important role in human innate immunity.