Antimicrobial activity of histones from hemocytes of the Pacific white shrimp

摘要: The role of vertebrate histone proteins or derived peptides as innate immune effectors has only recently been appreciated. In this study, high levels core H2A, H2B, H3 and H4 were found in hemocytes from the Pacific white shrimp, Litopenaeus vannamei. identified by in-gel digestion, mass spectrometry analysis, homology searching. L. vannamei to be highly homologous histones other species. Based on homology, H2A was cloned its N-terminus resemble known antimicrobial buforin I, parasin, hipposin. Consequently, a 38 amino acid synthetic peptide identical shrimp synthesized assayed, along with endogenous H4, for growth inhibition against Micrococcus luteus. Histone purified homogeneity, completely inhibited Gram-positive bacterium at 4.5 µm while mixture H2B active 3 µm. addition, fraction containing fragment H1 also active. similar submicromolar concentrations. These data indicate, first time, that hemocyte possess activity represent defense mechanism previously unreported an invertebrate. Histones may component immunity more widely conserved, earlier origin, than thought.