The economic importance of the American lobster (Homarus americanus) in New England and Atlantic Canada, coupled with recent environmental and anthropogenic challenges, has made developing a deeper understanding of the lobster innate immune system increasingly important. Lobsters and other crustaceans shed their shells during the process of molting; during this cycle, animals are subject to stressors that can lead to an immune response. The lobster immune system relies on hemocytes found in the circulatory fluid (hemolymph), with the production and secretion of soluble antimicrobial peptides (AMPs) playing an important role in the immune response. AMPs are of particular interest because of their potential impact upon pathogens and as potential indicators to forecast disease state; however, relatively few antimicrobial compounds have been fully characterized from the lobster. We have used a chip-based nanoLC-MS/MS analysis to identify several AMPs in H. americanus, including a beta-defensin-like putative antimicrobial peptide, H. americanus defensin 1 (Hoa-D1) and several putative crustin-family peptides in hemocytes. We have fractionated hemocytes and studied the localization of the identified AMPs to semigranulocytes and granulocytes. In this study, we report on changes to hemocytes (numbers and composition) and AMP composition throughout three stages of the molt cycle (intermolt, pre-molt, and post-molt).

Antimicrobial peptides (AMPs) in the American lobster, Homarus americanus: Changes to hemocytes and AMPs as a function of molt status

2019 Spring National Meeting

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