Meeting Abstract
In response to an acute bacterial infection, the American lobster elicits an immune response allowing for rapid clearance of the bacteria from the circulation. Hemocytes (phagocytic immune cells) are mobilized in the circulating hemolymph and their numbers fluctuate in an inverse manner to hemolymph bacterial numbers during the clearance process. It is clear that the circulating hemocytes participate directly in the clearance process. But, are circulating hemocytes responsible for the bulk of the clearance, or are bacteria sequestered in the tissues and organs as well by fixed hemocytes or by some other means? We employed two methods to assess the role of the hemocytes and tissues/organs in the clearance effort. Whole organ culture was employed to quantify the number of culturable bacteria (i.e., those not engulfed by immune cells) in a tissue/organ. We also employed qPCR to determine the total number of bacterial cells (including non-culturable cells – those that had been engulfed) sequestered by a tissue/organ. The gills have previously been suggested to be of primary importance in hemocyte/bacterial cell sequestration, but our results indicate that other tissues/organs (e.g., heart and antennal glands) may play an even greater role in the immune response.
