Meeting Abstract
Hemocytes circulate through the open circulatory system of gastropods as non-adhesive cells, which rapidly become adhesive and aggregate as nodules when exposed to foreign materials. The binding and subsequent elimination of microbes by hemocytes is an important part of the innate immune response in mollusks. We address two aspects of this response in the giant keyhole limpet. First, when hemolymph was mixed in vitro with two microbes (Vibrio fisheri and Bacillus subtilis) there was a rapid decrease in the concentration of both bacteria. In addition, there was a decrease in the number of nodules produced due to growth of individual nodules and the fusion of smaller nodules. Presumably, hemocytes binding to the outer surface of growing nodules continued to collect microbes in circulation. Second, stages in the phagocytosis and degradation of the microbes are described. After five minutes of nodule formation, the aggregates could be readily observed by eye. These nodules were transferred from the hemolymph sample containing bacteria to fresh plasma in which the hemocytes had been removed by centrifugation. The capture, phagocytosis and degradation of the microbes in these nodules is described based on SEM and TEM examination.
