Lobster (Homarus americanus) hemocytes: Classification,differential counts,and associated agglutinin activity

Four hemocyte types were recognized in the lobster based on size and refractile nature of the granules, the ratios of cytoplasm to nucleus, and Giemsa stain characteristics. Two hyaline types were designated as prohyalocytes (1.8%) and hyalocytes (64.2%), and two granular types were termed eosinophilic granulocytes (12.2%) and chromophobic granulocytes (21.9%). There was no significant difference in the percentages of the different hemocyte types (differential hemocyte counts) between sexes, but hyalocyte and eosinophilic granulocyte percentages varied significantly between populations of lobsters. The data suggested that the difference in agglutinin activity (HA) between lobsters with the same total hemocyte numbers was due to activity associated with fixed hemocytes or quantitative differences in HA activity associated with one or more hemocyte types, rather than an increase in the percentage of any one particular type in circulation.