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Granular hemocytes are phagocytic, but agranular hemocytes are not, in the Eastern Oyster Crassostrea virginica

Gary H. Wikfors
  • Northeast Fisheries Science Center, NOAA Fisheries Service, 212 Rogers Avenue, Milford, CT 06460, USA,
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Jennifer H. Alix
  • Northeast Fisheries Science Center, NOAA Fisheries Service, 212 Rogers Avenue, Milford, CT 06460, USA,
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
Published Online: 2014-03-10 | DOI: https://doi.org/10.2478/invim-2014-0001


Hemocytes in oysters are known to be involved in the innate immune response to pathogenic bacteria and parasitic protozoa; some hemocytes are phagocytic and capable of killing invading microorganisms through intracellular ROS and proteolytic enzyme release into phagosomes. Although this activity has been associated for some time with granular hemocytes – cells with ROS- and enzyme-producing granules – the possible roles of agranular hemocytes in oysters have remained obscure. One hypothesis, that agranular hemocytes are phagocytic despite the lack of granules, was tested in the present study by sorting granular and agranular hemocytes from adult oysters into separate test tubes with a sorting flow cytometer and conducting a routine phagocytosis assay using analytical flow cytometry. Sorting of functional granular hemocytes was necessary, because in a mix, phagocytic agranular cells could become granular after incorporation of bacterial or other particles. Granular hemocytes were phagocytic before and after sorting, and agranular hemocytes were not phagocytic before or after sorting. We relate this finding to developing hypotheses about the origins and roles of different hemocyte types in oysters.

Keywords: bivalve mollusk; cell sorting; flow cytometry; granulocyte; innate immunity


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About the article

Received: 2013-11-08

Accepted: 2014-01-08

Published Online: 2014-03-10

Citation Information: Invertebrate Immunity, Volume 1, Pages 15–21, ISSN (Online) 2084-767X, DOI: https://doi.org/10.2478/invim-2014-0001.

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©2014 Gary H. Wikfors and Jennifer H. Alix. This article is distributed under the terms of the Creative Commons Attribution Non-Commercial No-Derivatives License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. BY-NC-ND 3.0

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