Plasma membrane specializations in resting, stimulated and phagocytosing arthropod (Limulus polyphemus, Gromphadorhina portentosa and Blattella germanica) immunocytes: structural and functional analogies with those of vertebrate macrophages and neutrophils.
Using indirect immunofluorescence and scanning electron microscope techniques, we have shown that the plasma membrane specializations, such as pseudopods, filopods, lamellipods, and zeiotic blebs occur in activated and/or phagocytosing arthropod (Limulus polyphemus, Gromphadorhina portentosa, and Blattella germanica) immunocytes (hemocytes), as they do in challenged vertebrate neutrophils and macrophages. All four specializations may also be caused by some of the chemicals in the preparative media, which suggests that arthropod immunocytes, like the vertebrate neutrophils and macrophages, have evolved as highly reactive cells that are sensitive to chemical and/or biological foreign agonists/antigens. These attributes are necessary for the effectiveness of a cellular defense mechanism. The plasma membrane specializations perform the same functions in arthropod immunocytes as reported for those of vertebrates. For example, pseudopods and lamellipods are needed for spreading and locomotion and filopodia for cell adhesion and crawling. Because they are formed as a result of similar reactions to foreign antigens, as in vertebrate cells, it is suggested that similar terminologies be consistently used for them in arthropods.
Gupta
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AP