Cellular immunity in crustaceans and the proPO system

Effect of lipopolysaccharide on the hemocyte apoptosis of Eriocheir sinensis

“…Interestingly, nearly all the hemocytes experienced an obvious increase in DCF fluorescence after treatment with LPS, especially granule-containing hemocytes, such as semigranulocytes and granulocytes, which are verified to be two major kinds of hemocytes responsible for the storage and release of the proPO system. The active proPO (phenol oxidase) plays an important role in the process of respiratory burst (Johansson and Soderhall, 1989;Johansson et al, 2000). Based on the analysis of flow cytometry, we found that the circulating hemocytes of E. sinensis could be divided into two subpopulations with different DCF mean fluorescences: granule-containing hemocytes and non-granular hemocytes.…”

Stress and immune responses in abalone: Limitations in current knowledge and investigative methods based on other models

“…Sea urchins are of the deuterostome lineage and contain a complement cascade not seen in molluscs but comparable to the vertebrate alternative complement pathway [16][17][18][19][20]. Phenoloxidase testing is useful in investigating immune responses in several invertebrate species including arthropods [21,22] and oysters [23] but has yielded mixed results in immune studies of bacterial infection in abalone [6][7][8][9][10]24] suggesting it is of limited use in this species, at least when dealing with bacterial infection. The immune mechanisms used to deal with bacterial, viral and parasitic infections could be different, and we do not know if phenoloxidase activity is important in parasitic or viral infections in abalone.…”

“…It is well characterised in arthropods [21,22], but has also been investigated in other invertebrate groups, including the bivalves Venus antiqua [118], Mytilus edulis [119] and Perna viridis, where in vitro activation by exogenous proteases has been described, including trypsin, α-chymotrypsin and the detergent sodium dodecyl sulphate [120]. Prophenoloxidase and the activating enzymes are stored in granules in the haemocytes and their release is stimulated when the haemocyte is activated.…”

Ultrastructural aspects of naturally occurring wound in the tunic of two ascidians: Ciona intestinalis and Styela plicata (Tunicata)

“…The massive increment in the number of haemocytes present at the site of wounding after the injection of histamine into the tunic, is consistent with the role that this molecule may play in the regulation of Styela immunity, involving the selective recruitment of effector cells into the tissues (de Barros et al, 2007;García-García et al, 2014). Moreover, the prophenoloxidase system is activated on the wound to produce melanization (Jackson et al, 1993;Johansson and Söderhall, 1989). The prophenoloxidase system is a proteolytic enzyme cascade which recognizes minuscule amounts of cell wall products from microorganisms (lipopolysaccharide, peptidoglycan and glucans) and responds to the microbes by activation of the system and the subsequent generation of immune factors (Cerenius et al, 2008).…”