The Antibacterial Activity of Haemocyte Clumps in the Gills of the Shore Crab,Carcinus Maenas

Abstract

INTRODUCTIONThe shore crab,Carcinus maenas(L.), rapidly clears bacteria from the circulation to the tissues by virtue of the phagocytic and clumping capacity of circulating haemocytes and fixed phagocytic cells (Smith & Ratcliffe, 1978, 1980a,b; White & Ratcliffe, 1982). If re-infection resulting from the re-entry of sequestered micro-organisms into the circulation is to be prevented then the host must eliminate or incapacitate the foreign particles in some way. The migration of laden host cells to the exterior does not appear to be an important means of disposal of segregated non-self material in the Crustacea (Merril, Mongeon & Fisher, 1979; White & Ratcliffe, 1982), so that the ability to resist infection must reside with the cellular killing capacity, perhaps augmented by humoral antibacterial activity. Indeed, our earlier observations on the disappearance of bacteria fromC. maenasgills seem to indicate that their loss resulted from the lytic action of host haemocytes (White & Ratcliffe, 1982), as does the elimination of micro-organisms from the hepatopancreas of the crayfish,Parachaeraps bicarinatus(McKay & Jenkin, 1970a).