FISHERY BULLETIN: VOL. 69, NO 



Other negfative findings for increased rate of 

 phage clearance following inoculation in cray- 

 fish were reported by Teague and Friou (1964) . 



Antitoxic Activity 



Little definitive information is available about 

 antitoxic activity in invertebrates. As Huff 

 (1940) pointed out, "Experimental demonstra- 

 tion of antitoxic action in invertebrates has 

 failed for the most part because of lack of 

 susceptibility of invertebrate cells for known 

 toxins." Probably the best example of antitoxic 

 phenomena in Crustacea was described by 

 Cantacuzene (1925a) and Cantacuzene and 

 Damboviceanu (1934a, 1934b). The hermit 

 crab, Eupagin-us prideauxii, exhibited resist- 

 ance to nematocyst toxin of Adamsia palliata. 

 a commensal coelenterate commonly found on 

 the shell of the crab. When injected, the toxin 

 had no effect on E. prideauxii, but it was lethal 

 to many other Crustacea and to a number of 

 other invertebrates tested, including the closely 

 related hermit crab. E. benthardus. Cantacuzene 

 also found that serum of E. piideauxii could 

 neutralize the coelenterate toxin when the two 

 — serum and toxin — were mixed and injected in- 

 to crab species susceptible to the toxin. The 

 development of this antitoxic jsrinciple can be 

 seen as a logical and necessary concomitant of 

 the very close relationship of crab and anemone, 

 but the question of whether this is an example 

 of innate or acquired resistance has not been 

 resolved. 



Another examjile of coelenterate toxin lethal to 

 crabs was reported by Lane, Coursen, and Hines 

 (1961) . Biologically active peptides in Pkysalia 

 nematocyst toxins were tested, using fiddler 

 crabs, Uca pugilntor, as assay animals. 



Except for the work with coelenterate toxins, 

 evidence of antitoxins in invertebrates is weak. 

 Stauber (1961) reported almost immediate re- 

 moval of dij^htheria toxoid from oyster blood, 

 but Metchnikoff (190.5) and Bengston (1924) 

 found that tetanus and botulinus toxins remained 

 in insect body fluids for several weeks without 

 loss of toxicity. These studies must, of course, 

 be viewed as most indecisive, since substances 

 toxic to humans are not necessarily so to inverte- 



brates. Reaction on the part of invertebrates 

 could be identical to i-eaction against any other 

 introduced foreign material. 



Invertebrate responses to gram-negative bac- 

 terial endotoxins were the subject of a review 

 by Levin (1967). The most striking activity 

 of such endotoxins is the pi-oduction, after ex- 

 l)erimental inoculation, of intravascular clots 

 and the ensuing death of various crustaceans 

 and other invertebrates. Antitoxic immunity 

 has not been demonstrated, but, as Levin stated: 

 "Endotoxin appears capable of activating com- 

 plementary defense mechanisms in inverte- 

 brates, including aggregation of amoebocytes, 

 coagulation, bacterial immobilization, and jihago- 

 cytosis. All these may be operative through 

 one tyi^e of cell — the amoebocyte." 



Other Protective Systems 



McKay and Jenkin (1969) examined resist- 

 ance of the Australian freshwater crayfish, Par- 

 achaeraps hicarinatus, to a pathogenic Pseudo- 

 monas sp. and concluded that the animal was 

 capable of an adaptive immune response. Their 

 findings indicated lower mortality rates (after 

 bacterial challenge) in animals inoculated with 

 heat- and alcohol-killed vaccines as well as with 

 endotoxin. Inoculation with vaccines prepared 

 from other gram-negative bacteria also increased 

 the level of resistance to the Pseudomonas in- 

 fection, but vaccines from gram-positive bacteria 

 did not — indicating some degree of specificity. 

 A positive correlation was found between sur- 

 vival of challenged animals and the number of 

 exposures to bacterial antigen; after four inoc- 

 ulations, the LD,-,n of immunized animals was 

 nearly 100 times that of controls. Temperature 

 also played a significant role in the onset, degree, 

 and duration of protection induced by inocula- 

 tion of animals with killed bacteria. At 26° C, 

 onset of protection was rapid ( 1 day) , reached 

 a iieak at 3 days, and almost disappeared by 12 

 days; at 19° C, onset was slower (2 days), 

 reached a maximum at 4 days, and persisted for 

 12 days (the duration of the experiment); at 

 14° C, no protection was afl!"orded. Inoculation 

 of gram-negative endotoxin resulted in protec- 

 tion similar in appearance and duration to that 



470 



