FISHERY BULLETIN: VOL. 69, NO. 3 



rus striatum, which is closely related to Eiijxig- 

 unis prideauxii. 



Cantacuzene (19231)), summarizing- a decade 

 of study of humoral defenses in invertebrates, 

 found that the serum of the spider crab, Main 

 squlnado, possessed natural agglutinins for 

 mammalian red blood cells, with great individual 

 variation from crab to crab. He observed, rather 

 significantly, that agglutinins weakened or dis- 

 appeared completely in crabs held in captivity 

 for long periods. He noted, on injection of eryth- 

 rocytes, that agglutinins disappeared com- 

 pletely during the first days after inoculation 

 and did not return to their original titer for 

 several weeks after the last dose. Cantacuzene 

 also reported that rare individuals of Maia. — in- 

 variably moulting females — possessed a lysin for 

 mammalian red blood cells. Maia serum also 

 possessed a strong lytic factor, but no aggluti- 

 nins, against cholera vibrios. 



Cantacuzene inoculated Maia with coelomic 

 fluid of Sipimculus midus (4 to 5 injections at 

 intervals of 3 to 5 days) and found that the crabs 

 produced first agglutinins and then lysins against 

 the various injected sipunculid coelomic cells, 

 including ova. The nature, intensity, and dura- 

 tion of response varied greatly among indivi- 

 duals. The lytic ability seemed more pronounced 

 in females than in males, and more so in fe- 

 males approaching sexual maturity. Hemolysins 

 against mammalian erythrocytes were also pro- 

 duced. 



When he comi)ared the lytic ability of Maia 

 serum after injection with sipunculid fluid and 

 mammalian erythrocytes, Cantacuzene found 

 that response was more rapid and stronger with 

 the former, and he concluded — on the basis of 

 these and other studies — that mammalian red 

 cells were only mediocre antigens for marine in- 

 vertebrates. He attributed this weak antige- 

 nicity to coating of the injected mammalian 

 erythrocytes in Maia and other invertebrates 

 with a serum factor that interfered with sub- 

 sequent reactions. Cantacuzene a])tly referred 

 to this as "mummification" of the red cells by 

 invertebrate body fluids. 



Concerning acquired immunity to bacterial 

 infections in Crustacea, Cantacuzene (1923b) 

 found that the crab Maia squinado, when inoc- 



ulated with killed Vibrio choleme or small doses 

 of live vibrio, was able — 12 days after the fifth 

 injection — to survive the challenge with 20 times 

 the dose of vibrio which had proved fatal to un- 

 inoculated control crabs. 



Cantacuzene also reported on studies of the 

 responses of Maia squinado to injections of gram- 

 positive bacteria isolated from the crab's diges- 

 tive tract. Inoculation was followed by reduc- 

 tion in numbers of amebocytes and, within 24 hr, 

 by disappearance of most of the bacteria from 

 the hemolymph. The bacteria were immobilized 

 in the various i^hagocytic tissues, particularly 

 in the branchial lacunae — at first they adhered 

 to the cell surfaces, then amassed into small 

 granules, and were finally engulfed by fixed and 

 mobile phagocytes. The process of digestion of 

 bacteria was slow, and still incomplete after 7 

 weeks. Clotting ability of the hemolymph de- 

 creased immediately after inoculation but re- 

 turned to normal in 8 days. Xo agglutinins for 

 the bacteria could be demonstrated in vitro, but 

 the natural agglutinins for mammalian red blood 

 cells (discussed earlier) disappeared. In vitro 

 studies disclosed that the hemagglutinin coated 

 the bacteria but did not cause their agglutination. 

 The adherence in vivo of the bacteria to fixed 

 phagocytic cells undoubtedly was enhanced by 

 the sensitization. Some evidence for this was 

 gained by adding macerated hypodermal or peri- 

 cardial cells to a mixture of bacteria and crab 

 serum in vitro. The cell fragments acted as 

 centers for bacterial agglutination and immobili- 

 zation, but the agglutinating ability was not 

 conferred on the serum by the addition of cell 

 fragments. 



A diflferent sequence of events was described 

 for those crabs (Maia) in which the experimental 

 infections progressed to death. Early immobili- 

 zation of bacteria in lacunar cells was followed, 

 in 8 to 15 days, by the appearance of encapsu- 

 lated forms, invulnerable to destruction by 

 phagocytes. The encaj^sulated bacteria multi- 

 plied, phagocyte numbers were reduced, and the 

 clotting ability of the hemolymph diminished. By 

 10 to 20 days after inoculation, the hemoljTnph 

 became incoagulable, the natural agglutinin for 

 red cells disappeared, the connective tissue be- 

 came gelatinous, and the animal died. 



464 



