SINDERMANN: INTERNAL DEFENSES OF CRUSTACEA 



eigfn protein. Whether the response is in the 

 form of specific immunoglobulin seems less sig- 

 nificant than the degree of protection afforded 

 to the individual by the adaptive response. In 

 the broadest sense, the replacement of a pro- 

 tective constituent of the hemolymph after its 

 utilization in preventing infection could be con- 

 sidered adaptive. For example, the precipitat- 

 ing factor for foreign jn-otein found by Stewart 

 and Foley (1969) in lobster serum (which de- 

 creases following experimental inoculation of 

 BSA and which is unreactive against injected 

 lobster serum) would be adaptive. 



Considering immune responses of vertebrates 

 and invertebrates. Good and Papermaster stated 

 that the presence in vertebrates of lymphoid tis- 

 sue and cells constitutes a basic distinction. On 

 this basis, as Chadwick (1967) has pointed out, 

 "It is highly unlikely that insects [or Crustacea 

 or other invertebrates] do produce mammalian 

 type antibody, or that the mechanism of any 

 acquired response to antigenic stimulus could be 

 likened to responses in higher animals in terms 

 of the production of specific antibody globulins." 

 Analogous tissues and cells exist in a number of 

 invei'tebrate groups, however, as do analogous 

 humoral res]3onses without the extreme specifi- 

 cities of vertebrate globulins. Chadwick (1967) 

 also stated that the ". . . immune resjionse in an 

 insect is not the consequence of an antigen-anti- 

 body-globulin reaction but more likely the result 

 of the production of some, as yet undefined, 

 principle in insect hemolymph which may con- 

 tribute to its resistance." The same statement 

 might be made about other invertebrates in 

 which an induced response has been demon- 

 strated. 



Although somewhat beyond the confines of the 

 present consideration of internal defenses of 

 Crustacea, it might be well to call attention to 

 recent tissue transplantation work of Cooper 

 (1968, 1969a, 1969b, 1969c, 1969d) with an- 

 nelids, which indicates a high degree of specifi- 

 city of response and which suggests some sim- 

 ilarities to vertebrate tissue graft responses. 

 Cooper's (1969d) concluding statement is sig- 

 nificant: "Further clarification of anamnestic 

 responses to tissue transplants would confirm our 

 views that at least two of the parameters of 



adaptive immunity [in the vertebrate sense], 

 namely specificity and memory, did not evolve 

 exclusively with the lower vertebrates." 



It is obvious that modification, redefinition, or 

 replacement of some conventional immunological 

 terminology — particularly toward broader defi- 

 nitions — is needed if the invertebrates are in- 

 cluded in comparative immunology. If we re- 

 move "antibodies" from invertebrate terminol- 

 ogy we must also remove "antigen," since anti- 

 body response is part of the definition of antigen. 

 An eff'ective substitute for "antigen" (as sug- 

 gested for insects by Hinton) (Chadwick, 1967) 

 would be "immunogen." Chadwick also sug- 

 gested replacement of "antibody" with such 

 terms as "natural bactericidal substance," "spe- 

 cific inducible substance," and others. Further- 

 more, as stated earlier, it must be made clear 

 that when "lysins," "precipitins," "agglutinins," 

 and other humoral factors of invertebrates are 

 discussed, identification with vertebrate factors 

 is not intended — the terms are used merely to 

 indicate the kind of activity produced (i.e., "lytic 

 substance or activity," "precipitating substance 

 or activity," etc.) regardless of the physiological- 

 biochemical mechanism (s) involved. 



When suitably qualified the "safe" general 

 terms, therefore, include "resistance," "immu- 

 nity," "immune response"; terms that can have 

 general applicability and utility, if accepted in 

 a general sense, include "agglutinin," "lysin," 

 "precipitin"; specific vertebrate terminology, 

 not applicable to invertebrates includes "anti- 

 body," "antigen," and "serological." 



Beyond the establishment of working defini- 

 tions of immunity in invertebrates, it seems ap- 

 propriate to list a number of generalizations that 

 seem warranted by the admittedly narrow base 

 of evidence now available. Obviously, any gen- 

 eralization about a group as evolutionarily di- 

 verse as the invertebrates — or for that matter 

 even of the Crustacea — must be in the form of 

 a tenuous and easily retractable hypothesis 

 (which may at times border on speculation), 

 and the following statements are offered with 

 these qualifications: 



1. Resistance in the vertebrates seems pri- 

 marily related to production of immunoglobulins 



477 



