Specific Rejection of Integumentary Allografts by the Sea Star Dermasterias imbricata

Abstract

The origins of well-developed adaptive cell-mediated immune responses in vertebrates would seem to reside among the invertebrates. The work supporting this contention has been extensively reviewed elsewhere (3, 7). Since the immune responsiveness of vertebrates appears to have gone through a step-wise evolutionary development, one would not expect to find specific adaptive immunity widespread throughout all phylums of invertebrates. Indeed, there are few reports in the literature of what appear to be specific cell-mediated immune responses among invertebrates. The studies of Cooper (1) and that of Duprat (2) showed that annelids are capable of specific transplantation immunity with at least short-term memory. Reddy et al. (6) have recently presented evidence that tunicates at the protochordate level are also capable of specific allograft rejection. The data of Hildemann and Dix (4) suggest that at least one representative of the echinoderms, the sea cucumber Cucumaria tricolor, can reject allografts with development of heightened secondary responsiveness. This preliminary study stimulated our further interest in characterizing the immunological potentialities at this level of phylogeny. Thus, we have undertaken extensive studies utilizing the sea star Dermasterias imbricata (class Asteroidea), to ascertain whether or not these animals possess an adaptive immune response as evidenced by specific rejection of integumentary allografts.