SCALE (SKIN) ALLOGRAFT REJECTION IN PRIMITIVE TELEOST, OSTEOGLOSSUM BICIRRHOSUM

The immune response of the teleost, Osteoglossum bicirrhosum, to scale (skin) allotransplants at 25 C was studied grossly, stereomicroscopically, and histologically. Using allograft pigment cell destruction to determine the survival end point, the soft tissue of first-set allografts was found to be totally rejected relatively slowly compared to higher teleosts, with a mean survival time (MST) of 17.9 days. Second-set allografts were rejected much faster (MST, 5.1 days). Third-party rejection times ranged from 4.3-15.4 days for individual host animals (MST, 10.0 days), thereby revealing a diversity of transplantation antigens in this species. Subsequent invasive reconstitution of first-set allografts by host tissue was confirmed by finding accelerated rejections when the scales were transplanted (reciprocally again) back to the donor animals. The scleroproteinaceous scale plates were also rejected but much more slowly than the soft tissue part of the scale. The soft tissue contains the melanophores on which the above MST data were based. Other manifestations of rejection associated with the destruction of allograft melanophores were also consistently observed including hyperplasia, hemostasis, hemorrhage, lymphoid cell invasion, and host cell replacement of donor tissue. Control autografts survived throughout the period of observation without any morphological sign of incompatibility. © 1969 by the Williams and Wilkins Co.