Acceptance and Regression of a Strain-specific Lymphosarcoma in Mexican Axolotls

Abstract

A closed colony ³ of dark (DD) and white (dd) Mexican axolotls (Ambystoma mexicanum) was analyzed, by skin allografting, for acceptance or rejection. From this analysis three major histocompatibility factors were identified and designated A^h, B^h, and C^h (1, 2). These factors behave as codominants and segregate as would be expected (2), thus: B^hB^h × C^hC^h → B^hC^h × B^hC^h → ¹/₄B^hB^h: ¹/₂B^hC^h: ¹/₄C^hC^h. Although the factors may turn out to be complex, they appear to berelatively rapid within the context of chronic rejection characteristic of urodeles. The onset of rejection occurs at 28 days ± 7 days. In addition to these factors, there are relatively “weak” factors that may produce chronic rejection initiated at about 90 days or later; no attempt has yet been made to analyze these in detail. Rapid chronic rejection has the characteristic manifestations (Plate I, upper left and right) described for several amphibia (4, 5, 6, 7): there is epidermal hyperplasia in the graft and replacement from the edges by the host’s epidermis; if the graft is pigmented, the epidermal cells become punctate but if the graft is unpigmented on a pigmented host, the host’s epidermal melanocytes move in with the replacing epidermis; there is marked vasodilation which is almost always followed by stasis and disintegration of the vascular bed.

Supported by Public Health research grant GM15 3 63-02 from the Institute for General Medical Sciences.

The assistance and involvement of Mr. Sven Warner in the execution of the experiments is gratefully acknowledged.