© 1978 by The Society for Integrative and Comparative Biology
Immunogenetic Profile of the Axolotl: 1977
Department of Biology, Ithaca College Ithaca, New York 14850
SYNOPSIS. As with mammals, the ability to test questions of an immunogenetic nature in the axolotl and other amphibia is greatly enhanced by the use of defined, inbred genetic lines. These have been developed and at present qualify as partially inbred strains; there are 7, with the most highly inbred being at present at F13. During the development of these strains, several questions have been tested. A question of evolutionary interest is whether the amphibia show the equivalent of a major histocompatibility complex (MHC). The anurans do but there remains a question of whether any one histocompatibility locus is predominant in urodeles; suggestive but not definitive data support the idea that one locus may be predominant. Analysis of genetic control of immune responses has been done both in vivo through allograftings and in vitro through mixed lymphocyte culture (MLC) and through responsiveness to mitogens. The axolotl responds to MLC with low but statistically significant stimulation indices and to mitogens in such a way that it is difficult clearly to distinguish between B and T cells. A technique has been developed that leads to failure of thymus differentiation and this may help to clarify the question of lymphocyte cell types inasmuch as thymectomy greatly reduces allograft rejection and permits growth of an allogeneic lymphosarcoma. Evidence is presented suggesting that immune responsiveness is capable of developing at the localized site of immune stimulation rather than requiring movement to foci such as lymph nodes, which are absent in the axolotl. Evidence also is presented that the nature of the allograft can alter the overt expression of the immune response. Lastly, it is shown that while several kinds of neoplasms are seen in older axolotls, these animals tend to respond to allograft challenge more rapidly and more vigorously and thus, for this age group at least, seem to be inconsistent with some theories of aging.