Research interests:

My current research interest is the evolutionary foundations of specific recognition in the animal immune system. I study allogeneic histoincompatibility in the marine sponges, Callyspongia diffusa and Microciona prolifera. I discovered acute rejection reactions initiated within 1 to 2 hours of contact with non self cells and involving the vigorous participation of gray cells, candidates for the immunocytes of sponges. To interpret these results, I have postulated that invertebrate immunocytes have receptirs which specifically recognize self markers and that the immunocytes reject all cells that do not display the specific self markers. I think that the self receptors and self markers are the evolutionary precursors of, respectively, the T-cell receptor and the major histocompatibility marker proteins. I am engaged in molecular studies to characterize these molecules on sponge cells.

Hemichordate, click image to see larger version

Recent Publications:

• Humphreys, T. and Reinherz, E. L. 1994. Invertebrate immune recognition, natural immunity and the evolution of positive selection. Immunol. Today 15: 316-320
• Humphreys, T. 1994. Rapid allogeneic recognition in the marine sponge Microciona prolifera. Ann. N. Y. Acad. Sci. 712: 342-345
• Yin, C., and Humphreys, T. 1996. Acute cytotoxic allogeneic histoincompatibility reactions involving gray cells in the marine sponge, Callyspongia diffusa. Biol. Bull. 191: in press.

htom@hawaii.edu