INDUCTION OF IMMUNOLOGICAL TOLERANCE BY INTRACOELOMIC GRAFTS IN THE 4-DAY CHICK EMBRYO

¹ Department of Zoology, University of Maine, Orono, Maine 04473, and U. S. Department of Agriculture. Regional Poultry Research Laboratory, A.R.S., East Lansing, Michigan

1. In a series of experiments in which non-inbred material was used, 9 out of 80 skin grafts from a White Leghorn strain survived more than 20 days on Barred Rock Rhode Island Red hosts which had received intracoelomic grafts of spleen and thymus from older (14- to 21-day) embryos of the same donor strain. Hosts which had received intracoelomic grafts of pharyngeal pouches 3 and 4, limb buds and lens from 4-day embryos, or spleens from 7-, 8-, or 12-day embryos or lens tissue from 15-day embryos, rejected skin grafts from the same donor strain within 20 days.

2. When highly inbred material was used, tolerance was induced in Line 15 I 6 hosts by intracoelomic grafts of limb buds, liver, or pouches 3 and 4 from Line 7 embryos of 4 days. However, a significantly greater degree of tolerance was induced by spleen and thymus tissues from older 9- to 18-day embryos of the same donor strain. The possible impact of near-immunologically competent cells on host cells in the induction of tolerance was considered.