Enhancement of Growth of Chick Host Spleens following Chorio-allantoic Membrane Grafts of Homologous Tissues1

Abstract

The phenomenon of enlargement of the host chick embryo spleen, following grafts of homologous adult chicken tissues to the chorio-allantoic membrane (CAM), affords the investigator an excellent tool for the study of growth. Initial observations of this phenomenon were made by Danchakoff (1916) and Murphy (1916). Grafts of adult chicken spleen on the chorio-allantoic membrane of 9-day-old chick embryos brought about a striking enlargement of the host spleens after 8 additional days of incubation. The phenomenon was later studied by Ebert (1951), who showed that the effect was only partially organ-specific. Grafts of thymus and liver affected the weight of the host spleen, but in each case the effect was far smaller than that observed with splenic transplants. Andres (1955) found that injected kidney and liver debris, which elicited an increased mitotic index in the homologous host organ, was not inhibited in its action by killing the cells through freezing and subsequent thawing.

Donor-Host Cell Interaction in Homologous Splenomegaly in the Chick Embryo

“…The host spleens were removed on the 17th or 18th day of incubation and weighed to the nearest 0.2 mg. The graft on the CAM was graded according to the degree of incorporation and vascularization (Mun, Kosin and Sato, 1959). The embrvo was drained, blotted on paper, and weighed to the nearest 0.1 gram.…”

“…Whether the proliferation of host cells was necessary in this phenomenon may be ascertained by exploring the consequences of their inactivation or elimination. Mun, Kosin and Sato (1959) have previously studied the effects of inactivation of adult chicken spleen tissue by x-irradiation. \Yith increasing dosage of x-irradiation the ability of the donor tissue to elicit splenomegaly was gradually diminished.…”

An Analysis of the Initial Reaction in the Sequence Resulting in Homologous Splenomegaly in the Chick Embryo

“…At least a tentative answer to this question is obtained by the use of embryos from two inbred lines of chicks. Mun, Kosin and Sato (1959), using two inbred lines of chickens, found that a greater splenomegaly was obtained when the donor tissue was derived from an adult chicken of the opposite line than from the same line. Cock and Simonsen (1958) made similar observations using injection techniques.…”

“…ated homologous spleen cells and cells x-irradiated at low doses caused approximately six-fold enlargement of the embryo spleen, yet cells irradiated with moderate doses had little or no effect. Other treatments, e.g., boiling, and freezing and thawing, also remove all activity (Mun, Kosin and Sato, 1959).…”

“…The reaction is class-specific ; grafts of spleen of other avian species, such as duck, turkey, and pheasant, produce some effect but never as much as homologous spleen ; rat, mouse and guinea pig spleens are completely ineffective in the chick (Ebert, 1951(Ebert, , 1954Mun, Kosin and Sato, 1959). Presumably, the ineffectiveness of mammalian cells is a consequence of their failure to survive the rigors of the foreign environment long enough to produce an immune response.…”