Ontogenetic Studies on Lymphoid Cell Traffic in the Chicken

Abstract

Male chickens of different ages were injected with tritiated thymidine into the parenchyma of the thymus and the transport of thymic label and of thymus-derived cells to other lymphoid organs was studied. Using a radiochemical method based on DNA and tritium measurements in different organs, a quantitatively significant transport of label from the thymus to the spleen, the caecal tonsils, and to the bone marrow could be demonstrated in the 9-day-old chicken. The transport to the spleen was shown to continue in the 6-week-old and 14-week-old animal. Autoradiographically, thymus-derived cells could be found in the spleen and caecal tonsils as early as in the newly hatched period. Autoradiographic data also indicated that the traffic increased up to 6 weeks of age but decreased in older animals. In the 6-week-old group, the localization of the thymus-derived cells in the target organs was determined. Such cells in the spleen were distributed almost equally between the red and white pulp. Very few of the thymus-derived cells were highly pyroninophilic. None could be found in the germinal centres. No sign of cell transport from the thymus to the bursa of Fabricius could be detected. The pattern of cell migration is well correlated to the morphological and functional maturation of the lymphoid system.

Migration of Bone Marrow Cells to the Bursa of Fabricius and the Spleen in the Chicken

“…With the present technique we have earlier demonstrated that newly formed cells do not migrate from the bursa (6,13) or from the thymus (4,14) to pre-existing germinal centres. In the present study we have been unable to find bone marrow-derived h.l.c.…”

The effect of embryonic bursectomy on the rosette‐forming cells in the chicken

“…It is possible that the RFC differentiate in the bursa1 microenvironment, as large numbers of antigenbinding cells have been demonstrated in the embryonic bursa [ 171 and significant numbers of anti-SRBC RFC are present in the adult bursa (Back, R., personal communication). Furthermore, it has been shown that there is a migration of lymphoid cells from the bursa of Fabricius t o other lymphoid organs, including the thymus, in the chicken embryo [ 181 and the young chicken [19]. It is possible that some of these cells or their precursors are RFC.…”

Cellular composition of the bone marrow in the chicken: II. The effect of age and the influence of the bursa of fabricius on the size of cellular compartments

“…Evidence has been presented for the existence of T cells in chicken marrow (Lydyard and Ivanyi, 1971;Kirchner and Blaese, 1973) and also against it (Hudson and Roitt, 1973). Following the local injection of 3H-TdR into the bursa of normal chicks, direct migration of lymphocytes to the marrow could not be demonstrated (Hemmingsson and Linna, 1972;Hemmingsson, 1972), whereas other studies suggest such a migration stream . Chromosomal marker studies have also revealed the migration of bursal cells to marrow (Weber, 1972).…”

“…The present studies do not address either of these questions. Despite attempts to label locally with 3H-TdR the chicken thymus (Hemmingsson, 1972), or chicken marrow , it is not possible to speculate on these issues without further experiments. Evidence has been presented for the existence of T cells in chicken marrow (Lydyard and Ivanyi, 1971;Kirchner and Blaese, 1973) and also against it (Hudson and Roitt, 1973).…”