| Abstrakt: |
The immunological competence of blood of White Leghorn chicken donors, as measured with the “graft-versus-host” reaction (GVHR), increased rapidly in the first 3 weeks, then at a slower rate reached a plateau level at about the 12th week of age. A comparable age-related elevation in the GVHR level of blood was observed in Game chicken donors, but the magnitude of the host embryo splenomegaly was much greater and the plateau level was attained by the 16th week of age. The age profiles of individual donors and the WL-2 donors as a group indicate that the competence of blood does not rise steadily with increasing age but fluctuates considerably. During the ages of 1-12 weeks, elevated levels of competence occurred frequently at the 3rd, 6th, and 12th weeks, and depressed levels, at the 4th and 8-9th weeks of age. The increase with age in the GVHR capacity was correlated with a corresponding change in mononuclear cell concentration of donor blood. Similar variations in immune competence were observed in the spleen and thymus. The variable nature of alloimmune responsiveness is attributable to fluctuations in the level of competent cells in blood and other tissues. A rapid maturation of the immunological capacity during the first few weeks is inferred from the elevation in the GVHR capacity despite an increase in body size at this time. A less rapid elevation and subsequent maintenance of a “plateau level” during the 4- to 22-week period indicate that the growth more nearly parallels that of body growth. |
