The hypothesis was that the cellular architecture of the lymphoid tissue was determined by antigenic stimulation. In order to test that hypothesis chickens were produced and maintained in an environment as free from antigens as possible. The chickens were then challenged with an antigen and the cellular changes in the lymphoid tissue, especially the spleen, examined. The thesis thus falls into three sections. In Section 1, after the concept of germ-free life was introduced, the practical problems of producing and maintaining germ-free chickens were discussed in relation to the needs of the present work. A detailed description then followed of the method by which germ-free chickens were produced and maintained in this study. The use of the germicide "Portex D.C.R." was described for sterllizing the surface fertile a eggs in order to obtain germ-free chickens. In Section II the lymphoid tissue of the conventional chickens was described. In order to form bose-line or norm for the study of the effect of antigens in germ-free chickens the lymphoid tissue of the four weeks old unstimulated germ-free chicken was stufied. Serum proteins from these birds were immuncelectrophoresed. It was shown that in the unstimulated four week old germ-free chicken no germinal centres were present in the spleen and that there were fewer cells of the plasmacellular series when compared with four week old conventional chickens. The level of immune-globulins was lower in germ-free chickens than in conventional chickens. Having established this norm it was then possible (Section III) to challenge the germ-free chickens with an antigen in an attempt to induce germinal centre formation and study the way in which germinal centres were formed. The tissues from the germ-free chickens stimulated with a known antigen were examined using conventional histology and immunofluorescence; serum antibodies were estimated and serum proteins were immunoelectrophoresed. In experiment I an attempt was made to induce germinal centre formation in conventional birds using Shigella glexneri as antigen. In the next two experiments a soluble protein antigen (Human serum albumin) was administered to seven day old germ-free chickens (expt. 2) and to seven day old conventional chickens (expt. 3) to induce germinal centre formation. In the remaining three experiments a staphylococcus isolated from a chickens was used as antigen. Germ-free chickens were given the staphylococcus as a primary injection at seven days old (expt. 4) and at twenty-one days old (expt. 5) and as a secondary injection at twenty-one days old (expt. 6) following a primary at seven days old. From there experiments it was concluded that the cellular architecture of the same age was not the same. In germ-free chickens both the soluble protein antigens (HSA) and the particulate antigen (staphylococcus) induced proliferation of cells of the plasmacellular series but germinal centres were found in the spleen following stirculation with staphylococcus. Further, the response to the same dose of the same antigen (staphylococcus) varied with the age of the chicken during the neonatal period. A greater number of germinal centres and a greater proliferation of cells of the plasmacellular series was induced following injection of staphylococcus into 21 day old germ-free chickens than into 7 day old germ-free chickens. A secondary challenge with staphylococcus at 21 days old in germ-free chickens following a primary injection at 7 days old induced a greater number of germinal centres than a primary injection at 21 days old. The germinal centre appeared to be formed in the spleen not by rapid multiplication of a small focus of cells but by aggregation of haemocytoblasts in the periarteriolar lymphocyte sheath. Lymphocyres did not appear to be incorporated in germinal centre formation but seemed to be formed from haemocytoblasts within the germinal centre. No cellular changes were induced in the thymus or bursa of Fabricius following antigenic stimulation of germ-free chickens. It was clear from the experimental work that the cellular architecture of the spleen of the chicken was dependent upon immunogenic stimulus.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:768652 |
| Date | January 1970 |
| Creators | Anderson, James Currie |
| Publisher | University of Glasgow |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://theses.gla.ac.uk/40960/ |
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