During ontogeny, Ia-bearing accessory cells are found early in the thymus but late in the spleen.
The ontogeny of Ia-bearing accessory cells was studied in mice. Ia-bearing adherent cells from the thymus, consisting predominantly of macrophages, were found from birth. These adherent cells were able to present antigen, as measured by their ability to induce immune T-cell proliferation. In contrast, Ia-bearing adherent cells from the spleen were not found until the second week of life, and their antigen-presentation function was not present until later. The differential ontogeny of Ia-bearing accessory cells at these sites may be important in both development of immune competence and the restriction of autoimmunity.
D000818:Animals; D002448:Cell Adhesion; D007519:Isoantigens / Q000032:analysis*; D008264:Macrophages / Q000276:immunology; D008285:Major Histocompatibility Complex; D051379:Mice; D013154:Spleen / Q000254:growth & development / Q000276:immunology*; D013950:Thymus Gland / Q000254:growth & development / Q000276:immunology*
D007519:Isoantigens