Role of the Bursa of Fabricius in IgG and IgM Production in the Chicken: Evidence for the Role of a Non-Bursal Site in the Development of Humoral Immunity
Ablation of the bursa of Fabricius in the chicken at different times and by different techniques was carried out to assess the relative effects on production of antibodies to SRBC and of IgM and IgG. In confirmation of previous work, IgG and IgG antibody production were readily inhibited by bursectomy. In contrast, IgM production was increased by the methods used unless irradiation was added. Dipping eggs in testosterone propionate at 3 days of incubation, which completely prevented development of the bursa, resulted in IgM levels at 14 wk that were 4 × those of controls but not accompanied by any increase in the level of IgM anti-SRBC. The results indicate that: 1) the bursa has a major role in the maturation from IgM to IgG synthesis, and 2) the bursa is not essential for antibody and immunoglobulin production.