Immune capacity of the chicken bursectomized at 60 H of incubation. Effect of bursal epithelial cells and bursal epithelium-conditioned medium on the production of immunoglobulins and specific antibodies in vitro.

Cells from chickens bursectomized at 60 h of incubation (Bx) are known to produce immunoglobulins without any detectable antibody specificity. In the present work cells from Bx birds were cultured together with bursal epithelial cells (BE) or bursal epithelium-conditioned medium (BECM) to establish whether they could be induced to produce specific antibodies. Cells obtained from 10-day-old or 10-week-old birds were used. The effects were assessed with regard to the production of total immunoglobulins and specific antibodies; the birds had been preimmunized. BE had no effect on the production of immunoglobulins by either Bx or control (Co) cells. When cells from 10-week-old birds were cultured in the presence of BECM, no difference in the immunoglobulin production was seen between Bx and Co chicken cells. At the age of 10 days the cells of Bx birds produced considerably less Ig than the cells of normal Co birds. At this age BECM had no effect on the Co cells, but it markedly enhanced the production of IgA-class immunoglobulins of Bx birds. With regard to production of specific anti-tetanus antibodies, BE stimulated the production of IgA-class antibodies by cells from preimmunized Co chickens but had no effect on cells from preimmunized Bx birds. In spite of the normal production of immunoglobulins in vitro the cells of Bx chickens did not produce specific antibodies. In conclusion, these findings indicate that if B cells have matured without a contact with the bursa of Fabricius, later in vitro exposure to BE or BECM can no longer induce them to production of specific antibodies.