Immunoglobulin diversification in bursal duct-ligated chickens

The role of external antigen contact on immunoglobulin (Ig) diversification occurring in chicken bursal cells was evaluated. The entry of environmental antigens into the lumen of the bursa of Fabricius was prevented by ligating the bursal duct prior to hatching (BDL: bursal duct ligation). We used two-dimensional gel electrophoresis to compare the heterogeneity of Ig molecules from bursa cells of normal and BDL chickens. We have found that Ig diversity obtained from BDL chickens' bursae in two-dimensional gel analysis was similar to that of control birds. Furthermore, by using two monoclonal anti-idiotype antibodies to study intrabursal Ig diversification we have shown that frequencies of the Cld-1 and Cld-2 idiotypes were also unaltered following bursal ligation. We conclude that primary B cell diversification in the bursa is independent of the external antigen flow from the bursal lumen.