Sequential changes in the number of surface immunoglobulin-bearing B lymphocytes in infectious bursal disease...

Variations of B lymphocytes bearing surface immunoglobulin (SIg) M [SIg(M)] and G [SIg(G)] were studied in the spleen and peripheral blood of chickens infected with infectious bursal disease virus (IBDV). The proportion of SIg-bearing B lymphocytes and SIg(M)- and SIg(G)-bearing B cells in chickens infected at one day of age decreased from 1 week postinfection (p.i.) onward and was significantly lower at 8 weeks p.i. In chickens infected at 4 weeks, the percentage of SIg-bearing B cells decreased severely during the first 2 weeks p.i. The decrease of SIg(M)-bearing B cells preceded that of SIg (G)-bearing B cells: the lowest percentage of SIg(M)-bearing B cells has observed 2 to 3 days p.i., and that of SIg(G)-bearing B cells was seen 4 days p.i. The results suggest that SIg(M)-bearing B cells are the major target for IBDV infection.