ANTIGEN-SPECIFIC BLASTOGENESIS ASSAYS DUCK HEPATITIS-B VIRUS USING DUCK PERIPHERAL-BLOOD AND SPLENIC MONONUCLEAR-CELLS

An antigen-specific lymphoblastogenesis assay for duck hepatitis B sur face antigen (DHBsAg) and duck hepatitis B core antigen (DHBcAg) was d eveloped using mononuclear cells from the peripheral blood (PBMC) or s pleens (SMC) of immune ducks. Optimal culture conditions for the assay were determined by testing a number of variables, including antigen c oncentration, cell numbers/well, and the day of harvest. The specifici ty of the assay was assessed. The assay used 10% pooled duck serum sup plement, and 8 X 10(5) cells/well for PBMC or 5 X 10(5) cells/well for SMC. The optimum antigen concentration ranged from 0.01 to 0.1 mu g/m l for both DHBsAg and DHBcAg. Maximum antigen-specific blastogenesis o ccurred between 4 to 7 days after establishment of the culture. The us e of PHA (10 mu g/ml) mitogenesis could predict the optimal cell numbe rs/well for antigen-specific blastogenesis. The assay demonstrated spe cific responses by immune ducks compared with those of unexposed duckl ings and adult ducks (for DHBsAg P < 0.001; DHBcAg P < 0.05). For immu ne ducks, PBMC from all 8 ducks responded to DHBsAg, however, cells fr om only 4 of 7 immune ducks responded to DHBcAg. Splenic mononuclear c ells from all immune ducks responded to either DHBsAg or DHBcAg or bot h antigens. (C) 1997 Elsevier Science B.V.