In the routine screening of blood units for hepatitis B surface antigen (HB8Ag)2 and homologous antibody (anti-HB8) by counterimmunoelectrophoresis, we encountered two serum samples which showed precipitin lines both against anti-HB8 and HB8Ag. The HB8Ag in these serum samples were subtyped, and the specificity of co-occurring anti-HB8 was determined, in terms of the d, y, w, and r subspecificities found and described by Le Bouvier (1) and Bancroft et al. (2). HB8Ag/adr plus anti-w were found in one, and HB8Ag/adw plus anti-r in the other.
Both serum samples were obtained from apparently healthy individuals who voluntarily donated a blood unit at regional blood centers in Tochigi-ken and Osaka. They are hereafter referred to as Tog and Osk, respectively. Counterimmunoelectrophoresis was performed in 0.8% J-agar (Sankyo Junyaku Co., Tokyo) dissolved in Veronal buffer (pH 8.6, 0.05 µ). Three wells of 3 mm in diameter were cut in a line 5 mm apart (edge to edge) in an agar plate of 1.2-mm thickness.