Localization of factor VIIIC: antigen in guinea‐pig tissues and isolated liver cell fractions

Factor VIIIC:antigen (VIII:CAg) was estimated in guinea-pig tissues by an immunoradiometric assay using a human inhibitor antibody. In homogenized guinea-pig tissues, VIII:CAg was shown to be stable and to be predominantly located in the liver (9 +/- 1.2 units; mean +/- SEM, n = 8). Lesser amounts were detected in spleen (1.3 +/- 0.02 units), lung (0.6 +/- 0.07) and kidney (0.4 +/- 0.06). In isolated liver cell fractions separated by centrifugal elutriation VIII:CAg was mainly detected in the hepatocyte fraction (0.3 +/- 0.07 units/10(8) cells;mean +/- SEM, n = 5) and in lesser amounts in the endothelial (0.02 +/- 0.01 units/10(8) cells) and the Kupffer cell fractions (0.05 +/- 0.02 units/10(8) cells). The liver concentration of VIII:CAg was (0.17 +/- 0.02 units/g) which was 20% of the plasma concentration (0.96 +/- 0.01 units/ml, n = 8) suggesting that VIII:CAg may not be stored in the liver but is rapidly exported following synthesis.