The alkaline phosphatase activity in DBA/2 and A/JAX mouse strains injected with mouse hepatitis virus 3: a morphological and biochemical comparative study.

ALP activity has been studied during hepatitis (infection) in two genetically controlled mouse strains having different degrees of susceptibility ot MHV3 virus: A/JAX (resistant) and DBA/2 (susceptible). During the 8 days following viral infection we have compared ALP activity in serum and liver homogenates with ALP cytological localization in liver tissue (light and electron microscopy). Firstly, liver ALP activity has been demonstrated in the Disse's spaces, on the membrane of the hepatocytes microvilli whilst serum ALP was still very low. The serum ALP activity begins to increase markedly since the third day in sensitive mice (DBA/2), i.e., when the electron microscopy hepatocytes look very damaged; hepatocytes have lost most of their microvilli; necrotic vesicles, degenerative cytoplasmic organelles, lipid vesicles occurred in numerous hepatocytes. ALP activity has disappeared at the biliary pole of the cells whilst it increased at the vascular pole. Moreover, electron microscopic studies demonstrated that ALP positive cells are exclusively of lymphoid type whereas Kupffer cells remain ALP negative.