[The screening of hepatitis virus and its efficacy].

1. Infection of hepatitis A virus (HAV) was prevented with hepatitis A vaccine. High risk groups of HAV infection should be inoculated this vaccine because Japanese peoples less than 40 years old didn't have immunity for HAV. 2. Infection of hepatitis E virus (HEV) was scarcely observed in Japan. 3. Infection of hepatitis B virus (HBV) by blood transfusion was eradicated after the screening with anti-HBc antibody for blood donors. And maternal transmissions of HBV and infections of HBV in hospital were protected by HB-globulin and hepatitis B vaccine. 4. Infection of hepatitis D virus (HDV) was protected by HB-globulin and hepatitis B vaccine. 5. Infection of hepatitis C virus (HCV) by blood transfusion markedly decreased after the screening with anti-HCV for blood donors. We can't prevent a maternal transmission of HCV but its frequency is low (about 10%). And acute hepatitis C due to an infection of HCV in hospital can be prevented by the treatment with interferon in the Workmen's Accident Compensation Insurance.

Quantitative analysis of Lewis antigens on erythrocytes by flow cytometry.

We have developed a method for the quantitative analysis of Lewis antigens on human red blood cells (RBC) using immunofluorescence labeling and flow cytometry. Initially, Lewis a and Lewis b (Le(a) and Le(b)) antigens were labeled with monoclonal anti-Le(a) or anti-Le(b) antibodies followed by labeling with the fluorescein isothiocyanate (FITC)-conjugated second antibody. This method was not sensitive enough to identify the Lewis antigens on RBC, although the FITC method is very commonly used for antigens on white blood cells. Next, we selected the enhanced labeling technique using the avidin-biotin procedure. Biotinylated anti-mouse IgM was used for the second label and the reaction with R-phycoerythrin (RPE)-conjugated streptavidin followed to produce the fluorescence. The method was found to be effective for our objectives. From the results analyzed by the enhanced labeling technique, differences were not found in either the levels of the antigen-positive percentage and the peak mean channel of Le(a) antigens on RBC in the groups of blood type O and A (in ABO system). On the other hand, both the levels of Le(b) antigens on RBC were higher in the groups of blood type O than in those of blood type A. We found both Le(a) and Le(b) antigens on RBC from a few blood type O subjects. We conclude that enhanced labeling and flow cytometry constitute a useful technique for the determination of Lewis antigens on RBC and that this method enables the precise quantification of such antigens.