Hemagglutination and hemagglutination inhibition tests of rubella virus

Abstract

Methods of rubella virus hemagglutination (HA) and hemagglutination inhibition (HI) tests reported by Stewart et al are highly sensitive and reproducible, and it has remarkably promoted the development of the studies of rubella virus.In this study, precise investigations on the techniques of rubella, virus HA and HI tests were performed by a tube method based on their report, and it was found that special cares should be taken to the elimination of inhibitor which was contained in human serum and showed considerably high HI titer compared with the one of rubella antibody.The results obtained were described in this report.1) Erythrocytes of geese, Japanese quails, chikens (1-, 2-, 5-, 7- and 15-day old) and adult chickens were tested for their sensitivities to HA. The use of erythrocytes from geese, Japanese quails and 1-, 2- and 15-day old chickens resulted in high HA titers, but cells from 7- and 15-day old chickens and adult chickens gave remarkably low HA titers.2) Optimal pH range in HA test is 6.0 to 6.4 for all species of cells showing high HA titer. By using DGV buffer of pH 6.3, clear pattern of hemagglutination is observed.3) Inhibitor of rubella virus hemagglutinin in human sera looks unquestionably like B-lipoprotein and gives high HI titer such as 1024 to 4096 folds in many samples and 512 or 8192 folds in some. Inhibitor in sera from hyperlipoproteinemia was also determined and HI titers of 8192 folds or more were detected in many cases. HI titer of inhibitor and content of B-lipoprotein in serum corelate fairly well.4) Inhibor adsorbing capacity of kaolin differs remarkably by each product. A 0.15 g of acid washed kaolin of Fisher Co. per 0.2 ml of serum was confirmed to be an adequate volume to eliminate the inhibitor completely without any loss of antibody, however it seems that. there might be batches, even though of Fisher's product, which showed a less capacity of adsorption.5) Inhibitor adsorbing capacity of kaolin becomes lower at low pH when it is suspended in DGV buffer. Lowering of capacity is attributable to gelatin contained in the buffer.6) Although the technique of aceton extraction is fairly complicated, the removal of inhibitor is complete and no loss of antibody is resulted.7) Heparin-manganous chloride treatment also gives a complete elimination of inhibitor without any loss of antibody. Twenty units of heparin per 0.1 ml of serum give an incomplete elimination and it is necessary to use more than 40 units for a complete elimination.8) Dextran sulfate-calcium chloride treatment also gives a complete elimination of inhibitor without remarkable losses of antibody and is an excellent method in respect of its simplicity and rapidity.