Direct observation of immunoglobulins on the erythrocyte membrane.

A modification of the sublimation procedure for observation of cell membrane exteriors is described. By retaining basic advantages of the freeze-fracture technique, without actual fracturing of the sample, high quality replicas can be produced on which molecules such as immunoglobulins can be identified and mapped on extensive areas of the erythrocyte membrane surfaces. The method can be used for direct observation of antibodies without recourse to labelling with other marker molecules, such as for example ferritin.

Distribution and mobility of the A, D and c antigens on human red cell membranes: studies with a gold-labelled antiglobulin reagent.

Studies are presented in which a gold-labelled anti-IgG reagent has been used to map the distribution of A, D and c antigen sites on the human red cell membrane. Red cells were combined with IgG antibodies; ghosts were produced which were then labelled with gold-anti-IgG. D antigen sites were found to be single entities dispersed on the red cell membrane of lysed but otherwise untreated Rh positive cells.

Red cell destruction in vivo by low concentrations of IgG anti-A.

Red cells coated with as little as 0.3-0.5 mug anti-A/ML cells were found to agglutinate if mixed with plasma and rocked on a tile, whereas the minimum amount of IgG anti-Rh required for agglutination under these conditions was about 50 mug antibody/ml cells.

Direct antiglobulin reaction in ABO-haemolytic disease of the newborn.

The minimum number of IgG anti-A (or anti-B) molecules detectable on A or B red cells by the antiglobulin reaction was found to be the same-that is, about 150 molecules per red cell-with newborn as with adult cells. Furthermore, the ratio of anti-IgG bound to IgG anti-A (or anti-B) molecules was the same whether the anti-A (or anti-B) molecules were present on newborn or on adult cells and was similar to that found for anti-IgG bound to IgG anti-Rh.In 15 infants (11 group A, 4 group B) with haemolytic disease of the newborn due to ABO-incompatibility the amount of anti-A or anti-B on the red cells ranged from 0.