The Role of Enzymes and Albumen in Haemagglutination Reactions

Abstract

In albumen and papain tests, strong haemagglutination showed large areas of cell to cell contact, whereas neuraminidase only caused loose agglutination with small areas of cell to cell contact, confirming a previous suggestion that reduced zeta-potential is not the significant factor in Rh haemagglutination. The ferritin-labelled anti-D was only clustered on neuraminidase- and papain-treated cells, possibly these enzymes cause limited membrane mobility. It is postulated that the loose agglutination in neuraminidase tests is due to localised high density of D sites and that the much greater agglutinating activity in papain tests is due to clustering and protease activity. Increased anti-D antibody uptake is not a critical factor in enzyme tests because cells sensitized and then washed before enzyme treatment were strongly agglutinated. Recent studies have revealed that dextran does not reduce zeta-potential but acts by adsorption between adjacent cells. We suggest that a similar mechanism may explain the action of albumen.

Distribution and Mobility of the A, D and c Antigens on Human Red Cell Membranes: Studies with a Gold‐labelled Antiglobulin Reagent

“…In the present work, A sites on A, red cells have been indirectly visualized using a gold-antiglobulin reagent. The results obtained have confirmed and expanded the results of previous work in which other techniques were uscd (Lee & Fcldman, 1967;Voak & Williams, 1971;Voak et d, 1974). Thus, the present observations show an aggregated pattern of distribution of A sites which contrast with the dispersed distribution of D sites on Rh positive cells.…”

Scanning Electron Microscopy Shows that both Antigen Mobility and Membrane Deformation Occur in the Hemagglutination Reaction

“…The results support the hy pothesis that the red cell membrane antigens exist in a mobile state [9] and that part of the hemagglutination reaction is the forma tion of clusters of these sites [7,11,12], so that bridging between two cells is possible [6], One additional factor involved in the agglutination reaction is the deformation of the red cell membrane [12], which allows the cells to pack more closely and the anti bodies to bridge in a manner not possible with fixed cells.…”

“…The results with the anti-NOVA antiserum, which attaches to the same number of sites as the anti-D serum, were of interest because they show that surface antigen density was not the major factor influencing the aggluti nation reaction [2]. These experiments were consistent with the hypothesis that cluster ing of sites was important for agglutination [7,11,12], no clumping or agglutination of the red cells. Distribution of the antigen was found to be random.…”

“…Though its endpoint, the aggregation of antibodycoated red cells, is easily visualized, the bio physical events are complex [10], Although antigenic mobility has been studied in detail by a number of investigators using techniques such as immunoelectron microscopy [4,12] and varying physiochemical methods of manipulating the agglutination reaction [7], these approaches have not satisfactorily de scribed these events, since in part they yield a two-dimensional picture of a three-dimen sional process. Several developments have made it possible to study the cell surface re action by scanning electron microscopy.…”

Localization and Role of Calcium in the Erythrocyte Coat: Effects of Enzymes and Storage

“…This corresponds to biochemical studies on calcium uptake by erythrocytes which have been partially depleted of sialic acid by treatment with neuraminidase (Long & Mouat, 1971). A similar effect on sialic acid is produced by papain (Voak et al, 1974) and other proteolytic enzymes, e.g. trypsin and pronase (Hubbard & Cohn, 1972).…”