Passive hemagglutination assays

When rabbits were immunized with the glycoconjugates suspended in Freund s complete adjuvant antibodies with specificity for the haptenic disaccharides were produced, as estimated in passive hemagglutination and complement-mediated bactericidal tests, and enzyme-linked immunosorbent assay (ELISA) (12-15). 

This procedure is of great potential utility for the identification and enumeration of cells that secrete an antigenic product. Patterned after the assay just described, it employs similar techniques with two major differences The coating for the indicator red cells consists of purified antibody, as in the reverse passive hemagglutination previously described, and an antiserum against the secretion product is used as the developing agent. 

The antibody-coated red cells are prepared as previously described. It is particularly important for this procedure that the indicator red cells are absolutely free of clumps. The sensitivity of coated cells can be assayed by reverse passive hemagglutination if, as in the model under consideration, the antigen is available in soluble form. The cells under study are washed in suitable tissue culture medium or other buffered solution and suspended at a concentration of 10 per milliliter in the same diluent to which serum has been added (usually 1% fetal calf serum). A small volume (50-100 /U.1) of the cell suspension is placed in a 10 x 75 mm disposable tube. The addition of an equal volume of 1% coated red cells results in a mixture that contains about 25 red cells per lymphocyte. Linkage of antibody on the red cells to the corresponding antigen determinant on the surface of the lymphocyte results in the formation of a rosette or lymphocyte surrounded by red cells. The mixing of cells and incubation for at least 1 hr are done in an ice bath. The tubes are then centrifuged very briefly (1 min at 1000 g), and a drop of dye is added to tint the lymphocytes (e.g., crystal violet or brilliant cresyl blue). The mixture is then aspirated four or five times with a Pasteur pipette and examined in a hemacytometer chamber at about 400 x. A cell is scored as a rosette if it is surrounded by three or more adherent erythrocytes, and usually 300 cells are counted. 

Tg antibodies are directed against the Tg protein, a major constituent of thyroid colloid. Several different techniques have been used to detect and quantify TgAb in peripheral blood. These include passive hemagglutination, the agar gel diffusion precipitin technique, immunofluorescence of tissue sections, enzyme-linked immunosorbent assay (ELISA), radioassay techniques, and chemiluminescence-based immunometric assays. 

Serologic assays measuring the immune response to plague infection are mainly of value retrospectively, since patients present clinically before they develop a significant antibody response. Enzyme-linked immunosorbent assay (ELISA) tests and the older, less-sensitive passive hemagglutination as-... 

RAST (radioallergosorbent test) or enzyme assay (IgE, IgG) Histamine liberation from granulocytes Basophil degranulation test Passive hemagglutination Lymphocyte transformation test Macrophage inhibition test Rosette test... 

Immune Responses to Penicillin - The passive hemagglutination system to assay IgG and IgM antibodies of BPO specificity as well as direct skin testing to assay reagins were used. Skin tests were done with benzyl-penicllloylpolylysine (BPL) to detect BPO-speciflc reagins, and a minor determinant mixture (MDM) to detect minor-determinant specific reagins. 

Several methods are available for measurement ofTPO-Ab in serum. Most early studies were done with assays based on immunoflourescence or passive tanned erythrocyte hemagglutination using crude thyroid microsomes as antigen, and the results were reported as positive or negative or as an antibody titer. After identification of TPO as the microsomal antigen, more sensitive methods for detecting TPO-Ab have been established, including RIA, IRMA, ELISA and chemiluminescence methods (Dherbomez... 

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