Reaction of human colostral and early milk antibodies with oral streptococci.

Colostrum or early breast milk or both from each of 16 healthy women contained agglutinating antibodies for all normal streptococcal inhabitants of the human oral cavity (S. mutans, S. sanguis, S.

Glutaraldehyde stabilisation of antibody-linked erythrocytes for use in reverse passive and related haemagglutination assays.

A simple method for stabilising antibody-linked red blood cells by the addition of low concentrations of glutaraldehyde is described. Fresh and stabilised reagent-linked cells were shown to compare favourably in reverse passive haemagglutination for the measurement of human immunoglobulin isotypes, G, A and M and for the detection of respiratory syncytial and herpes simplex viruses. Stabilised cells were also used to detect antibodies to bacteria and to a soluble antigen adsorbed to a solid phase by mixed haemagglutination reactions.

The demonstration of sIg, MHC and T cell antigens and Fc receptors on the lymphocyte surface by anti-globulin rosetting reactions: some technical considerations.

The previously shown marked difference in sensitivity of antiglobulin rosette formation and immunofluorescence was confirmed in detection of varying amounts of anti-Ig bound to B cells. The direct and indirect rosette method revealed twice the number of sIg+ cells shown by direct immunofluorescence (DIF), and at least an order of magnitude more antibody on the cell surface is necessary to detect the conventional B cells (shown by DIF) by indirect immunofluorescence compared with indirect antiglobulin (IARR) rosette formation. Variants of the sensitive IARR test were developed to reveal general lymphocyte, MHC class I and class II and T cell-specific antigens and Fc receptors using xenogeneic or allogeneic reagents.

Factors which govern the sensitivity of direct and indirect rosetting reactions and reverse passive haemagglutination in the identification of cell surface and free macromolecules.

A series of immunoassays have recently been elaborated in which the red cell is used as a label or marker of interacting antibody, often anti-immunoglobulin (anti-Ig). This paper considers and investigates quantifiably, the different variables which affect the sensitivity of direct and indirect antiglobulin rosetting reactions (DARR and IARR) and of reverse passive haemagglutination (RPH). Sensitivity is governed by the surface properties and amount of antibody on the indicator red cell and, in detection of cell-bound antigen, by the antigen density.

Measure of rheumatoid factor in human sera by passive haemagglutination of human erythrocytes carrying immunoglobulin linked by chromic chloride.

Serum rheumatoid factor in sero-positive patients with rheumatoid arthritis may be measured by passive haemagglutination of trypsin-treated human red cells linked with heat-aggregated human IgG by chromic chloride. The results show excellent correlation with those obtained with the classical Rose-Waaler test. The sera may be tested unheated and do not require preliminary absorption with red cells.

Comparison of the direct antiglobulin rosetting reaction (DARR) and direct immunofluorescence (DIF) for demonstration of sIg-bearing lymphocytes in pigs, sheep and cattle.

Tests with untreated and trypsin-treated red cells (rbc) from a variety of species showed that anti-Ig-coupled pig RBC are good indicator cells for the study of ruminant blood sIg + lymphocytes by the DARR test; coupled donkey and rabbit RBC are suitable for investigating pig lymphocytes. The different species showed the following percentages of sIg + lymphocytes (M +/- SE) by direct immunofluorescence (DIF) and the direct antiglobulin rosetting reaction (DARR) respectively:pigs 9.2 +/- 0.

Detection of protein A-like substances on haemolytic streptococci prior to use in mixed reverse passive antiglobulin haemagglutination (MRPAH).

Before mixed reverse passive antiglobulin haemagglutination tests (MRPAH) can be used to measure the class of bacterial antibodies, the bacteria have to be shown to be free of Protein A or Protein A-like substances on their surfaces. Two basic procedures have been examined: haemagglutination of red cells coated with immunoglobulin by the bacteria, and the MRPAH reaction itself to reveal absorption of purified gamma Fc by the bacterial suspension. The use of a purified gamma Fc component has proved successful in providing a sensitive test for the detection of Protein A-like substances on the surface of bacterial.

A simplified procedure for measuring the class of anti-bacterial antibodies by mixed reverse passive antiglobulin haemagglutination (MRPAH).

A modified procedure is described for performing the MRPAH (mixed reverse passive antiglobulin haemagglutination) reaction as a simple micro-method to measure the classes of bacterial antibodies. This 'bacterial dilution procedure' gave results closely correlated with those obtained by the 'serum (sample) dilution procedure' previously reported and with great economy of materials, labour and time. The method was used to investigate human serum antibodies to Br.

The class of antibodies sensitizing bacteria measured by mixed reverse passive antiglobulin haemagglutination (MRPAH).

A test is described which is capable of differentiating and measuring by titration the individual classes of antibody reacting with a bacterial suspension. The serum or fluid under test is incubated with the bacteria which are then very well washed and added to indicator red cells linked with specific antiglobulin reagents. Sensitization of the bacteria by a particular class of antibody is shown by haemagglutination (passive) of the appropriate red cells.

Receptors for antibody-opsonic adherence on the eosinophils of guinea pigs.

Eosinophils have recently been implicated in antibody-dependent cell-mediated damage to schistosomula. Because of this, eosinophils of the guinea pig have been examined for surface receptors capable of giving antibody opsonic adherence; a rosetting reaction has been used. The eosinophils were shown to possess Fc receptors for homologous immunoglobulin.

Increased affinity of guinea pig thymocytes and thymus-dependent lymphocytes for papain-treated rabbit erythrocytes compared to untreated erythrocytes.

The affinity of guinea pig thymocytes and peripheral T lymphocytes for rabbit erythrocytes was found to be enhanced following treatment of the erythrocytes with papain. By increasing the numbers of rosette-forming cells and giving stronger, more stable rosettes, this procedure increases the usefulness of the reaction as a T cell marker in guinea pigs.

Observations on rabbit thymocytes and peripheral T cells. II. Rosette formation with rabbit erythrocytes.

The affinity of rabbit thymocytes and a proportion of lymphocytes for homologous and autologous erythrocytes has been investigated. Thymocytes were found to rosette strongly with untreated, washed erythrocytes, although reactions on peripheral lymphocytes from blood and lymph nodes were weaker. Enzyme treatment of the erythrocytes was used in attempts to improve reactions with peripheral lymphocytes.

Observations on rabbit thymocytes and peripheral T cells. I. Anomalous results in the mixed antiglobulin reaction caused by non-specific adsorption of sheep immunoglobulin.

The "single-stage" mixed antiglobulin reaction (MAR) was carried out with rabbit thymocytes. This test involved treating the cells with either sheep or goat anti-rabbit globulin sera, and subsequently reacting them with indicator erythrocytes coated with rabbit immunoglobulin (Ig) so as to form rosettes. An unexpectedly high number (up to 38%) of thymocytes reacted, although the rosettes were weaker than those given by peripheral B lymphocytes.

Immunoglobulin determinants on the lymphocytes of normal rabbits. I. Demonstration by the mixed antiglobulin reaction of determinants recognized by anti-gamma, anti-mu, anti-Fab and anti-allotype sera, anti-As4 and anti-As6.

Immunoglobulin determinants can be shown on the membrane of circulating lymphocytes of the rabbit by the mixed antiglobulin reaction. An enumeration was made of lymphocytes reacting specifically with anti-γ, anti-μ, anti-Fab and anti-L chain sera. The L chain allotypic determinants As4 and As6 were also shown and reacting cells enumerated.