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R A Childs

Publications and source records attributed to R A Childs.

49 records · Page 3Linked to original sources
PubMed1980

Expression of blood group I and i active carbohydrate sequences on cultured human and animal cell lines assessed by radioimmunoassays with monoclonal cold agglutinins.

Human monoclonal anti-I and anti-i antibodies, reactive with known carbohydrate sequences, have been used as reagents to quantitate (by radioimmunoassay) and visualize (by immunofluorescence) the expression of the various blood group I and i antigenic determinants in a variety of cultured cell lines commonly used in laboratory investigations. It has been shown that the antigens they recognize are widely distributed on the surface of human and animal cell lines, expressed in varying amounts in different cell lines and on individual cells within a given cell line. In two cell lines, a transformation-associated increase in the expression of I antigen was observed. Because of their precise specificity for defined carbohydrate chain domains, these autoantibodies have become valuable reagents in biological chemistry.

Agglutinins↗
PubMed1979

Multiplicity of molecules carrying blood-group-I antigen on erythrocyte membranes.

A human serum containing a monoclonal anti-(blood-group I) antibody was used to investigate the distribution of blood-group-I antigen on erythrocyte membrane components. Sodium dodecyl sulphate/polyacrylamide-gel-electrophoresis profiles of immuneprecipitates by using 3H-labelled (by the galactose oxidase/NaB3H4 method) and 125I-labelled solubilized stroma were compared. Different radioactive profiles were revealed by the two radiolabelling methods. In the immunoprecipitates the predominant 125I radioactivity within the gel had the electrophoretic mobility of Band-3 protein (apparent mol.wt. 90 000--100 000), whereas the 3H radioactivity revealed a diffusely migrating component(s) (apparent mol.wt. range 40 000--70 000) in addition to radioactivity compatible with glycolipids at the dye front. The diffusely migrating 3H-labelled component was shown to have a similar electrophoretic mobility to a subpopulation of erythrocyte poly(glycosyl)ceramides with blood-group-I activity.

Blood Group Antigens↗
PubMed1979

Three types of blood group I specificity among monoclonal anti-I autoantibodies revealed by analogues of a branched erythrocyte glycolipid.

Blood group I activities of the purified glycosphingolipid lacto-N-iso-octaosyl ceramide (Fromula: see text) and 8 of its analogues have been evaluated with 11 anti-I sera including 5 anti-I sera previously tested. All but one of the antisera were inhibited by the lacto-N-iso-octaosyl structure. Three types of I-specificity could be distinguished although none of the anti-I sera was identical in its inhibition patterns with the nine glycophingolipid analogues. The anti-I sera Ma and Woj represent the first type and require an intact Galbeta1 leads to 4GlcNAcbeta1 leads to 6 chain, the anti-I sera Step, Gra, Ver, and Ful represent the second type which requires Galbeta1 leads to 4GlcNAcbeta1 leads to 3 chain with branching, and the anti-I sera Phi, Da, Sch, and Low belong to the third type which requires both branches to be intact. Anti-I antibodies varry in their ability to react with their antigenic determinants in the presence of external substitutions with alpha-linked galactose or sialic acid.

Antibody Specificity↗
PubMed1978

Blood-group-Ii-active gangliosides of human erythrocyte membranes.

More than ten new types of gangliosides, in addition to haematoside and sialosylparagloboside, were isolated from human erythrocyte membranes. These were separated by successive chromatographies on DEAE-Sephadex, on porous silica-gel columns and on thin-layer silica gel as acetylated compounds. Highly potent blood-group-Ii and moderate blood-group-H activities were demonstrated in some of the ganglioside fractions. The gangliosides incorporated into cholesterol/phosphatidylcholine liposomes stoicheiometrically inhibited binding of anti-(blood-group I and i) antibodies to a radioiodinated blood-group-Ii-active glycoprotein. The fraction with the highest blood-group-I-activity, I(g) fraction, behaved like sialosyl-deca- to -dodeca-glycosylceramides on t.l.c. Certain blood-group-I and most of the -i determinants were in partially or completely cryptic form and could be unmasked by sialidase treatment. Thus the I and i antigens, which are known to occur on internal structures of blood-group-ABH-active glycoproteins in secretions, also occur in the interior of the carbohydrate chains of erythrocyte gangliosides.

Blood Group Antigens↗
PubMedDate not supplied

Erythrocyte receptors for Mycoplasma pneumoniae are sialylated oligosaccharides of Ii antigen type.

Among the pathological effects in man following infection with Mycoplasma pneumoniae is a transient autoimmune disorder characterized by the presence of high-titre erythrocyte autoantibodies (cold agglutinins). These autoantibodies are usually directed against the carbohydrate antigen termed I (ref. 3) which consists of a branched oligosaccharide. The mechanism by which the anti-I antibodies are elicited is unknown. However, sialic acid-containing receptors have been implicated in the adherence of M. pneumoniae to erythrocytes and other cell types, and both I and the related antigen i occur on erythrocytes in sialylated form: i is the predominant antigen on fetal erythrocytes and I is predominant in adults. Anti-I antibodies might arise in M. pneumoniae infection in response to a modification of the 'self' antigen-I as a result of its interaction with this agent. Here we report our study of the specificity of the interaction of M. pneumoniae with human erythrocytes. We found that this interaction is mediated by long chain oligosaccharides of sialic acid joined by alpha 2-3 linkage to the terminal galactose residues of poly-N-acetyllactosamine sequences of Ii antigen type.

Anion Exchange Protein 1, Erythrocyte↗