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R Dalchau

Publications and source records attributed to R Dalchau.

27 records · Page 2Linked to original sources
PubMed1982

The gene, MIC4, which controls expression of the antigen defined by monoclonal antibody F10.44.2, is on human chromosome 11.

The monoclonal antibody, F10.44.2, is directed against a human antigenic determinant of restricted tissue distribution. In this report it is shown that this determinant is coded for by a gene, MIC4, which is on human chromosome 11, as shown by its reactivity with a panel of somatic cell hybrids. Synteny with an antigen recognized by another monoclonal antibody, W6/34, is demonstrated by hybrid and fluorescence-activated cell sorter analysis, although it is clear from absorption analysis that the determinants involved are on different molecules.

Animals↗
PubMed1982

Biochemical characterisation and localization in brain of a human brain-leucocyte membrane glycoprotein recognised by a monoclonal antibody.

The F10-44-2 monoclonal antibody was originally shown to interact with a determinant found predominantly in human brain and leucocytes. In this study we demonstrate by quantitative absorption analysis with homogenates of the head of the caudate nucleus, putamen, thalamus, cerebral grey matter, cerebral white matter, corpus callosum and cerebellar folia that the determinant is restricted to the white matter of the CNS. Immunofluorescence studies on frozen sections of the above brain subregions confirm the absorption analyses, showing staining only of white matter. In addition, and unexpectedly, we found very bright staining around blood vessels, particularly in the cerebellum. Biochemical studies established that the molecule in white matter bearing the F10-44-2 determinants is a sialylated membrane glycoprotein with an apparent molecular weight of 90,000, which is similar to but slightly smaller than the T lymphocyte form of the antigen. Developmental studies comparing 16-week foetal and adult cerebrum showed a fivefold increase in F10-44-2 antigen content. Thus, in the human CNS, the F10-44-2 antigen is a medium-sized glycoprotein which is restricted to white matter and shows a marked increase in concentration during development. No such molecule has been described previously.

Antibodies, Monoclonal↗
PubMed1981

Identification with a monoclonal antibody of a predominantly B lymphocyte-specific determinant of the human leukocyte common antigen. Evidence for structural and possible functional diversity of the human leukocyte common molecule.

Initial studies with the monoclonal antibody F8-11-13 described in this paper showed that it reacted strongly with B lymphocytes, did not react at all with granulocytes, and reacted only weakly with a small subpopulation of thymocytes and peripheral T lymphocytes. This picture was entirely different from that seen with monoclonal antibodies to the leukocyte common (LC) antigen, where 100% of all the above-mentioned leukocyte populations were positive. Biochemical studies using detergent solubilized membranes labeled with 3H at the sialic acid residues showed that the molecule bearing the F8-11-13 determinant was a glycoprotein of 215,000 mol wt, and that the peak depleted by F8-11-13 monoclonal antibody affinity columns corresponded to the high molecular weight region of a broad peak previously shown to be completely depleted by monoclonal antibody (F10-89-4) affinity columns directed at the LC antigen. Proof that the F8-11-13 determinant was expressed on some LC molecules was established by cross-inhibition studies with affinity-column-purified and depleted material. This finding of a serologically identifiable conformational or other structural change selectively expressed on the LC molecule of a functionally discrete population of lymphocytes has interesting implications for the structure and function of the LC molecule, and might be relevant to functional consideration of other membrane molecules.

Animals↗
PubMed1980

Monoclonal antibody to a human leukocyte-specific membrane glycoprotein probably homologous to the leukocyte-common (L-C) antigen of the rat.

The monoclonal antibody (F 10-89-4) described in this study recognizes an antigen which by quantitative absorption analysis is absent from human brain, kidney, liver, heart, erythrocytes, platelets and normal serum, but is present on spleen, lymph node, chronic lymphatic leukemia cells, bone marrow, thymus and granulocytes at a ratio of 1:1:0.8:0.3:0.1, respectively. Analysis with the fluorescence-activated cell sorter showed that 100% of thymocytes, lymph node lymphocytes, blood mononuclear cells and granulocytes carry the antigen, while 83% of bone marrow cells are positive. There was marked heterogeneity in the amount of labeling of thymocytes, with 3 major peaks. There was also heterogeneity of labeling of blood mononuclear cells and lymph node lymphocytes, with a weakly staining hump containing approximately 20% of the cells in the case of lymph node lymphocytes. Double labeling experiments demonstrated that the weakly staining cells of blood and lymph node were B lymphocytes, while frozen sections of thymus showed that the antigen was expressed most weakly in subcapsular cortical thymocytes, and most strongly on medullary thymocytes. Biochemical studies established that the antigen bound to lentil lectin columns, and sodium dodecyl sulfate polyacrylamide gel electrophoresis studies using NaB3H4-labeled blood mononuclear cells established that the antigen was a major glycoprotein of lymphocytes, and that its molecular weight was in the region of 190000 to 215000.

Absorption↗
PubMed1980

Monoclonal antibody to a human brain-granulocyte-T lymphocyte antigen probably homologous to the W 3/13 antigen of the rat.

The monoclonal antibody (F 10-44-2) described in this report recognizes an antigen which by quantitative absorption analysis is found predominantly on spleen, lymph node, bone marrow, thymus, granulocytes and brain, the amount of antigen on these tissues being approximately the same within a factor of 2 or 3. Analysis with the fluorescence-activated cell sorter showed that 29% of thymus cells, 61% of bone marrow cells, 95% of blood mononuclear cells, 98% of lymph node lymphocytes and 100% of granulocytes carried the antigen. With blood mononuclear cells and lymph node lymphocytes, there were two distinct peaks, with one peak labeling very weakly. Double labeling experiments established that the weakly labeled peak contained the B lymphocytes. Studies on frozen sections of thymus established that positive thymocytes were found only in the medulla indicating that the antigen appears late in T lymphocyte maturation. The lymphatic nodules (B lymphocyte areas) of spleen and lymph node appeared virtually negative on frozen sections showing that there was too little antigen on the B lymphocyte surface for confident detection by fluorescence microscopy. Sodium dodecyl sulfate polyacrylamide gel eletrophoresis of NaB3H4-labeled blood mononuclear cells established that the antigen was a major glycoprotein of the leukocyte membrane and that its mol. wt. was 105000. This antigen shows a striking similarity in biochemistry and tissue distribution to the W 3/13 antigen of the rat and is likely to be the human homologue of this antigen.

Absorption↗
PubMed1980

Quantitative studies of the tissue distribution of the antigens recognized by rabbit anti-rat, -dog and -human lymphocyte sera.

Rabbit anti-rat, -dog and -human ALS was analysed using quantitative absorptions and indirect 125I anti-immunoglobulin-binding assays to determine the amount of antibody directed against different types of antigen. The aim was (a) to determine what proportion of the antibodies was directed against leucocyte-specific antigens and (b) to see if the type of leucocyte-specific antigen recognized varied either with the species or the cell type used as the immunogen. The results showed that anti-thymocyte sera in all three species showed the same high degree of leucocyte specificity. Marked differences in the type of leucocyte-specific antigen recognized were found when anti-thymocyte and anti-lymph node lymphocyte sera were compared. A comparison of the leucocyte-specific antigens recognized by anti-dog and -human thymocyte sera showed quantitative but not qualitative differences. The relevance of these results to the current failure of ALS in clinical practice and to the problems of ALS standardization are discussed.

Animals↗
PubMed1979

Identification and unusual tissue distribution of the canine and human homologues of Thy-1 (theta).

The tissue distribution of the canine and human homologues of Thy-1 were studied using quantitative absorption analyses of liver absorbed anti-brain xenosera assayed on thymus cells. Cross-reactivity studies with pure rat Thy-1 established that the assays were detecting the homologues of rat Thy-1. The results showed that the tissue distribution of Thy-1 varies remarkably between species. Canine Thy-1 was found in large amounts only on adult brain. It was present in much smaller amounts on thymus (8% compared with brain), and was also found on lymph node, spleen and bone marrow (3, 1 and 0.5%, respectively, compared with brain). Surprisingly, it was found on kidney in amounts equal to that on thymus. Studies with the fluorescence-activated cell sorter established that canine Thy-1 was present on all thymocytes and peripheral T lymphocytes. Neonatal thymus and kidney had adult levels of Thy-1, but only small amounts of Thy-1 were present on neonatal brain. In man, brain was again the only tissue to contain large amounts of Thy-1. Surprisingly, it was absent from human thymus, and present on human kidney in amounts roughly equivalent to that seen in the dog. It was absent from spleen, lymph node, bone marrow, liver, heart, erythrocytes, platelets, and serum. Cross-reactivity studies showed that dog and human Thy-1 showed extensive serological cross-reaction, and that the dog-rat and human-rat cross-reactive components were identical.

Animals↗
PubMed1979

Tissue distribution of brain-thymus shared antigens recognized by anti-brain xenosera in the rat, dog and man.

A comparative and quantitative study of the tissue distribution of brain-thymus shared antigens was carried out using rabbit antisera to rat, dog and human brain homogenates, assayed on rat, dog and human thymus cells, respectively. Quantitative absorption analyses with eleven different tissues showed that the tissue distribution of the brain-thymus antigens was strikingly different in the three species. In the rat, the antigens were present in large amounts on both brain and thymus, to a lesser extent on bone marrow cells, but not at all, or only slightly, on the other tissues studied. In the dog, the shared antigens were present in large amounts only on brain. They were present in smaller amounts (approximately 5% compared with brain) on thymus, spleen, lymph node and, unexpectedly, kidney, and to a slight extent on bone marrow cells. In both rat and dog, absorption to a plateau with liver indicated the presence of brain-thymus shared antigens of restricted tissue distribution. No brain-thymus antigens of restricted tissue distribution could be detected in man, since liver, heart, kidney, brain and all other tissue studied, excepting erythrocytes and platelets, could absorb out all the antibody.

Animals↗