Biomedical subjects

R Stauder

Publications and source records attributed to R Stauder.

22 records · Page 2Linked to original sources

PubMed1989

Expression of leucocyte function-associated antigen-1 and 7F7-antigen, an adhesion molecule related to intercellular adhesion molecule-1 (ICAM-1) in non-Hodgkin lymphomas and leukaemias: possible influence on growth pattern and leukaemic behaviour.

In 160 non-Hodgkin lymphomas (NHL) of B and T cell origin the expression of leucocyte function-associated antigen-1 (LFA-1) and one of its counter-structures named 7F7-antigen was studied. Functional and structural similarities and the 7F7-reactivity of pICAM-1 transfected COS-cells prove that 7F7-antigen is identical with ICAM-1. The expression of both adhesion structures occurred variably and clearly depended on the maturation stage and on the B and T cell origin of lymphomas but was not associated with the proliferative status of tumour cells. The concomitant expression of both adhesion molecules was a characteristic feature of germinal centre derived NHL, particularly of those with neoplastic follicular structures (corr. contingency coeff. = 0.506; P less than 0.02), whereas both adhesion structures were less often expressed on lymphomas with a more diffuse pattern of tumour infiltration. Most B-NHL of low-grade malignancy expressed LFA-1 while their counterparts of high-grade malignancy often tended to be LFA-1 negative. In B cell neoplasias of low-grade malignancy the lack of ICAM-1 and a leukaemic course of the disease were significantly correlated (P less than 0.0005). The results indicate that the differential expression of both adhesion molecules may account for distinct patterns of growth and spread in subtypes of lymphoid malignancies.

Antigens, Differentiation↗

PubMed1988

Importance of an 85 kDa membrane glycoprotein for a variety of cell-cell interactions.

The membrane molecule termed "7F7-antigen" has been found to be involved in several examples of cell-cell interactions. This 85 kDa glycoprotein with a protein core of about 55 kDa contains N-linked and O-linked carbohydrates. It has an isoelectric point of 8.0-8.5 and is expressed on 20% of peripheral blood mononuclear cells, 35% of peripheral blood B-cells, follicular dendritic cells and vascular endothelium. It is also expressed on activated T-cells and its expression on B-cells, fibroblasts and monocytes increases after treatment with PWM, interferon-gamma and after three days culture, respectively. The MAb 7F7 used to define this antigen inhibits the initiation of T-cell proliferation induced by anti-CD3, PHA, ConA and (weakly) allogenic stimulator cells, but does not affect the growth of IL-2 dependent T-cells and does not interfere with the killing of PHA-blasts by allogenic IL-2 dependent T-cells. 7F7 also inhibits the binding of C3-coated sheep erythrocytes to B-cells, the PMA-induced aggregation of U937 and the binding of activated T-cells to fibroblasts. The 7F7-antigen is expressed on some non-Hodgkin lymphomas of B-cell differentiation, particularly those with follicular structure, but not on Burkitt's lymphoma, ALL or carcinomas of various tissues. It is, however, found on fibrous tissue surrounding infiltrating carcinoma cells. The expression of a melanoma antigen, P3.58, which was shown to be identical to 7F7-antigen correlates with stage and spread of invasive melanoma. It was concluded that the 7F7-antigen, which is probably related to a previously described adherence molecule (ICAM-1), is of biological importance for the initiation of T-cell responses. With the possible exception of melanoma its expression on neoplastic cells in vivo is unlikely to be of importance for the spread of malignant disease.

Antigens, Neoplasm↗

PubMed1988

Structural and functional analysis of CR2/EBV receptor by means of monoclonal antibodies and limited tryptic digestion.

The receptor for the C3d fragment of the third component of complement, CR2, has recently been shown also to act as the receptor for the Epstein-Barr virus (EBV) and to be involved in the control of B-cell proliferation. In order to define functionally important domains on this molecule, we produced monoclonal antibodies to several distinct epitopes. CR2 was purified from a NP-40 lysate of human tonsils by a new method involving sequential chromatography on lentil lectin Sepharose 4B and DEAE-Sephadex and used to immunize mice. After fusion we obtained four stable hybridoma lines producing antibody to CR2. Specificity of these antibodies for CR2 was ascertained by immunofluorescence analysis on a panel of various cells known to possess CR2, by their reactivity in a recently described ELISA for C3 receptors, by Western blotting with purified CR2 and immunoprecipitation from 125I-labelled Raji cells. These four antibodies were found to recognize three distinct epitopes localized on the same fragments of 95,000, 72,000, 50,000, 32,000 and 28,000 MW obtained after mild tryptic digestion of CR2. The 72,000 MW fragment contains the binding site for C3d. Two monoclonal antibodies recognizing the same epitope did not inhibit the binding of C3d-coated sheep erythrocytes to Raji cells, whereas the other two antibodies against distinct epitopes did inhibit in the presence of a second antibody. All four monoclonal antibodies stimulated the proliferation of human peripheral blood B cells.

Antibodies, Monoclonal↗

PubMed1987

Involvement of complement in B-cell, T-cell and monocyte/macrophage activation.

In the early 70's it had been shown, that for the immune response against T-dependent antigens C3 was necessary, while T-independent antigens, although activating the alternative pathway of complement, triggered antibody formation also in C-deficient mice. During recent years functional and biochemical knowledge about complement binding structures on B-cells and monocytes/macrophages continuously increased and, also, on T-cells C3 binding entities have been detected. In the case of B-cells and, at least in special experimental conditions, in the case of T-cells C3 can exert a proliferative response as long as the cells are prestimulated (excited) by anti-Ig or IL-2, respectively. Monocytes can bind C3b- or iC3b-carrying particles, but only when progressed to macrophages can they phagocytose such particles. Thus the concept evolves that B-cells, T-cells and monocytes can acquire competence for a C3-driven response when excited properly. The involvement of molecules such as CR1, CR2, factor H, IL-2-receptor and others with a basic structure of repeating units of 61 amino acids in the triggering processes is a surprising finding and certainly suggests their functional importance. In the case of T-independent antigens the structures triggering the alternative pathway of complement are the structures triggering monocytes directly. Whether these two functions have a causal relationship has to be shown.

Animals↗