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N R Ling

Publications and source records attributed to N R Ling.

At least 55 records · Page 3Linked to original sources
PubMed1984

Subclasses of IgG on the surface of human lymphocytes: a study with monoclonal antibodies.

Cells from sIgG+ B lymphoblastoid cell lines, sIgG+ B cell neoplasms and from tonsils, adult and cord blood and fetal spleen were tested for IgG subclass expression using a panel of monoclonal antibodies. IgG1 was in all cases the commonest subclass except on blood lymphocytes, when approximately equal numbers of cells expressing IgG1 and IgG2 were found. No evidence for multiple subclass isotype expression was found.

Adult↗
PubMed1983

Immunogenic and antigenic epitopes of immunoglobulins--V. Reactivity of a panel of monoclonal antibodies with sub-fragments of human Fc gamma and abnormal paraproteins having deletions.

The specificity of a panel of 27 monoclonal antibodies reactive with human Fc gamma has been further defined through reactivity profiles with sub-fragments of Fc gamma and IgG paraproteins having deletions within C gamma 2 or C gamma 3. Antibodies are identified that are directed to discontinuous epitopes requiring native Fc gamma for expression. Other antibodies are reactive with isolated C gamma 2 or C gamma 3 domains. Sub-class specific and sub-class restricted antibodies allow correlation of epitope expression with primary structure.

Animals↗
PubMed1983

Monoclonal antibody against a cross-reactive idiotypic determinant found on human autoantibodies with anti-I and -i specificities.

A monoclonal antibody has been raised against a cross-reactive idiotypic determinant expressed on human autoantibodies with anti-I and -i specificities. The McAb is directed against a conformational epitope requiring interaction of H- and L-chains for maximal expression. This epitope was strongly expressed on the monoclonal protein of one out of 100 patients with paraproteinaemia and the peripheral blood lymphocytes of one out of 50 cases of B-cell leukaemia. A small amount of the epitope is detectable among immunoglobulins in normal serum.

Agglutinins↗
PubMed1983

The incidence of B cell leukaemia and lymphopenia in B cell neoplasia in adults: a study using the Kiel classification of non-Hodgkin's lymphoma.

The incidence of B cell leukaemia in 186 consecutive untreated patients with histologically defined B cell neoplasms is described. The lymphomas were classified by the Kiel convention. B cell leukaemia in the context of this paper refers to the situation where a neoplastic clone of B cells in the blood greatly outnumbers normal blood B cells. It is defined as an absolute blood B cell count greater than 0.75 X 10(9)1(-1) where either greater than 90% B cells express kappa immunoglobulin light chains or greater than 80% express lambda light chains. This was found in several patients where the total blood lymphocyte count was within normal limits. All patients with diffuse lymphocytic lymphoma with the histological appearances of B cell chronic lymphocytic leukaemia (ML-BCLL) were found to have B cell leukaemia. However, more than half these patients had blood B cell counts less than 10 X 10(9)1(-1). B cell leukaemia was also a feature in approximately 33% of patients with follicle centre cell tumours and 33% of those with lymphoplasmacytoid tumours. B cell leukaemia was not detected in 34/35 patients with myelomatosis. The 35th patient had plasma cell leukaemia. Only 3/22 patients with high grade lymphoma had B cell leukaemia. In the three principal tumour types associated with B cell leukaemia mu + delta was the most common immunoglobulin heavy chain phenotype. Spontaneous mouse red cell rosette formation also characterised leukaemic B cells in these three groups but high proportions of mouse rosetting cells were seen only in association with ML-BCLL. None of 4 cases of prolymphocytic leukaemia showed mouse red cell rosetting. HLA-DR alpha chain was found on the leukaemic cells of all patients except one with ML-BCLL. B cell lymphopenia was a frequent finding in all histological groups in those patients who did not have B cell leukaemia.

Adult↗
PubMed1983

Detection of free kappa chains in human serum and urine using pairs of monoclonal antibodies reacting with C kappa epitopes not available on whole immunoglobulins.

The properties of five monoclonal antibodies (McAbs) which react with free kappa chains but not with IgG kappa, IgM kappa or IgA kappa have been studied. IgG preparations stored for long periods sometimes contained low and high molecular weight material reacting as free kappa. This could be removed by passing the preparation through an affinity column to which two of the McAbs had been coupled, but reactive material reappeared when the purified IgG was heated at 65 degrees C. Two of the McAbs from one fusion reacted with F(ab')2 fragments of IgG whereas two from another fusion did not. Pairs of McAbs (one from each fusion) were much more sensitive in the detection of free kappa, particularly monomer, than a single McAb. This provided the basis for a very sensitive method of detection of free kappa chains in human body fluids and culture supernates.

Antibodies, Monoclonal↗
PubMed1983

Triggering of monoclonal human lymphoma B cells with antibodies to IgM heavy chains: differences of response obtained with monoclonal as compared to polyclonal antibodies.

A comparative study of human B lymphoma cells activation by monoclonal (murine hybridoma) antibodies to mu heavy chains (Ma-mu) as compared to polyclonal (rabbit) antibodies to mu heavy chains (Ra-mu) has been carried out. Early events related to calmodulin activation such as 86Rb influx and changes in cell volume at 4 h could be induced by Ma-mu. One antibody (AF6) approached Ra-mu with regard to the strength of response obtained. However, Ma-mus including AF6 were deficient in inducing DNA synthesis under conditions where this was achieved with Ra-mu. Studies in one lymphoma, where stimulation of re-expressed surface IgM could be studied, revealed that Ma-mu was deficient in stimulating re-expressed sIgM. These findings raise questions with regard to polyclonal antibody to surface Ig as a model for B cell triggering by antigen and suggest that antigen-induced B cell triggering may be more complex than indicated by previous studies with polyclonal antibody.

Antibodies, Monoclonal↗
PubMed1982

In vitro stimulation of rabbit T lymphocytes by cells expressing herpes simplex antigens.

Lymphocyte stimulation responses to herpes antigens were studied using virus-infected X-irradiated cells. Rabbits were immunized with herpes simplex virus type 1 (strain HFEM) grown in RK 13 cells. For in vitro stimulation assay BHK21 cells were X-irradiated (15 000 rad) and infected with a high m.o.i. of a temperature-sensitive (ts) mutant (N102) of HFEM strain at the non-permissive temperature (38.5 degrees C) of virus. Virus antigens were expressed on the infected cells and there was no leakage of infectious virus into the medium at 38.5 degrees C. T lymphocytes from rabbits immunized with herpes simplex virus were specifically activated by herpesvirus-infected X-irradiated cells; lymph node cells from rabbits immunized with RK13 cells and from non-immune rabbits showed no proliferative response.

Animals↗
PubMed1982

Immunogenic and antigenic epitopes of immunoglobulins. II. Antigenic differences between secreted and membrane IgG demonstrated using monoclonal antibodies.

Twenty-three monoclonal antibodies with specificity for epitopes in the Fc fragment of IgG have been used to investigate antigenic differences between secreted and membrane forms of IgG produced by 2 human B lymphoblastoid cell lines (LCL). All of the monoclonals reacted with IgG secreted by the cell lines, as demonstrated by their ability to agglutinate SRBC coated with immunoglobulin isolated from culture supernatants. Membrane IgG expression was studied using direct and indirect rosette assays with antibody-coated ORBC. A surprisingly high number of antibodies, 13 on EB2 and 9 on EB4, did not bind to the cell surface immunoglobulin. These included antibodies with specificities for both C gamma 3 and C gamma 2 domain determinants. Similar results were obtained with an indirect radiobinding assay, indicating that negative results with the rosette test were not due to steric hindrance by the red cell carrier. Their performance in indirect hemagglutination indicated that most of the antibodies that did not bind to membrane IgG were of high avidity. It is concluded that the epitopes for which these antibodies are specific are not available on the cell surface. Possible explanations for the apparent antigenic differences between secreted and membrane forms of IgG are discussed against the background of previous work on the structure and mode of insertion of cell surface immunoglobulin.

Animals↗
PubMed1982

Immunogenic and antigenic epitopes of immunoglobulins I. Cross-reactivity of murine monoclonal antibodies to human IgG with the immunoglobulins of certain animal species.

Antibody-producing hybridoma clones have been isolated following immunization of mice with human IgG. Twenty-five monoclonal antibodies (nine anti-C gamma 3, fourteen anti-C gamma 2, one anit-kappa and one anti-lambda) were selected for study of their cross-reactivity with the IgG of fifteen mammalian species and chicken immunoglobulin. Each antibody exhibited a unique reaction profile suggesting that human IgG expresses a very large repertoire of immunogenic epitopes. Whilst some antibodies showed a very restricted cross-reactivity profile for others a very wide reactivity profile was observed-including two clones producing autoantibodies. Antibodies demonstrating cross-reactivity between human Fc gamma and 7S chicken immunoglobulin allow its definitive assignment as a homologue of human IgG. Four clones demonstrated specificity for bovine IgG subclass gamma 1 and gamma 2 and the degree of reactivity allows their application to qualitative and quantitative assay systems. These studies suggest new perspectives for the characterization of immunoglobulins and the standardization of anti-immunoglobulin reagents.

Animals↗
PubMed1982

Monoclonal antibodies to the idiotypic determinants of a human IgG paraprotein: evidence for complexity of the anti-idiotype response.

BALB/c mice were immunized with a human gamma 2k paraprotein and hybridomas prepared by the Kohler & Milstein technique. Ten hybridoma clones producing high levels of antibody competed reacting specificity with the immunogen were isolated. Six of the monoclonal antibodies competed strongly with each other for sites on the antigen. In reverse passive haemagglutination tests immunoglobulins reacting with the antibodies were not detectable in normal or pathological sera. Polyclonal antisera to two of the monoclonal antibodies were prepared in rabbits; they were rendered specific by adsorption with Sepharose-normal mouse IgG and tested against the other monoclonal antibodies. A weak cross-reaction of one of the mouse antibodies with the immunogen was observed with one antiserum but none with the other. Furthermore, no repetition of the idiotypes of the two immunogens was observed in polyclonal responses of BALB/c mice immunized with the same paraprotein antigen. These results with monoclonal antibodies confirm those obtained with polyclonal antisera in showing that the antibody response of one species to the private idiotype determinants of an immunoglobulin of another species is highly heterogeneous.

Animals↗
PubMed1982

Theoretical and ultracentrifugal analysis of immune complex formation between monoclonal antibodies and human IgG.

Immune complex formation of four different mouse monoclonal antibodies against human IgG has been studied using analytical zonal centrifugation. A theoretical model has been used to depict thermodynamic ideal immune complex formation of monoclonal antibodies. It was found that the four monoclonal antibodies differed very much with respect to immune complex formation with human IgG. One of the monoclonal antibodies formed immune complexes in agreement with the theoretical model. Another was strongly related thereto. A third monoclonal antibody formed only a single complex and might exhibit a positive co-operativity between its two sites. A fourth formed as excess of a possibly cyclic complex. Thus monoclonal antibodies differ substantially with respect to physical properties adding a new aspect to the problems of antibody heterogeneity. It is moreover found that analytical zonal centrifugation can be used to estimate the number of antigenic determinants and antibody-binding sites thereby assuring whether or not a particular IgG monoclonal antibody has two binding sites.

Antibodies, Monoclonal↗
PubMed1982

Monoclonal antibodies (McAbs) to determinants on human gamma chains: properties of antibodies showing subclass restriction or subclass specificity.

Thirteen monoclonal antibodies (McAbs) showing subclass-specific and subclass-restricted reactivity to human IgG have been produced by the hybridoma technique. Their specificity has been defined by passive haemagglutination (HA) and haemagglutination-inhibition (HAI) assays using a large panel pf purified IgG paraproteins of known subclass. Their use in assaying human IgG subclasses in radial immunodiffusion (RID) and in purifying human subclasses by both positive and negative immunoabsorption chromatography is illustrated.

Animals↗
PubMed1981

Antibodies in human sera to F(ab')2 fragments of monoclonal and polyclonal IgG.

F(ab')2 fragments of human, bovine and rabbit polyclonal IgG and of human IgG paraproteins of different subclass and light-chain type have been coupled to human red cells and used to detect "agglutinator' antibodies in normal and pathological human sera. The common occurrence of such antibodies in human sera and their heterogeneity in terms of specificity have been confirmed. No change in titre or specificity was found in monoclonal B cell proliferations. The possible significance of serum agglutinators is discussed.

Animals↗
PubMed1981

Study of proteolytic removal of Fab delta and Fe delta determinants of lymphocyte membrane IgD using a direct rosette assay.

Proteolysis of lymphocyte surface membrane immunoglobulin (SIg) by trypsin, papain and pronase was investigated. Cleavage in the hinge region resulting in removal of Fab delta was distinguished from removal of the whole SIgD molecule using antisera specific for c delta l and Fc delta. Using the sensitive direct rosette assay SIgD determinants were detected after digestion under conditions previously thought to remove IgD from the membrane. By increasing digestion times is was shown that whilst papain and pronase remove the whole IgD molecule, Fc delta but not Fab delta determinants survive trypsin. The implications of the results for structural differences between membrane and serum IgD and for models of insertion of SIgD into the plasma membrane are discussed.

Epitopes↗
PubMed1981

Properties of monoclonal antibodies to human immunoglobulin kappa and lambda chains.

Hybridomas have been produced from mice immunized with human IgG. Culture supernates were assayed for the presence of antibody-producing cells by passive haemagglutination. Hybridomas producing antibodies to human kappa (kappa) and lambda (lambda) light chains have been cloned and grown as ascitic tumours in BALB/c mice. The antigen-binding characteristics of the monoclonal antibodies, contained in the ascitic fluid, were assessed by haemagglutination inhibition, ELISA and radioimmunoassay systems and by the binding of radiolabelled antigen in analytical flat-bed iso-electric focussing gels. One monoclonal anti-kappa reacted better with free than with combined kappa chains; for another the reverse was true. Antibody fractions separated by DEAE chromatography of ascitic fluids were coupled to ox red cells with chromic chloride and compared with polyclonal antibodies for the detection of cell-surface immunoglobulins.

Animals↗
PubMed1981

Monoclonal antibodies to human IgG: reaction characteristics in the centrifugal analyzer.

We used monoclonal antibodies to human IgG in a kinetic turbidimetric method with a centrifugal analyzer. Results for total IgG with monoclonal and polyclonal reagents correlated well (r = 0.979). Within- and between-batch CVs compared favorably (3.1 and 4.8%, respectively, for polyclonal antisera and 3.5 and 4.0%, respectively, for monoclonal reagents). The monoclonal antibody combination used was shown to be of high titre, with an avidity toward the lower end of the range seen with conventional antisera to IgG. It displayed reaction characteristics similar to those observed with polyclonal antisera, although the time scale of reaction was extended and the effective concentration range was narrowed. Single monoclonal antibodies may not produce complexes of a size exhibiting measurable turbidity when reacted with soluble antigen. However, evidence is presented for the incorporation of such complexes into precipitates produced by other related antigen-antibody systems.

Antibodies, Monoclonal↗