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R Jefferis

Publications and source records attributed to R Jefferis.

At least 109 records · Page 6Linked to original sources
PubMed1988

Incidence of three cross-reactive idiotypes on human rheumatoid factor paraproteins.

The basis for rheumatoid factor (RF) production in autoimmune or lymphoproliferative diseases cannot be understood without defining the molecular factors that dictate RF structure and specificity. Recently three different mAb (6B6.6, 17.109, and G6) have been developed that define cross-reactive idiotypes (CRI) on intact L or H chains of human monoclonal RF cryoglobulins. However, the true incidence of these CRI among RF and their relationship to each other have not been delineated. In the present experiments, a panel of 163 randomly selected IgM paraproteins was evaluated for the expression of the two kappa L chain CRI, 6B6.6 and 17.109, and the H chain CRI, G6. Among the paraproteins with kappa L chains, 14% expressed the 17.109 CRI, and 9% expressed the 6B6.6 CRI. Both ELISA and Western immunoblotting experiments showed that the two L chain CRI were mutually exclusive. Anti-IgG activity was documented in 22 of the IgM-kappa paraproteins, among which mAb 6B6.6 reacted with 7 (32%) and mAb 17.109 with 6 (27%). Both CRI were expressed exclusively by L chains within the kappaIII variable gene subgroup. Although 17.109 CRI+ paraproteins had kappaIIIb L chains, none of the 6B6.6 CRI+ paraproteins possessed L chains with this kappa sub-subgroup specific Ag. The G6 CRI was found predominantly among RF paraproteins and was frequently yet not exclusively associated with the 17.109 CRI+ L chains. Additional experiments were performed on a panel of normal adult human sera and documented the presence of 6B6.6 and 17.109 CRI on a small percentage (0.1 to 2.0%) of IgM from most individuals. These data indicate that 1) the mAb 6B6.6 and 17.109 identify two major and distinct CRI among IgM-RF paraproteins, 2) both CRI are associated exclusively with kappaIII L chains, 3) kappaIIIb and kappaIII non-b L chains are equally prevalent among IgM-RF, 4) the G6 H chain CRI is frequently associated with 17.109 CRI+ L chains, but not with 6B6.6 CRI+ L chains, and 5) although the ability to make 6B6.6 and 17.109 CRI+ kappa L chains is common in humans, these CRI are present in low concentrations in normal IgM.

Adolescent↗
PubMed1988

Immunogenic and antigenic epitopes of Ig. XXV. Monoclonal antibodies that differentiate the Mcg+/Mcg- and Oz+/Oz- C region isotypes of human lambda L chains.

The C region of human lambda L chains is specified by multiple C lambda genes of which three--C lambda 1, C lambda 2, and C lambda 3--encode for the isotypes designated Mcg+, Kern- Oz-, and Kern- Oz+, respectively. The Mcg, Kern, and Oz factors have been characterized by sequence differences involving specific C lambda amino acid residues. They have also been recognized serologically by polyclonal antisera but, with rare exception, these reagents are no longer available. We have obtained two murine anti-human lambda-chain mAb, 14G1 and 14D1, that recognize antigenic determinants specific for the C lambda isotypes Mcg and Oz, respectively. These antisera have been used to classify as Mcg+/Mcg- or Oz+/Oz- monoclonal lambda-chains (Bence Jones proteins) and intact Ig lambda proteins. There was complete concordance between the chemical and serologic assignment of lambda-chains as Mcg+/Mcg- or as Oz+/Oz-; no single protein expressed both isotypes. There was no evident association between the C region isotype Mcg or Oz and the V region subgroup of the protein tested. However, our finding that four of seven amyloid-associated lambda VI Bence Jones proteins were Oz+ suggests a predominant expression of the C lambda 3 gene product among proteins of this uncommon V lambda subgroup.

Animals↗
PubMed1988

Molecular recognition of antibody (IgG) by cellular Fc receptor (FcRI).

Earlier studies from this and other laboratories have provided indirect evidence for the involvement of the C gamma 2 domain of human IgG in the binding of IgG to the high affinity monocyte Fc receptor (FcRI). Two approaches have been used to extend these studies and to further localize the site of interaction on human IgG. Firstly, monoclonal antibodies (MAbs) directed against different epitopes on IgG were assayed for their capacity to inhibit the binding of radiolabelled IgG to human monocytes or U937 cells. The capacity of the MAbs to interact with their respective epitopes on FcR-bound IgG was also studied using indirect radiobinding and immunofluorescence assays. Secondly, a number of IgGs from several different species and fragments of human IgGs were assayed for their ability to inhibit the binding of radiolabelled IgG to human monocytes. The amino acid sequences of those IgGs exhibiting relatively tight, intermediate or weak binding to monocyte FcRs were compared. On the basis of these studies a possible monocyte FcR-binding site on human IgG is postulated, involving the lower hinge region of IgG (residues Leu 234-Ser 239) with possible involvement of the nearby N-proximal bend and two beta-strands (Gly 316-Lys 338).

Amino Acid Sequence↗
PubMed1988

Immunogenic and antigenic epitopes of immunoglobulins. XXIII. Idiotypy and molecular specificity of human rheumatoid factors: analysis of cross-reactive idiotype of rheumatoid factor paraproteins from the Wa idiotype group in relation to their IgG subclass specificity.

The expression of idiotypic and variable region-associated isotypic determinants on a panel of human monoclonal rheumatoid factors (RF) was studied by means of murine hybridoma antibodies produced to two IgM-RF paraproteins. Fourteen RF paraproteins from patients with cryoglobulinaemia and one (RF-AN) from an Epstein-Barr virus (EBV)-established B-cell line from a patient with rheumatoid arthritis (RA) were studied. Nine RF paraproteins expressed a VkIIIb light chain sub-subgroup-associated cross-reactive idiotype and seven of these nine also expressed a heavy chain-associated cross-reactive idiotype. The reactivity of the monoclonal RF with human IgG subclass paraproteins revealed four patterns of molecular specificities: (1) RF reactive with an epitope common to all IgG subclasses; (2) RF reactive with an epitope expressed on IgG1, 2, 4 and G3m(s,t) which has histidine at 435, but not G3m(b) or G3m(g) which have arginine at 435; (3) RF reactive with an epitope expressed on IgG1, 2, and 4, but not IgG3 irrespective of allotypic markers; (4) RF reactive with epitopes expressed on some, but not all paraproteins within the subclasses. Four of five RF paraproteins that expressed both the heavy and light chain-associated idiotopes showed a similar pattern of reactivity with IgG subclass proteins.

Cross Reactions↗
PubMed1988

Immunogenic and antigenic epitopes of immunoglobulins binding of human monoclonal anti-D antibodies to FcRI on the monocyte-like U937 cell line.

Seventeen human monoclonal IgG1- or IgG3 anti-D-secreting clones have been examined for their ability to sensitise O+ red cells for Fc-receptor-mediated rosette formation with U937 cells. IgG3 but not IgG1 anti-D antibodies were able to mediate stable rosette formation with unstimulated U937 cells via interaction with the FcRI receptor. Decreasing FcRI density by incubating U937 cells with di-butyryl cAMP almost completely abolished rosette formation, whilst increasing FcRI density by incubating U937 cells with interferon-gamma increased the percentage of cells forming rosettes with IgG3- and IgG1-sensitised red cells. These data suggest that rosette formation between IgG anti-D-sensitised red cells and FcRI-expressing cells is dependent upon the density of IgG3 on the red cell surface, the density of FcRI on the effector cell, multiple FcRI/IgG interactions are required for stable rosette formation and that more FcRI/IgG1 than FcRI/IgG3 interactions are required.

Binding Sites, Antibody↗
PubMed1988

Idiotypic and subgroup analysis of human monoclonal rheumatoid factors. Implications for structural and genetic basis of autoantibodies in humans.

Rheumatoid factors (RFs) in humans have been studied intensively because of their association with autoimmune and lymphoproliferative diseases. Many human IgM-RFs express cross-reactive idiotypes (CRIs) and have homologous light chains, some of which are encoded by a single V kappa gene, termed V kappa 325. However, although antibody activity generally requires the interaction between heavy and light chain variable regions, much less is known about structural relationships among RF heavy chains. To delineate further the structural and genetic basis of RF autoantibody synthesis, we generated "sequence-dependent" reagents specific for the human heavy and kappa light chain subgroups, and used them to analyze a panel of 27 monoclonal RFs. In addition, these proteins were tested for the expression of a heavy chain-associated CRI (G6), and a light chain-associated CRI (17.109). The results showed that most 17.109-reactive RFs contain heavy chains of the VHI subgroup, which bear the G6 idiotypic marker. However, among the 14 17.109-reactive RFs, two have heavy chains of the VHII subgroup, and another two contain heavy chains of the VHIII subgroup. Previously, we have shown that 17.109 is a phenotypic marker of the human V kappa 325 gene. Accordingly, these results demonstrate that the same human V kappa gene can combine with several VH genes from different VH gene subgroups to generate RF activity.

Amino Acid Sequence↗
PubMed1988

The epitope specificity and idiotypy of monoclonal rheumatoid factors.

Monoclonal rheumatoid factors (MRF) of the Wa idiotypic family have been studied for Fc gamma epitope specificity and the expression of idiotopes recognized by murine monoclonal antibodies. The majority of MRF recognized the Ga antigen or a closely similar iso-allotypic epitope expressed on IgG1, 2, 4 and IgG3.G3m(s.t.) proteins. MRF having the iso-allotypic specificity expressed a similar profile of V-region sub-group and idiotypic serological markers. One protein, Kas, whilst recognizing a distinct Fc gamma epitope also expressed these V-region markers and was highly homologous, from primary sequence analysis, with a MRF of Ga specificity. We conclude that these MRF recognize overlapping non-identical epitopes possibly including the same immuno-dominant residue and consequently demonstrate restricted V-gene usage.

Antibodies, Monoclonal↗
PubMed1988

Analysis of rheumatoid factor autoantibodies in patients with essential mixed cryoglobulinaemia and rheumatoid arthritis.

Approximately 60% of human monoclonal rheumatoid factors from unrelated patients with cryoglobulinaemia share a common idiotype (Wa). Analysis of Ig V regions revealed that these rheumatoid factors utilize highly homologous light chains from the VKIIIb sub-subgroup. More recent studies showed a similar restriction in the use of VHI and JH4 and a restriction in the size of the D segment. In the present experiments the structural features of RFs from patients with cryoglobulinaemia were studied using a panel of murine monoclonal antibodies. The pattern of expression of these idiotypes were investigated among diverse patients with rheumatoid arthritis and normal individuals. Though in general higher levels of crossreactive idiotypes from the Wa group are detected in rheumatoid arthritis patients compared to normals, their levels in polyclonal rheumatoid factors is low. Therefore the major proportion of polyclonal rheumatoid factors in rheumatoid arthritis represent the products of somatic variants of monoclonal rheumatoid factor V genes or a larger gene pool.

Antibody Specificity↗
PubMed1987

Comparison of the effector functions of human immunoglobulins using a matched set of chimeric antibodies.

Cell lines have been established that secrete a matched set of human chimeric IgM, IgG1, IgG2, IgG3, IgG4, IgE, and IgA2 antibodies that are directed against the hapten 4-hydroxy-3-nitrophenacetyl. These chimeric antibodies secreted from mouse plasmacytoma cells behave exactly like their authentic human counterparts in SDS-PAGE analysis, binding to protein A and in a wide range of serological assays. The antibodies have been compared in their ability to bind human C1q as well as in their efficacy in mediating lysis of human erythrocytes in the presence of human complement. A major conclusion to emerge is that whereas IgG3 bound C1q better than did IgG1, the chimeric IgG1 was much more effective than all the other IgG subclasses in complement-dependent hemolysis. The IgG1 antibody was also the most effective in mediating antibody-dependent cell-mediated cytotoxicity using both human effector and human target cells. These results suggest that IgG1 might be the favoured IgG subclass for therapeutic applications.

Animals↗
PubMed1987

Immunogenicity and antigenicity of immunoglobulins: detection of human immunoglobulin light-chain carbohydrate, using concanavalin A.

Concanavalin A binding to glycoprotein bands on nitrocellulose blots was used to detect mannose, sorbose, N-acetylgalactosamine and/or glucose residues on 100% (31/31) of human Bence Jones protein light chains, following sodium dodecyl sulphate-polyacrylamide gel electrophoresis. All (20/20) light chains form IgG myeloma proteins and light chains from a preparation of normal polyclonal human IgG were also bound by concanavalin A. The specificity of concanavalin A for glycoproteins was demonstrated by its binding to human Fc fragments and a human monoclonal anti-Rhesus D antibody (REG-A), but not to human albumin pFc' fragments and aglycosylated REG-A derived from cells grown in the presence of the glycosylation inhibitor tunicamycin. These results suggest that all Bence Jones proteins and light chains from myeloma IgG proteins contain mono- or oligosaccharides linked O-glycosidically to serine or threonine residues.

Acetylgalactosamine↗
PubMed1987

Complete amino acid sequences of variable regions of two human IgM rheumatoid factors, BOR and KAS of the Wa idiotypic family, reveal restricted use of heavy and light chain variable and joining region gene segments.

Evidence derived from the complete amino acid sequences of the variable regions of both the heavy and light chains of two members (BOR and KAS) of the Wa idiotypic family of human rheumatoid factors suggests that not only are the light chains of these molecules derived from possibly one variable region gene segment, but the heavy chain variable regions are all derived from the VHI subgroup of human V region genes. These molecules exhibit a surprising conservation in the size of D region, and all use the JH4 gene element. This restriction in use of VL, VH, D, and JH suggests all of these elements may play a crucial role in either antigen binding and/or expression of the crossreactive idiotype.

Amino Acid Sequence↗
PubMed1987

Activation of human B cells: alternate options for initial triggering and effects of nonmitogenic concentrations of anti-IgM antibodies on resting and activated cells.

The monoclonal antibody 1F5, which is reactive with the CD20 (Bp 35) pan-B cell antigen, was shown to activate resting human peripheral blood B cells into the middle to late G1 phase of the cell cycle. However, in contrast to F(ab')2 fragments of polyclonal anti-mu, 1F5 synergized only weakly with B cell growth factor (BCGF) for DNA synthesis in these cells. We provide evidence that the CD20 molecule and surface immunoglobulin represent two alternative activation pathways in resting B cells. We also show that anti-immunoglobulins, during co-stimulation with BCGF, may play an important role in G1 as well as for the initial cell triggering. Thus, anti-mu in nonmitogenic concentrations was shown to provoke distinct effects on 1F5-pretreated G1 cells, as monitored by increases in cellular volumes as well as in cytoplasmic Ca2+ levels. Moreover, anti-mu could increase c-myc mRNA levels in 1F5-primed cells, implying that c-myc expression can be regulated in G1 as well as during the initial G0 to G1 transition. Partially purified human BCGF neither induced G1 entry in resting peripheral blood cells nor primed the cells for DNA synthesis. The finding that BCGF did not influence c-myc mRNA levels in resting or in activated B cells suggests that its mitogenic action does not involve the c-myc function.

Antibodies, Anti-Idiotypic↗
PubMed1987

Comparative structural study of the N-linked oligosaccharides of human normal and pathological immunoglobulin G.

The structures of oligosaccharides of normal and pathological immunoglobulin G (IgG) are reported. Asparagine-linked neutral oligosaccharides were released by N-oligosaccharide glycopeptidase (almond) digestion. The reducing ends of the oligosaccharide chains thus obtained were aminated with a fluorescent reagent, 2-aminopyridine, and the mixture of pyridylamino derivatives of the oligosaccharides was separated by reverse-phase high-performance liquid chromatography. It was possible to separate 15 out of the 16 kinds of oligosaccharides that have been suggested to exist in normal human IgG. High-resolution proton nuclear magnetic resonance spectroscopy was used along with chemical methods to determine the structures of the separated oligosaccharides. It has been shown that in normal IgG a biantennary complex-type oligosaccharide with a fucose residue (formula; see text) is predominant and four kinds of oligosaccharides, which are biantennary with bisecting N-acetylglucosamine and without fucose residues, exist only in a very small quantity. The results obtained for normal IgG were compared with those obtained for three myeloma IgG proteins. It has been found that the most abundant species that exist in the pathological proteins analyzed in the present work lack one or two galactose residues at the nonreducing terminal. We show that the fractions of fucose-containing oligosaccharides are markedly decreased in the heavy-chain disease protein Per. It is of particular interest that in this paraprotein the major component is a biantennary complex-type oligosaccharide that lacks a fucose residue and an oligosaccharide with the structure (Formula: see text) exists as one of the most abundant components.

Asparagine↗
PubMed1987

Immunogenic and antigenic epitopes of immunoglobulin--XX. Denaturation of human IgG3 by free radicals.

It has previously been demonstrated that exposure of polyclonal IgG to free radicals results in denaturation evidenced by aggregation, auto-fluorescence and destruction of cysteine, proline and aromatic amino acids. In the present study we have used a panel of monoclonal antibodies (McAb) to epitopes expressed on the IgG3 heavy chain to detect changes in antigenicity. When IgG3 was exposed to u.v. irradiation, as a source of free radicals, subclass specific epitopes were rapidly lost whilst other epitopes were unaffected. Prolonged exposure resulted in further denaturation and a progressive loss of expression of further epitopes. The IgG3 subclass specific McAb are specific to epitopes localized to the hinge region of IgG3. Thus, this exposed cysteine and proline rich region is shown to be particularly vulnerable to free radical attack; however, prolonged exposure results in structural alterations throughout the heavy chain.

Chromatography, High Pressure Liquid↗
PubMed1987

The solution conformations of the subclasses of human IgG deduced from sedimentation and small angle X-ray scattering studies.

The solution conformations of human immunoglobulin G subclass molecules have been investigated by sedimentation and small-angle X-ray scattering techniques. Both methods qualitatively indicate IgG3 to be an extended molecule relative to IgG1. Sedimentation data have been collected for a number of paraproteins of all four subclasses and the hinge-deleted IgG1Dob protein. The known crystal structure of Dob allows the use of this protein as a basis for the proposal of models of the average conformations of IgG subclasses which are consistent with experimental s(0)20,w values. IgG1 is suggested to have a hinge length of 0-15 A and non-coplanar Fab arms; IgG2 to be effectively hingeless with folded-back Fab arms; IgG3 to have an extended hinge of the order of 100 A and IgG4 to be effectively hingeless and T-shaped. The possible correlation of these conformations with subclass function is discussed.

Humans↗