| 1. |
- Ohlin, Mats, et al.
(författare)
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Light chain shuffling of a high affinity antibody results in a drift in epitope recognition
- 1996
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Ingår i: Molecular Immunology. - : Elsevier BV. - 1872-9142 .- 0161-5890. ; 33:1, s. 47-56
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Tidskriftsartikel (refereegranskat)abstract
- Human polyclonal and monoclonal antibodies against pathogens and toxins are potentially useful in the treatment of various diseases. A number of human monoclonal antibodies with protective capacity in vitro have been established by conventional hybridoma technology. However, with the development of phage-display technology, the possibility of specifically tailoring antigen-binding properties has improved substantially. We show here that the reactivity of a high affinity, virus-neutralizing human antibody against the AD-2 epitope of cytomegalovirus gB can be modified by introducing other Vkappa sequences together with the original VH sequence. The fine specificity, as determined by the requirement of particular amino acid residues in the epitope, is shifted in these new antibody fragments. It was also evident that the VH/Vkappa pairing was not promiscuous, since antibody fragments selected by phage display retained light chain sequences very similar to the original hybridoma-derived light chain, proving that a high affinity interaction was very dependent on a co-operativity between both variable domains. These findings show that phage display technology might modify the binding properties of pre-existing, high affinity antibodies.
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| 2. |
- Ohlin, Mats, et al.
(författare)
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Restricted variable region gene usage and possible rheumatoid factor relationship among human monoclonal antibodies specific for the AD-1 epitope on cytomegalovirus glycoprotein B
- 1994
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Ingår i: Molecular Immunology. - : Elsevier BV. - 1872-9142 .- 0161-5890. ; 31:13, s. 983-991
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Tidskriftsartikel (refereegranskat)abstract
- The nucleotide sequences of the variable region genes encoding five different human, high affinity antibodies, specific for the major neutralization determinant (AD-1) expressed by human cytomegalovirus glycoprotein B (gp58/116), have been determined. Three of the five heavy chain variable regions belonged to the small VHV-family, although they combined with a diverse set of light chains (V kappa IIIb, V lambda II and V lambda III). The other two antibodies belonged to VH-families III and IV. One of the VHV-family genes most likely originated from a previously unreported germline gene or allele, since it carries a nine nucleotide insert in framework 1. In addition, V lambda-genes showed variable homology (77-95%) to known germline sequences, while V kappa-genes showed high homology (approximately 98%) with their proposed germline origin. Despite the close homology of the V kappa IIIb-gene used to express one of the antibodies with its corresponding germline gene, the protein did not strongly express some idiotypes associated with this light chain family. There is, thus, no direct relation between the expression of these crossreactive idiotypes and the use of even modestly mutated light chains belonging to this V kappa-family, which has been implicated in the development of anti-idiotypic networks possibly inducing autoantibodies, such as rheumatoid factors.
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| 3. |
- Sabharwal, H, et al.
(författare)
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Blood group specific oligosaccharides from faeces of a blood group A breast-fed infant
- 1984
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Ingår i: Molecular Immunology. - : Elsevier BV. - 1872-9142 .- 0161-5890. ; 21:11, s. 1105-1112
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Tidskriftsartikel (refereegranskat)abstract
- Four different oligosaccharides were isolated from faeces collected from a blood group A, secretor, breast-fed infant. Three of these, GalNAc alpha 1-3[Fuc alpha 1-2]Gal beta 1-4Glc (A-tetrasaccharide), GalNAc alpha 1-3[Fuc alpha 1-2]Gal beta 1-4[Fuc alpha 1-3]Glc (A-pentasaccharide) and 1-3[Fuc alpha 1-4]GlcNAc beta 1-3Gal beta 1-4Glc (A-heptasaccharide) have previously found in urine, whereas GalNAc alpha 1-3[Fuc alpha 1-2]Gal beta 1-3GlcNAc beta 1-3Gal beta 1-4Glc (A-hexasaccharide) is a new compound. Structures were deduced by mass spectrometry of permethylated and N-trifluoroacetylated oligosaccharide alditols. The latter gave more structural information than the corresponding N-acetyl derivatives. The four oligosaccharides were tested for blood group A activity and all were found to inhibit the binding of anti-A antibody to blood group A substance.
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| 4. |
- Wingren, Christer, et al.
(författare)
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Antigen-binding sites dominate the surface properties of IgG antibodies
- 1995
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Ingår i: Molecular Immunology. - 1872-9142 .- 0161-5890. ; 32:11, s. 819-827
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Tidskriftsartikel (refereegranskat)abstract
- A new technique, liquid-liquid partition chromatography in an aqueous polyethylene glycol-dextran two-phase system, was used to detect differences in surface properties of antibodies with different antigen-binding sites. Employing well-characterized monoclonal IgG antibodies and Fab and Fc fragments thereof as well as chimeric IgG antibodies we found a remarkable relationship between structure of the antibody combining site and chromatographic behaviour. The surface properties of the IgG antibodies were dominated by those of its antigen-binding regions. In addition, our results indicated that the constant parts of the IgGs form similar scaffoldings, on to which CDRs of variable shapes and sizes are interspaced and constitute the major dominant differences in exposed surface properties.
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| 5. |
- Kärkkäinen, T, et al.
(författare)
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Isolation and immunologic properties of a heterogeneous antigen with the characteristics of the heavy chain of human plasma kininogen
- 1982
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Ingår i: Molecular Immunology. - : Elsevier BV. - 0161-5890 .- 1872-9142. ; 19:1, s. 179-189
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Tidskriftsartikel (refereegranskat)abstract
- Kininogen antigen was purified from human plasma fraction IV by ion exchange chromatography, gel filtration and affinity chromatography with antibody specific immunoadsorbents. The immunologically pure glycoprotein had a mol. wt of approximately 60,000 and only one polypeptide chain by SDS-PAGE. An extensive charge heterogeneity by isoelectric focusing and gel filtration on polyacrylamide agarose could only in part depend on a comparatively high sialic acid content, but may be caused by differences in the carbohydrate structures sustained by lectin-binding heterogeneity on Con A-Sepharose. This antigen shares a dominating determinant with native plasma kininogens shown by complete patterns of identity in immunochemical analyses and with the monospecific antisera developed in rabbits against the heterogeneous components. The similar size, amino acid composition, low histidine content, lack of N-terminal amino acid and antigenic homogeneity fit all the so far known characteristics of the human kininogen heavy chain. Notably the antigenic determinant is resistant to degradation by activated kallikrein. This antigen with unimpaired immunologic activity may be a useful tool for preparation of antiserum for immunochemical determination of human plasma kininogen.
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| 6. |
- Nilsson, Bo, et al.
(författare)
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Distinctive expression of neoantigenic C3(D) epitopes on bound C3 following activation and binding to different target surfaces in normal and pathological human sera
- 1989
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Ingår i: Molecular Immunology. - : Elsevier BV. - 0161-5890 .- 1872-9142. ; 26:4, s. 383-390
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Tidskriftsartikel (refereegranskat)abstract
- Binding of C3 to sheep erythrocytes in a serum-free milieu (EAC14oxy2, EAC142) has previously been shown to mimic the antigenic change that occurs upon denaturation of C3 in sodium dodecyl sulphate (SDS), whereby neoantigenic C3(D) epitopes are exposed. The present paper deals with C3 bound to various target surfaces which are known to modulate the functional properties of C3 in different ways. Bound C3 fragments on serum-treated human aggregated gammaglobulin, zymosan, rabbit and sheep erythrocytes, and on circulating immune complexes isolated from sera of patients with rheumatoid arthritis and systemic lupus erythematosus, were shown to be mainly in the iC3b form. By RIAs, employing polyclonal antibodies, the range of C3(D) antigenic epitopes of 125I-labelled SDS denatured C3 expressed by the particle-bound iC3b was monitored. The physiologically bound iC3b on all tested particles expressed wide ranges of C3(D) epitopes and each type of particle-bound C3 exposed its individual range. By competition ELISA specific C3(D)α epitopes were monitored, employing monoclonal antibodies. A distinct difference in the expression of these epitopes was observed in iC3b bound to various test particles in the presence of normal serum and in iC3b present on circulating immune complexes from pathological sera. Considering that the neoantigenic C3(D) epitopes have been shown to be associated with different functions of C3, the distinctive antigenic expression of each type of serum-treated particle might reflect different functional forms of the protein.
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| 7. |
- Syvänen, Ann-Christine, et al.
(författare)
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Conformation and sequence dependent antigenic determinants in human low molecular weight kininogen
- 1983
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Ingår i: Molecular Immunology. - : Elsevier BV. - 0161-5890 .- 1872-9142. ; 20:6, s. 669-678
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Tidskriftsartikel (refereegranskat)abstract
- Conformation and sequence-dependent antigenic determinants were investigated using a kinin-free low molecular weight kininogen isolated from Cohn's plasma fraction IV. This antigen contains the determinants of the apparently intact heavy chain common to the high molecular weight and low molecular weight kininogens. Straightforward reduction and carboxymethylation destroyed the immunoreactivity of this molecule. Antiserum prepared against the reduced protein recognized both reduced and unreduced antigen showing the presence of both types of antigenic determinant. The corresponding antibodies were separated using immunoadsorbent columns. As shown by the higher avidity of the antibodies, the conformation-dependent determinants dominate the antigenic structure.
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| 8. |
- Truedsson, Lennart
(författare)
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Classical pathway deficiencies - A short analytical review.
- 2015
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Ingår i: Molecular Immunology. - : Elsevier BV. - 1872-9142 .- 0161-5890. ; 68:1, s. 14-19
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Forskningsöversikt (refereegranskat)abstract
- Deficiencies in the classical pathway of complement activation have some common features but show also great differences. Deficiencies of each of the components (C1q, C1s, C1r, C4 and C2) imply increased susceptibility to bacterial infections. They are also associated with increased risk to develop systemic lupus erythematosus where deficiency of C1q is strongly associated to the disease while C4 less and C2 much less. Deficiency of C1q affects only activation of the classical pathway while deficiency of C4 and C2 also prevent activation of the lectin pathway. Bypass mechanisms may result in complement activation also in absence of C2 but not in absence of C1q or C4. The genes for C2 and C4 isotypes are closely located within the MHC class III region on chromosome 6p and the genes for the 3 C1q chains are on chromosome 1p. Deficiencies of C1q and of C4 show genetic heterogeneity while deficiency of C2 in the great majority of cases is caused by a specific deletion. The production of C4 and C2 is mainly by the hepatocytes in the liver while C1q is produced by monocytic bone marrow derived cells. This has implications for the possibility to treat the deficiency and hematopoietic stem cell transplantation has been tried in C1q deficiency.
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| 9. |
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| 10. |
- Amano, Mariane T, et al.
(författare)
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Genetic analysis of complement C1s deficiency associated with systemic lupus erythernatosus highlights alternative splicing of normal C1s gene
- 2008
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Ingår i: Molecular Immunology. - : Elsevier BV. - 1872-9142 .- 0161-5890. ; 45:6, s. 1693-1702
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Tidskriftsartikel (refereegranskat)abstract
- Deficiencies of complement proteins of the classical pathway are strongly associated with the development of autoimmune diseases. Deficiency of Clr has been observed to occur concomitantly with deficiency in Cls and 9 out of 15 reported cases presented systemic lupus erythernatosus (SLE). Here, we describe a family in which all four children are deficient in Cls but only two of them developed SLE. Hemolytic activity mediated by the alternative and the lectin pathways were normal, but classical pathway activation was absent in all children's sera. Cls was undetectable, while in the parents' sera it was lower than in the normal controls. The levels of Clr observed in the siblings and parents sera were lower than in the control, while the concentrations of other complement proteins (C3, C4, MBL and MASP-2) were normal in all family members. Impairment of Cls synthesis was observed in the patients' fibroblasts when analyzed by confocal microscopy. We show that all four siblings are homozygous for a mutation at position 938 in exon 6 of the Cls cDNA that creates a premature stop codon. Our investigations led us to reveal the presence of previously uncharacterized splice variants of Cls mRNA transcripts in normal human cells. These variants are derived from the skipping of exon 3 and from the use of an alternative 3' splice site within intron I which increases the size of exon 2 by 87 nucleotides.
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