Human Anti-tetanus Toxoid Research Articles

Reduction of human anti-tetanus toxoid antibody in hu-PBL-SCID mice by immunodominant peptides of tetanus toxoid.

Immunotherapy of murine autoimmune and allergic diseases by administration of peptides corresponding to the dominant T cell epitope is a reality. However, problems remain in applying this therapy to reduce antibody responses in humans. To overcome these difficulties, a preclinical system was developed to test the effect of immunodominant peptides from a common antigen, tetanus toxoid (TT), on the long-term human anti-TT response. Individuals whose T cells proliferated against dominant TT peptides were identified. Peripheral blood leucocytes (PBL) from these donors were injected intraperitoneally (i.p.) into mice with severe combined immunodeficiency (SCID) that had been depleted of murine natural killer (NK) cells (hu-PBL-SCID mice). Peptides or PBS were injected i.p. before a further injection of PBL and immunization with TT. The concentration of human IgG and anti-TT in murine plasma was followed for 10 weeks. The total IgG was similar in both groups. By contrast, there was a statistically significant reduction in IgG anti-TT from eight weeks onwards. It is considered that the hu-PBL-SCID model system may provide a means by which the efficacy of peptide immunotherapy for reduction of pathological antibodies in humans can be examined.

Feasibility studies of large scale production of human anti-tetanus toxoid monoclonal antibodies

The feasibility of large scale production of human anti-tetanus toxoid monoclonal antibody for therapeutic use was evaluated using a human heterohybridoma. The effects of duration of subculture, transition from static to agitated culture conditions and the level of serum concentration were studied. The level of antibody secreted by the clone decreased with increasing length of subculture and decreasing serum concentration. The clone exhibited heterogeneity in expression of surface IgG after 2 or 7 weeks of subculture in static culture conditions irrespective of the serum concentration. However, a prolonged duration of subculture (9 weeks) in 3% serum medium had an effect on the expression of surface IgG both in static and agitated culture conditions. With respect to total (surface and intracellular) IgG, two distinct cell populations were observed. On long term subculture (9 weeks) in low serum medium (3% FCS), there was a decrease in the population which was the high synthesizer. In addition, when these cells were cultivated in agitated spinner flasks, a defect in secretion of antibodies was observed. Thus a general fall in the amount of antibody in the supernatant of agitated cultures was due to decrease in antibody synthesis as well as the defect in secretion of antibodies.

Optimisation of human anti-tetanus toxoid antibody responses and location of human cells in SCID mice transplanted with human peripheral blood leucocytes

A strategy for the production of human antibodies to tetanus toxoid (TT) is described. Human peripheral blood lymphocytes (PBL) were injected into severe combined immunodeficient (SCID) mice (termed hu-PBL-SCID) and the mice subsequently immunised with purified TT. By using low immunising doses of antigen, PHA activated PBL and PBL from donors who were recently immunised with TT, we established ongoing antibody responses to TT with specific recall IgG responses of up to 22 IU ml-1 in the murine plasma, which was greater than that in the donors' serum. Total IgG concentrations of up to 6 mg ml-1 were detected over a 32 week period. Lower levels of IgM and IgM anti-TT were also detected over this time. Large cellular infiltrations of human CD45+ and CD20+ cells were detected by immunocytochemistry in the mesenteric membranes, mesenteric lymph nodes and the pancreas 5 weeks after PBL were engrafted into a SCID mouse. Human cells were also observed in the lungs, liver, thymus and spleen. Cells isolated from the tissues were cultured with Epstein-Barr virus and the resulting B-cell lines produced Ig in vitro up to 7 weeks, with IgG and IgM anti-TT detected transiently in a culture of cells from the mesenteric membranes.

Impaired human responses to tetanus toxoid in vitamin A-deficient SCID mice reconstituted with human peripheral blood lymphocytes.

Vitamin A deficiency is associated with increased childhood morbidity and mortality from respiratory and diarrheal diseases. In order to evaluate the effect of vitamin A on human antibody responses, we developed a vitamin A-deficient severe combined immunodeficient (SCID) mouse model. Vitamin A-deficient mice were produced by depriving them of vitamin A at day 7 of gestation. Mice were reconstituted with human peripheral blood lymphocytes (huPBL) from tetanus toxoid immune donors at 6 weeks of age and immunized with tetanus toxoid at 6 and 8 weeks of age. Secondary human antibody responses were determined 10 days later. The geometric mean human anti-tetanus toxoid immunoglobulin G concentrations were 3.75 micrograms/ml for the deficient mice and 148 micrograms/ml for controls (P = 0.0005). Vitamin A-deficient mice had only a 2.9-fold increase in human anti-tetanus toxoid antibody compared with a 74-fold increase in controls (P < 0.01). Supplementation with vitamin A prior to reconstitution restored human antibody responses to normal. These data suggest that vitamin A deficiency impairs human antibody responses. We speculate that impaired responses could increase susceptibility to certain infections. Furthermore, we propose that effects of other nutritional deficiencies on the human immune system could be evaluated in the SCID-huPBL model.

The role of tyrosine phosphorylation and Ca2+ accumulation in Fc gamma-receptor-mediated phagocytosis of human neutrophils.

When stimulated with an insoluble immune complex consisting of tetanus toxoid and human anti-tetanus toxoid IgG antibody, human neutrophils recognized the immune complex via Fc receptors (Fc gamma RII and Fc gamma RIIIB) on their plasma membranes, resulting in Ca2+ accumulation, and finally phagocytosed the immune complex. Ca2+ depletion experiments suggest that Ca2+ accumulation is essential for the maximal phagocytic activity. A tyrosine kinase inhibitor, genistein, inhibited the phagocytosis of immune complex. Genistein also inhibited both the later prolonged Ca2+ accumulation below 100 microM, and the initial rapid Ca2+ accumulation above 100 microM. Stimulation of human neutrophils by immune complexes through Fc gamma Rs caused tyrosine phosphorylation of multiple neutrophil proteins within 15 s, proceeding to an increase in the intracellular Ca2+ concentration. A similar pattern of tyrosine phosphorylation was observed when Fc gamma RII or Fc gamma RIIIB was aggregated by an anti-Fc gamma R monoclonal antibody and anti-mouse Ig. These results suggest that tyrosine phosphorylation mediates, at least in part, the later responses (Ca2+ accumulation and phagocytosis) of the cells and is an important early step in signaling via Fc gamma Rs.

Expression and Characterization of Recombinant Anti-Rh(D) Antibodies on Filamentous Phage: A Model System for Isolating Human Red Blood Cell Antibodies by Repertoire Cloning

The production of human anti-red blood cell (RBC) Igs in vitro from immunized individuals would greatly facilitate the genetic analysis of the human immune response to RBC antigens and also provide useful serologic reagents. Technical difficulties inherent in human B-cell immortalization have led to the development of molecular approaches that bypass the need for cell transformation. By cloning human Ig gene segments into bacterial expression vectors, libraries are created of filamentous phage particles displaying Fab fragments on their surfaces. Libraries have been screened with purified, soluble antigen and selected clones genetically manipulated in Escherichia coli to produce soluble Fab fragments. Our goal has been to adapt this technique to the study of RBC autoantibodies and alloantibodies that have specificities against unpurifiable membrane-bound antigens. To test the feasibility of this approach, two sets of phage were created, one set expressing a human anti-Rh(D) Ig and the other expressing a human antitetanus toxoid Ig. After verifying the presence of functional phage-displayed Fabs through biochemical, flow cytometric, and electron microscopic analyses, a model library was constructed comprising one anti-Rh(D)-expressing phage per 10(4) antitetanus toxoid-expressing phage. A method was developed for screening the library with intact Rh(D)-positive RBCs. After four rounds of panning, anti-Rh(D) specificity was enriched more than 10,000-fold to a final frequency of approximately 100%. Plasmid DNA derived from anti-Rh(D) phage was used to produce milligram quantities of soluble recombinant anti-Rh(D) Fabs purified by nitrogen cavitation and nickel-chelation affinity chromatography. The authenticity of the Fabs was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting, which showed bands with molecular weights of approximately 50 kD and 26 kD under nonreducing and reducing conditions, respectively. Binding of recombinant anti-Rh(D) Fabs to Rh(D)-positive RBCs was demonstrated by flow cytometry and by an agglutination assay. Our results suggest that repertoire cloning by cell-surface enrichment may have broad application to the study of the human immune response to erythroid antigens in addition to membrane-bound antigens present on other hematopoietic cells.

Expression and characterization of recombinant anti-Rh(D) antibodies on filamentous phage: a model system for isolating human red blood cell antibodies by repertoire cloning

The production of human anti-red blood cell (RBC) Igs in vitro from immunized individuals would greatly facilitate the genetic analysis of the human immune response to RBC antigens and also provide useful serologic reagents. Technical difficulties inherent in human B-cell immortalization have led to the development of molecular approaches that bypass the need for cell transformation. By cloning human Ig gene segments into bacterial expression vectors, libraries are created of filamentous phage particles displaying Fab fragments on their surfaces. Libraries have been screened with purified, soluble antigen and selected clones genetically manipulated in Escherichia coli to produce soluble Fab fragments. Our goal has been to adapt this technique to the study of RBC autoantibodies and alloantibodies that have specificities against unpurifiable membrane-bound antigens. To test the feasibility of this approach, two sets of phage were created, one set expressing a human anti-Rh(D) Ig and the other expressing a human antitetanus toxoid Ig. After verifying the presence of functional phage-displayed Fabs through biochemical, flow cytometric, and electron microscopic analyses, a model library was constructed comprising one anti-Rh(D)- expressing phage per 10(4) antitetanus toxoid-expressing phage. A method was developed for screening the library with intact Rh(D)- positive RBCs. After four rounds of panning, anti-Rh(D) specificity was enriched more than 10,000-fold to a final frequency of approximately 100%. Plasmid DNA derived from anti-Rh(D) phage was used to produce milligram quantities of soluble recombinant anti-Rh(D) Fabs purified by nitrogen cavitation and nickel-chelation affinity chromatography. The authenticity of the Fabs was confirmed by sodium dodecyl sulfate- polyacrylamide gel electrophoresis and immunoblotting, which showed bands with molecular weights of approximately 50 kD and 26 kD under nonreducing and reducing conditions, respectively. Binding of recombinant anti-Rh(D) Fabs to Rh(D)-positive RBCs was demonstrated by flow cytometry and by an agglutination assay. Our results suggest that repertoire cloning by cell-surface enrichment may have broad application to the study of the human immune response to erythroid antigens in addition to membrane-bound antigens present on other hematopoietic cells.

Recombinant human antibodies: linkage of an Fab fragment from a combinatorial library to an Fc fragment for expression in mammalian cell culture

The combinatorial phage library approach to immunoglobulin repertoire cloning recently made it possible to isolate gene fragments encoding human immunoglobulin G1 Fabs binding with high affinity to specific antigens. Here we describe the construction of genes encoding whole human anti-tetanus toxoid antibodies based on one of these gene fragments and the efficient expression of these constructs by co-transfection of separate heavy and light chain vectors into a Chinese hamster ovary cell line constitutively expressing a viral transactivator protein. This system will be generally useful for the rapid analysis of recombinant antibodies derived from combinatorial libraries.

Interleukin 1, but not Interleukin 1 Inhibitor, is Released from Human Monocytes by Immune Complexes

Immune complexes (IC) are believed to play a role in the pathogenesis of some autoimmune diseases in which interleukin 1 (IL-1) and probably other cytokines also take part. This investigation shows that tetanus toxoid-human anti-tetanus toxoid IC induce human monocytes to release IL-1. The activity was identified as being mainly IL-1 beta by molecular size chromatography, isoelectric focusing, and anti-IL-1 beta affinity chromatography. Endotoxins were eliminated by repetitive washing of the IC suspension and by preincubation of IC with polymyxin B. The IL-1-inducing effect of IC was destroyed by heating at 80 degrees C, and it was not blocked by the cytoskeleton inhibitor cytochalasin B. IL-1 inhibitors were not detected in the supernatants.

Expression of Human Anti-Tetanus Toxoid Antibody in Transfected Murine Myeloma Cells

Mouse-human heterohybridoma cell line, GF4/1.1, secretes a human anti-tetanus toxoid (anti-TT) antibody of the γ3 isotype. This line was used as a source of mRNA for the construction of cDNA libraries and the subsequent isolation of the sequences encoding the human heavy and light chains. Expression vectors containing the cDNAs were constructed and introduced into a non-Ig producing, murine hybridoma cell line, together with a dihy-drofolate reductase (dhfr) selectable marker gene. Transfected cells producing human anti-TT antibody were grown in medium with increasing concentrations of the selecting drug (methotrexate). The level of antibody secretion was tested in cells that had adapted to the higher drug concentration and was found to increase in parallel with increases in the steady-state level of Ig mRNA. This increased productivity was not associated with detectable levels of gene amplification. Stable clones were obtained that secrete levels of human antibody in either open suspension cultures or within microcapsules that compare favorably with those of murine hybridomas.

Crossreactivity and inheritance of idiotypes restricted to human anti-tetanus toxoid antibodies.

The presence of cross-reactive idiotypes on human IgG antibodies of tetanus toxoid (TT) antigen was assessed by examining the capacity of two anti-idiotypic (ID) antisera raised against IgG (Fab')2 anti-TT (idiotype) from two subjects to bind radiolabeled "idiotype" and to inhibit the binding of radiolabeled TT to IgG from unrelated subjects and from family members of the idiotype donors. Idiotypic crossreactivity with unrelated individuals was infrequent and weak but was frequent and stronger among siblings. The strongest idiotypic crossreactivity was seen between identical twins in studies using four anti-ID raised against the anti-TT idiotypes of two sets of twins. The results of the present study suggest that idiotypic determinants restricted to human anti-TT antibodies are, at least in part, encoded by inherited genes, which are infrequently shared among unrelated individuals.

Establishment of hybridomas secreting human monoclonal antibodies against tetanus toxin and hepatitis B virus surface antigen

Mouse-human heterohybrids (M·H) were constructed and compared with other cell lines (human or mouse) as parental cells to obtain hybrids secreting human monoclonal antibody (MoAb). One of the M·H lines, HM-5, was far superior to the others and useful for establishing hybrids secreting human MoAb. Using HM-5 as a parental cell line, we have obtained 2 hybrids secreting human anti-tetanus toxoid MoAb with neutralizing activity and a hybrid secreting human anti-hepatitis B virus surface antigen (HBsAg) MoAb which recognizes the a -determinant of HBsAg.

Human Anti-Tetanus Toxoid Monoclonal Antibody Secreted by EBV-Transformed Human B Cells Fused with Murine Myeloma

An Epstein-Barr virus (EBV)-transformed human B cell line (B6) producing anti-tetanus toxoid (TT) antibody was fused with a nonimmunoglobulin (Ig)-producing murine myeloma and selected in hypoxanthine-aminopterin-thymidine (HAT) medium containing 10(-5) M ouabain. Surviving cells were cloned by limiting dilution and confirmed as hybrids by karyotype analysis and G-11 staining. Hybridomas were stable and secreted 10-fold more anti-TT antibody (IgM kappa) than the human parental cell line. In addition, the hybridomas exhibited a markedly reduced growth requirement for serum (1% fetal calf serum). Since EBV can be used to expand rare antigen-specific B cells in the human, the technique described here may be at present the method of choice for producing human monoclonal antibodies.

The role of complement in the function of the monocyte - macrophage system.

In parallel to the behavior of many agents that activate complement via the alternative pathway and can stimulate macrophages to secrete lysosomal enzymes we investigated the interaction of mouse peritoneal macrophages cultured in a serum-free medium with various stimuli such as zymosan, polyanions, collagen type II, and immune complexes prepared from tetanus toxoid and pooled human anti-tetanus toxoid F(ab)2. All these stimuli induced the release of hydrolytic enzymes from macrophage in culture. The release was time and dose dependent and is not associated with loss of the cytoplasmic enzyme lactate dehydrogenase or any other sign of cell death. The mechanism of macrophage activation by these various agents is unknown. Macrophages have surface receptors for Fc and C3b with the capacity to bind immune complexes or C3b, respectively, and this is followed by activation of the cells. Activation via the Fc part can be excluded in these experiments. The possibility therefore arose that macrophages might be stimulated by endogenous C3 via the C3b receptor, since it is known that all the substances mentioned above can activate C3. To confirm this hypothesis we tried to inhibit this reaction by using an anti-C3-Fab preparation. There was hardly any detectably enzyme release after adding the anti-C3-Fab (dose dependent) together with the various stimuli to the macrophages. An unrelated Fab preparation showed no inhibitory effect. Furthermore, incubation of macrophages and the stimuli together with beta 1H and C3bINA abolished the effect to activate the macrophages. The observations now presented focus attention to the possibility that endogenous C3 could play a role in the stimulation of mouse peritoneal macrophages by various activators of the alternative pathway.

Effect of IgM Fractions with or without Rheumatoid Factor Activity on Antigen‐Antibody Reactions

The effect of isolated IgM fractions, with or without rheumatoid factor (RF) activity, on reactions between human albumin and rabbit anti-human albumin, human IgG and rabbit anti-human IgG, and tetanus toxoid and human anti-tetanus toxoid was assessed in the antigen excess zone. RF-active fractions increased and RF-negative IgM fractions decreased the amount of free antigen. The immune complexes that were affected by RF IgM fractions differed in composition from those affected by normal IgM fractions.

Antigen-specific detection of soluble immune complexes by a solid phase specific antibody system

An antigen-specific immune complex assay based on the following principle has been developed: xenogeneic, antigen-specific antibodies are attached to a solid phase. During first incubation with patient's serum, immune complexes in antigen excess are bound to the xenogeneic antibody by their free antigenic determinants. In a second incubation a labeled antibody, specific for human immunoglobulins, is combined with the antibody part of the immune complex. Quantitation of the label allows the determination of the immune complexes. The principle of the method has been varied using artificial soluble immune complexes of tetanus toxoid and human anti-tetanus toxoid antibody, and immune complexes prepared by mixing patient sera containing either HBsAg or anti-HBsAg antibodies. The reliability of the results is shown by their coefficient of variation (2.5%). With the method described soluble immune complexes predominantly in slight antigen excess, which are thought to be responsible for development of immune complex disease, have been detected.

Skin Sensitizing Antibodies: A Comparative Study of Canine and Human PK and PCA Antibodies and a Canine Myeloma Protein

Summary Canine reaginic antibody from 13 atopic animals with hypersensitivity to ragweed pollens has been separated from other canine immunoglobulins, including the γM-globulins, a canine polymeric (10 S) myeloma protein and a canine γG-antibody eliciting a passive cutaneous anaphylactic (PCA) reaction in the guinea pig, by Sephadex G 200 gel filtration and sucrose density gradient ultracentrifugation. The canine reaginic antibody also has been compared with atopic human reaginic antibody, human isohemagglutinins with intermediate sedimentation coefficients, human anti-tetanus toxoid (PCA) antibody and pathologic human immunoglobulins, and has been found to be closely similar in size to the human reaginic antibody. The ability of canine reaginic antisera to elicit a dermal anaphylactic Prausnitz-Küstner reaction was markedly reduced after exposure to 2-mercaptoethanol.