Search

The site of interaction for concanavalin A (Con-A)-induced histamine release from human basophils was studied in vitro. Blocking the epsilon-one determinant (D→ 1) of IgE with high concentrations of monomer (Fab) anti-Dε,1 does not significantly inhibit the quantity of histamine released by suboptimum concentrations of Fc specific anti-IgE. This indicates that the monomer anti-Dε1 does not have the capacity to sterically hinder the bridging of all of the determinants in the Cε3 and Cε4 domains (Fc′-ε′Eregion) of IgE. The monomer anti-Dε1 does effectively inhibit release induced by suboptimum concentrations of Con-A. The data indicate that for suboptimum concentrations, Con-A activation is IgE mediated and takes place in the proximity of Dε1 and not at the membrane receptor for IgE. [ABSTRACT FROM AUTHOR]

The peptic fragments F(ab')2 and Fc" of human polyclonal IgE were tested by the SpA-IgE radioimmunoassay for interaction with protein A from Staphylococcus aureus. The Fab'2∊ fragment but not the Fc"∊ fragment retained the ability to react with protein A. IgG preparations from different species were tested for their capacity to inhibit the reaction between 125I-IgE and protein A. IgG preparations from man and the dog, pig, guinea-pig and rhesus monkey were all potent inhibitors whereas those from the rabbit, rat, sheep, horse, cow, goat and mouse were very poor inhibitors. The inhibition of the binding of 125I-IgE to protein A by Fab'2γ fragments, but not by fcγ fragments, suggests a novel type of interaction of protein A with immunoglobulins. [ABSTRACT FROM AUTHOR]

An assay, the paper radioallergosorbent test (PRAST), for the measurement of specific serum IgE antibody in the ral is described in detail. This assay has been used, in conjunction with a modified PRAST for the determination of relative specific serum IgG antibody and the PRIST assay for total serum IgE [13], lo measure specific IgG and IgG and total IgE immune responses in normal parasite infected rats immunized using various protocols. The results indicate that there is a relationship between the basic IgE level and the immune response, i,e. a rat strain with a low constitutive IgE level demonstrates a weak response whereas a high level strain reacts strongly. When PRAST and passive cutaneous anaphylaxis (PCA) were compared, using standardized IgE antibody containing sera, the results were in good agreement. However, PRAST is the preferable assay as it shows less intrinsic variation, is more sensitive than PCA, and is not influenced by high serum IgE levels in the recipient animal. [ABSTRACT FROM AUTHOR]

An assay the paper radioimmunosorbent test (PRIST) for the measurement of total serum IgE in the rat, that allows the measurement of IgE down to a level of 0.25 ng/ml, is described. With this assay it has been demonstrated that significant differences exist in normal serum IgE levels in non-immunized rats. These differences are strain-dependent. and strains may be classified as to low (<50 ng/ml), medium (50-300 ng/ml) or high (>300 ng/ml) serum levels. The serum IgE level is not sex-dependent. Environmental factors have a pronounced influence, optimal housing conditions resulting in low and stable levels while suboptimal conditions result in high levels with great fluctuations. Hybridization experiments suggest a multigenic control, with low IgE strains having a dominating suppressor effect. [ABSTRACT FROM AUTHOR]

The complete primary structure of allergen M of cod (Gadus cattarias L.) is presented. The amino acid sequence of fragment TM1, the NH2-terminal peptide of allergen M, was elucidated by the dansyl-Edman method. It consists of 75 amino acids and 1 glucose residue (mol, wt, 8,492), By summation of the sequence data of fragment TM1 and the previously reported fragment TM2, the intact allergen M has 113 residues (mol.wt, 12,328), Fragment TM1 of cod shows less homology (30.6%) with the corresponding fragments of other reported fish species than does fragment TM2 (42.1%); the intact allergen M shows 34.5% homology. The single half cystine of allergen M was shown to be blocked. Gas chromatographic analysis of the reduced and nonreduced allergen M suggested that the glucose is bound to Cys 18 through an S-glucosidic bond, [ABSTRACT FROM AUTHOR]

The amino acid sequence of the COOH-terminal fragment TM2 of cod allergen M has been determined by the dansyl-Edman procedure. The fragment consists of 38 residues (mol. wt. 3,854), and the sequence shows great homology with the sequence of the corresponding fragment of white muscle albumin from carp, hake, and pile. Unique for the TM2 (and allergen M) from cod is the presence of a tryptophyl residue at position 5 from the COOH-terminal end. [ABSTRACT FROM AUTHOR]

Amino acid composition, end-group analysis, and antigenic analysis have been performed on isolated pFc′ fragments (Cγ3 homology region) from the major allotypic variants of human IgG. A comparison of the amino acid composition of Gm(a+x+) and Gm(a+x+) pFc′ fragments showed less serine and more glycine in the Gm(a+x+) proteins. Two IgG2 pFc′ fragments were shown to resemble IgG1 Gm(f) pFc′ fragments in their amino acid compositions, except that there was more threonine and less alanine in the IgG2 fragments. This was also observed in two IgG3 Gm(g) proteins and may be the basis for the expression of a non b antigen. IgG3 fragments of both Gm(g) and Gm(b) allotypes showed six amino acid differences from the IgG1 subclass. There was more arginine, serine, and isoleucine and less histidine, lysine, and valine in both allotypes. In addition, analysis of a single Gm(b) pFc′ fragment showed differences from the Gm(g) proteins; there was more phenylalanine, alanine, and proline and less tyrosine, threonine, and, possibly, aspartic acid. [ABSTRACT FROM AUTHOR]

In Hooded Lister rats the primary IgE antibody response induced by immunization with antigen and adjuvant may be enhanced either specifically by a further dose of antigen (booster response) or non-specifically by infection with helminth parasites (potentiated response). The initial immunizing technique can influence the occurrence and level of these enhanced responses and here we describe the effect of using different adjuvants in the priming event. Although the level of the primary response was broadly similar following immunization with egg-albumin and the adjuvants Bordetella pertussis aluminium hydroxide or Freund's complete adjuvant, the booster response was inhibited and the potentiated response intensified in animals immunized with the latter two adjuvants. A significant IgE booster response could only be obtained if B. pertussis had been used in the initial immunization. When aluminium hydroxide was adsorbed to B. pertussis it was found to have the same inhibitory effect on subsequent booster responses as when it was adsorbed to antigen. These results are discussed in relation to the intricacies of IgE production in the present model and to more general mechanisms of adjuvant action. [ABSTRACT FROM AUTHOR]

Purified human alpha-foetoprotein (AFP) isolated from extracts of foetal and hepatoma tissues, and from cord serum was evaluated as to its suppressive effects on in vitro lymphocyte responses to stimuli which selectively trigger human B or T cells. The effects of equivalent concentrations of individual AFP preparations were compared on lymphocyte cultures stimulated with the human B cell mitogen Staphylococcus aureus strain Cowan I organisms, with the T cell mitogen phytohaemagglutinin (PHA), and with irradiated allogeneic lymphocytes in the one-way mixed lymphocyte reaction (MLR). PHA responses were significantly inhibited by most purified preparations of AFP in a dose-dependent manner, within the concentration range of 300 to 18 μg/ml, However, individual foetal-derived AFP preparations did vary in suppressive potency on PHA responses, and attempts to reactivate an inactive AFP were unsuccessful. In parallel cultures the mitogenic response to protein A expressing Staph, aureus bacteria was normal or even slightly enhanced by AFP. The one-way MLR was effectively suppressed at higher concentrations of AFP (300-600 μg/ml) than were required for inhibition of PHA responses. The inhibitory effect of AFP on PHA induced lymphocyte proliferation was not altered by increases in the mitogen dose. No evidence was found that AFP merely inhibits PHA responses by direct interference with mitogen or by competition for cell surface receptors with the mitogen. The results reported here indicate that human AFP effectively suppresses certain T cell-mediated reactions, but not B cell responses in vitro, and these are in line with previously reported findings in the murine AFP system. [ABSTRACT FROM AUTHOR]

The techniques of starch gel electrophoresis, immunoelectrophoresis and high resolution gel filtration have been used to investigate the peptic cleavage or human G-Myeloma proteins of the four known subclasses. The appearance and fate of F(ab')2 and pFc' fragments and the persistence of undegraded IgG have been contrasted and distinctive patterns of pepsin sensitivity have been established for each subclass. The IgG 1 subclass is the most resistant and is degraded by pepsin in a manner which is closely similar to that observed for pooled IgG. IgG 2 molecules are also relatively resistant to peptic cleavage whereas IgG 3 and IgG 4 proteins are much more sensitive. Nevertheless all the subclasses are cleaved by the enzyme in similar susceptible regions and give rise at some stage to the same products: F(ab')2 fragment, pFc' fragment and peptides from the N-terminal half of the Fc region. [ABSTRACT FROM AUTHOR]

Immunochemical comparisons have been made of the F(ab')2 and the pFc' fragments of each of the four subclasses of human IgG. The F(ab')2 fragments of IgG 3 proteins were found to exhibit anomalous gel-filtration behaviour compared with similar fragments from the other subclasses. This difference was unrelated to carbohydrate content and may indicate a unique conformation for IgG 3 molecules. The pFc' fragments of all four subclasses were similar in size and antigenically indistinguishable by gel-diffusion tests but on both starch gel electrophoresis and immunoelectrophoresis the IgG 4 pFc' fragment was of faster mobility. Some minor products of pepsin digestion arising From the IgG 2, IgG 3 and IgG 4 subclasses were also investigated. These fragments were derived from the Fab regions of the respective parent molecules. [ABSTRACT FROM AUTHOR]

Two IgEL and one IgGK producing cell lines have been established in vitro from peripheral blood and bone marrow of an E myeloma patient. Morphologic and immunologic studies indicate that cells of the IgE producing lines are derived from the same clone of myeloma cells which grew in vivo. They have remained essentially unaltered with a stable near-diploid karyotype and continuous production of intact IgE molecules during 18 months in culture. The IgGK producing line has all the characteristics ascribed to permanent lymphoblastoid lines, and is considered to be of non-malignant lymphoid origin. The process of establishment is described and it is suggested that lymphoblastoid cells have a selective advantage over myeloma cells. Permanent myeloma cell lines can therefore probably be obtained only if cells capable of forming established lymphoblastoid lines are very few or absent in the original biopsy. The establishment of a permanent cell line continuously producing intact molecules of IgE should permit further studies on the biological role of this class of immunoglobulins. [ABSTRACT FROM AUTHOR]

Diagnosis of atopic diseases can sometimes present difficulties. IgE estimation in serum can obviously be of value in these cases. However, on evaluating the results consideration must be taken of several different factors which may be of importance with regard to the levels of this immunoglobulin, Some of these are discussed here. Patients with asthma and atopic eczema have raised IgE levels more often than patients with hay fever. In the latter cases a significant increase in the IgE level is found during the pollination season. Dust and mould seem to be weak allergens which seldom give rise to elevated IgE levels. Specific hyposensitizaion significantly increased the IgE levels during the first 3 weeks of treatment. Steroids, cytostatics and disodium cromoglycate do not seem to influence the IgE concentrations nor do bacterial or viral infections, Markedly increased IgE concentrations were found in patients with parasitic infestations; Ascaris lumbricoides is one of the parasites of current interest. [ABSTRACT FROM AUTHOR]

A new class of normal immunoglobulin corresponding to a myeloma protein (myeloma-IgND), which fails to react with specific antisera to IgA, D, G and M (Johansson and Bennich, 1967) was detected in serum from sixty-two blood donors using a radio-immunosorbent technique (Wide and Porath, 1966) IgND in normal sera corresponds to myeloma-IgND on electrophoresis, gel filtration and DEAE-chromatography. Isolated IgND gave a reaction of identity with myeloma-IgND in Ouchterlony gel diffusion analysis. The concentrations of IgND in 93 5 per cent of the samples was within the range of 100–700 ng/mL. Normal levels of IgND were found in four samples apparently lacking IgA and/or IgD as determined by single radial immunodiffusion. Elevated levels of IgND were found in four samples one of which was from a subject with previously undiagnosed extrinsic asthma. It is concluded that myeloma-IgND represents a new class of human immunoglobulin.

An 8S myeloma component, isolated from serum of a patient with myelomatosis is described, which appears to have no antigenic determinants in common with human α-, δ-, γ- or μ-polypeptide chains as revealed by immuno-electrophoresis and Ouchterlony gel diffusion analysis. The myeloma protein migrates in the fast γ-region on electrophoresis at pH 8·6 and has an elution volume on Sephadex G-200 similar to that of 6·5S IgA. The isolated myeloma component has an approximate molecular weight of 200,000 and a total carbohydrate content of 10·7 per cent. Reduction with β-mercaptoethanol and acid dissociation yields light polypeptide chains of Type L and a carbohydrate-rich component, in the ratio of 1:4. Antisera specific to determinants on the heavy chains of the myeloma protein showed no reaction with the immunoglobulins A, D, G or M. Instead unique determinants were found on the heavy polypeptide chains. [ABSTRACT FROM AUTHOR]

Subfragments of the pFc' fragment (equivalent to the Cγ3 homology region) of human IgG have been obtained by tryptic and chymotryptic digestion, Tryptic digestion for 4 or 8 hours removed N-terminal peptides of 5 and 7 amino acid residues respectively. Chymotryptic digestion appeared to remove an N-terminal pentapeptide and also approximately 14 residues from the C-terminus. However, chymotryptic cleavage in the presence of trypsin inhibitor removed the C-terminal peptide and only 2 N-terminal residues. Haemagglutination-inhibition tests for Gm activity indicated that both of the tryptic fragments retained Gm(a), (x), (b°), and 'non a' activities. In contrast, the chymotryptic fragments lacked Gm(a), (x), and 'non a' activities, but retained Gm (b°) activity. These results support our earlier hypothesis that certain C-terminal amino acids of the γ-chain are essential for the serological expression of Gm(a) and 'non a' markers. [ABSTRACT FROM AUTHOR]

The article reports that it was possible to detect in the sera of patients, for whom visceral larva migrans had been confirmed histologically, not only antibodies to the excretory-secretory antigens of Toxocara canis by means of fluorescence techniques, but also specific homocytotropic antibody measured by passive cutaneous anaphylactic tests in baboons and monkeys. There is ample evidence that the basis for making a diagnosis of visceral larva migrans requires further investigation, and that the problem, as with the immunodiagnosis of all nematodiases depends ideally on the isolation and detection of a species specific nematode antigen/allergen to demonstrate the presence of correspondingly specific antibody.