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At least 19 recordsLinked to original sources
PubMed1976

[FAB immunoglobulin fragments. I. The comparative characteristics of the serological and virus-neutralizing properties of a gamma globulin against tick-borne encephalitis and of the FAB fragments isolated from it].

A comparative study was made of the serological properties and virus-neutralizing activity of antiencephalitis gamma-globulin and Fab-fragments isolated from it by gel-filtration. Horse immunoglobulins against the autumno-summer tick-borne encephalitis virus could be disintegrated with the aid of papaine to monovalent Fab-fragments which (according to the complement fixation reaction, the test of suppression of the complement fixation, and the HAIT) retained the serological activity whose level was compared with that of the serological activity of gamma-globulin. Fab-fragments possessed a marked virus-neutralizing activity. The mean value of a logarithm of the neutralization index was 2.65 +/- 0.2 for Fab-fragments and 3.74 +/- 0.38 for gamma-globulin (P less than 0.01).

Animals↗
PubMed1977

[Immunoglobulin FAB-fragments: specific activity and reactogenicity. III. Comparative study of the antigenic properties of anti-encephalitic gamma-globulin and FAB-fragments isolated from it].

Parenteral administration of antiencephalytic gamma-globulin and of the Fab-fragments, extracted from it, to rabbits stimulated the formation of specific antibodies. The maximal blood serum specific antibody level in rabbits reimmunized with Fab-fragments was much lower than that following the reimmunization of rabbits with gamma-globulin. Antibodies specific to gamma-globulin and Fab-fragments were concentrated in the gamma-globulin fraction of the immune sera and could be referred to the immunoglobulins of G class.

Animals↗
PubMed1979

An enzyme immunoassay for the measurement of thyroglobulin in human serum.

An enzyme-linked sandwich immunoassay using silicone rods coated with rabbit (anti-human thyroglobulin) immunoglobulin G and rabbit (anti-human thyroglobulin) monovalent fragment of immunoglobulin F (Fab') conjugated with beta-D-galactosidase was developed for the measurement of thyroglobulin in human serum. The volume of serum needed for the assay was as little as 2 microliters. The sensitivity of the assay was 3.5 ng/ml, which is equal to or rather higher than that of radioimmunoassay. The specificity of the assay was demonstrated by the following observations: (1) The absence of crossreaction of thyroxine and triiodothyronine, (2) non-detectability of thyroglobulin in the sera of patients who underwent total thyroidectomy, (3) parallelism of the standard curve with dilutions of reference serum. The precision of the assay was proven by the demonstration of the sufficient recovery of human thyroglobulin added to sera (92--99%) and coefficients of variance in within and between assays were 6.2--9.3 and 2.5--5.3%, respectively. Furthermore, a highly significant correlation was observed between thyroglobulin concentrations measured by our enzyme immunoassay and those by radioimmunoassay (r = 0.99, p less than 0.001, n = 63). Human thyroglobulin in serum was detectable in 90% of 146 normal subjects, the concentration (mean +/- S.D.) being 13.3 +/- 10.3 ng/ml.

Female↗
PubMedDate not supplied

[Effect of perturbing agents on the dynamic properties of immunoglobulin fragments].

The effect of NaCl, (NH4)2SO4, sodium dodecylsulphate and temperature on conformational properties of light-chain dimers and the Fab-fragments of immunoglobulins G has been investigated using the spin-label method. All these agents despite their different nature, induce qualitatively the same shift in the equilibrium between the A- and B-states of spin label towards the state of higher microviscosity A. The effect of 1.2 M NaCl and 0.75 M (NH4)2SO4 increase the stability of IgG in relation to temperature, as a result of this shift. The data obtained are interpreted in terms of the dynamic model of protein behaviour in water suggested earlier. In accordance with the model the action of the agents perturbing the conformation of protein and the ordered structure of water in the non-polar cavities of protein, reduce the life-time of this cavities in the water accessible state.

Ammonium Sulfate↗
PubMed1979

[Structural and immunochemical studies of carp (Cyprinus carpio L.) immunoglobulin. V. Tryptic fragments of carp (Cyprinus carpio L.) immunoglobulin M].

Carp IgM, isolated from normal serum is more sensitive to trypsinization compared to a human myeloma protein IgMGo. Under the same conditions (treatment with trypsin at 56 degrees C for 30 min) carp IgM was degraded to small, mostly dialysable peptides to a larger extent than IgMGo. In both cases the fragmentation resulted in immunoelectrophoretically pure Fab mu and Fc mu fragments. The Fab mu fragments of human IgM (yield: 20% of used IgM material) had a molecular weight of 54,000, the Fc mu fragments (yield: 30%) were a heterogenous mixture as far as molecular sizes concerned with values of about 300,000. For the corresponding fragments of carp IgM we could analyze a molecular weight of about 43,000 for Fab mu (yield: 8%) and for Fc mu (yield 10%) three fractions of 160,000, 130,000 and 90,000. The reductive subunits of Fc mu fragments showed different molecular weights: 39,000 for IgMGo and 45,000 for carp IgM. The anti-fragment antisera prepared in rabbits were monospecific as demonstrated by immunodiffusion.

Animals↗
PubMed1978

Demonstration of antibody for glutamic pyruvic transaminase (GPT) in chronic hepatic disorders.

The present paper describes the detection of an autoantibody for glutamic pyruvic transaminase (GPT) in sera of patients with chronic hepatic disorders. In 16 out of 500 patients, the existence of an antibody for pig GPT was demonstrated by the double antibody method, gel filtration and radioimmunoelectrophoresis. The antibody was demonstrated as an immunoglobulin G (IgG) with either polyclonal or monoclonal type (kappa or lambda). The binding portion of IgG with GPT was determined as the fragment Fab, but not Fc of IgG. Because the binding of 125I-pig GPT with the patient's antibody was displaced by human GPT, this antibody may have the characteristic of cross reacting with both pig and human GPT. Although the mechanism of production of the antibody for GPT and the pathological significance of the antibody in chronic hepatic disorders remained obscure, possible inhibition of GPT activity in serum is suggested in the presence of this antibody.

Alanine Transaminase↗
PubMed1977

[Comparative analysis of the adjuvant action of fab-fragments of normal rabbit IgG obtained using pepsin and papain].

The capacity of Fab fragments of normal rabbit IgG to enhance the immune response to sheep erythrocytes in the homologous recipients was determined by the structure of the C-terminal part of the heavy chain Fd fragment. This followed from the fact that pepsin F(a')2 and Fab' fragments enhanced considerably the hemagglutinin production and proliferation of the antibody-forming cells in the spleen, whereas papain Fab fragments, used in the same dose as the pepsin fragments, possessed only negligible adjuvant activity. As shown the adjuvant activity of pepsin and papain fragments displayed an inverse correlation with the titres and papain homoreactants in the sera of the homologous recipients. The data obtained suggested that the target cells for Fab fragments were lymphocytes carrying cytophilic homoreactants as receptors for the fragments.

Adjuvants, Immunologic↗
PubMed1978

Protein A reactivity of whole rabbit IgG and of fragments of rabbit IgG.

Approximately 15 per cent of the total IgG in normal rabbit serum reacted with protein A. When this protein reactive IgG fraction was treated with acid at pH 2.7 and then digested with plasmin, thus splitting the rabbit IgG between the CH2 and CH3 domains, both the isolated Facb and the pFc' fragments were protein A non-reactive. This results indicates that at least one intact Fc chain is necessary to fulfil the protein A-fc interaction. Traces of protein A reactive rabbit F(ab')2 fragments isolated from normal IgG were also found. These fragments mixed with normal rabbit IgG precipitated protein A.

Animals↗
PubMed1979

[Isolation of FAB and Fc fragments from murine immunoglobulin G1].

Two methods of isolating Fab- and Fc-fragments from mouse immunoglobulin G1 are presented. The first method involves fractionation of papain protein hydrolysate on a column with DEAE- (or DE-32)-cellulose adjusted with 0.005 M K-phosphate buffer, pH 8. The Fab-fragment was eluted from the column with the starting buffer. The Fc-fragment was eluted, with the buffer ionic strength being increased to 0.4 M. Another method involves protein fractionation on an ion exchanger adjusted with 0.004 M Tris-H3PO4 buffer, pH 8.5. All the protein was column bound. The Fab-fragment was eluted with 0.04 M Tris-buffer containing a 0.004 M mixture of K-phosphates, pH 8.6. The Fc-fragment was eluted, with ionic strength being raised to 0.4 M with phosphates. As none of the methods assures isolation of absolutely pure Fab- or Fc-fragments, it is requird that cross absorption of antisera with respective immunosorbents may be carried on in order to obtain monospecific antisera to these fragments.

Animals↗
PubMed1977

The incomplete anti-Rh antibody agglutination mechanism of trypsinized ORh+ red cells.

The capacity for binding to trypsinized and non-trypsinized ORh+ red cells, of the IgG incomplete anti-Rh antibody and its F(ab')2 and Fc fragments has been investigated. An analysis has also been made of the capacity of non-specific human IgG, aggregated non-specific human IgG, human IgM (19S) and IgM (7S), and of fragments Fcgamma, Fcmu and Fc5mu to inhibit the agglutination of trypsinized ORh+ red cells by the IgG incomplete anti-Rh antibody. The results obtained indicate that these antibodies behave in a similar manner to that of nonprecipitating antibodies, and that the agglutination of trypsinized red cells seems to be a mixed reaction due to the interaction of an Fab fragment with its Rh antigenic determinant present in the surface of a red cell and the Fc of the same molecule with a receptor for Fc present in adjacent red cells. The trypsin treatment apparently results in the liberation of occult Fc receptors. It has also been demonstrated that in the agglutination of ORh+ red cells by IgG incomplete anti-Rh antibody in the presence of albumin, interaction must occur in some manner between the albumin and the Fc fragment since the F(ab')2 fragment does not give rise to agglutination under such conditions.

ABO Blood-Group System↗
PubMed1978

Isolation of enzymatically derived fragments of guinea pig IgG and an examination of their reactivity against Staphylococcal protein A.

Papain digest of guinea pig IgG2 was separated by ion-exchange chromatography into five fractions, one containing mainly Fab and four Fc fractions. Covalently linked Fc (cFc) and non-covalently linked Fc fragments (nFc) were present, both with a molecular weight (Mw) of about 56,000. nFc was split into half fragments by gel filtration under dissociating condition (Mw 25,000 to 27,000). An incomplete Fc fragment (iFc) was also isolated (Mw 36,000), which consisted of a Fc chain (Mw 26,000) non-covalently linked to a piece of another chain. These preparations all reacted with protein A. In addition, the Fc' fragment (Mw 22,000), which is the C-terminus of the Fc fragment, was isolated. This fragment did not react with protein A. The cFc was treated with acid and then digested with trypsin at pH 7.8 for 45 s. The digest were separated into four fractions (I-IV) by gel filtration on Sephadex G-100. Fraction I was indistinguishable from intact Fc, fraction II contained an incomplete covalent Fc fragment (Mw 34,000 to 38,000). Both these fragments reacted with protein A. Fraction IV consisted of fragments belonging to the C-terminus, and was protein A non-reactive. Fraction III was shown to contain a mixture of fragments belonging to fractions II and IV.

Animals↗
PubMed1977

Three-dimensional structure of an intact human immunoglobulin.

We have examined the low-resolution structure of a complete human IgG1 using known domain coordinates from crystallographic investigations of immunoglobulin fragment structures. Our results indicate that the Fc portion of this molecule has a structure similar to that of an isolated Fc fragment, with the carbohydrate moiety playing a central role as the principal contact between the CH2 domains. Carbohydrate also forms a large part of the interface between the Fc and Fab regions. The relative orientations of the variable and constant portions of the Fab regions are intermediate between those reported previously, emphasizing the flexibility of the switch region. These data do not support a two-state allosteric model such as has been proposed for antibody effector functions.

Carbohydrates↗
PubMed1975

Further studies on the biologic properties of guinea pig IgG1 antibodies. II. In vivo activation of C3 by anti-glomerular basement membrane antibodies.

Normal rats were injected with guinea pig anti-rat glomerular basement membrane antibodies of the IgG1 or IgG2 class or with their F (ab') 2 fragments, in order to study which antibody site triggers the alternate complement pathway in vivo. Both IgG classes were able to induce a heavy proteinuria and led to C3 deposition in the glomeruli in a pattern similar to their own distribution along the glomerular basement membrane, as shown by the immunofluorescence technique. The Fab(ab')2 fragment of IgG2 did not produce C3 binding or proteinuria. The F(ab')2 fragment of IgG1 was difficult to obtain devoid of Fc determinants. A F(ab')2 fragment of IgG1 still bearing Fc determinants led to C3 binding and proteinuria, whereas the true F(ab')2 fragment of IgG1 had none of these effects in two out of three animals.

Animals↗