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J Radl

Publications and source records attributed to J Radl.

At least 73 records · Page 4Linked to original sources
PubMed1988

Dot-immunobinding assay as an accurate and versatile technique for the quantification of human IgG subclasses.

A dot-immunobinding assay on nitrocellulose membranes has been developed for the quantification of human IgG subclasses using subclass-specific monoclonal antibodies. The advantages of this technique can be summarized as follows: (1) possibility of rapid semi-quantitative evaluation and/or precise quantitation from the same dot-pattern; (2) simple procedure with very good reproducibility; (3) sensitivity for nanogram concentrations of individual subclasses, therefore applicable not only to serum but also to other body fluids with a low content of IgG; (4) very small amounts of test material needed; (5) very good correlation of results with other techniques (ELISA, radial immunodiffusion) but without some of the inherent problems of the latter methods.

Antibodies, Monoclonal↗
PubMed1988

IgG subclass distribution in juvenile human tonsil: IgG3 and IgG4 results of specific antibody production using synthetic peptides.

A decapeptide with a sequence corresponding to a part of the hinge region of human IgG3 was used to prepare a mouse monoclonal antibody (Mab 330-2.2). The Mab recognized IgG3 in ELISA only when the IgG3 was denatured by mild heat. Mab specificity in immunohistochemistry was calibrated with a number of reference Mabs obtained through a WHO/IUIS collaborative study. Finally, Mab 330-2.2 was used in conjunction with a set of other isotype specific Mabs to study the (sub)class distribution of cytoplasmic Ig containing cells in palatine tonsil. IgG3 within the IgG class was strongly over-represented in our tonsil material if compared to the representation of IgG3 in serum.

Antibodies, Monoclonal↗
PubMed1988

The influence of T cells on homogeneous immunoglobulins in sera of athymic nude mice during aging.

In this study, results are presented which are in agreement with predictions made on basis of the 'three-stage hypothesis' on the development of benign monoclonal gammapathy (BMG). In a T-cell depletion model. C57BL/Ka nude mice were shown to develop single and multiple homogeneous immunoglobulins (H-Ig) during aging in the highest frequencies known so far. Ninety per cent of the C57BL/Ka nude mice displayed one or more H-Ig at 12 months of age. In a T-cell supplementation model, infusion of corticosteriod resistant T cells into 9-month-old BALB/c nude mice resulted in a decrease in the frequency of H-Ig from 43% at 9 months down to 20% at 15 months of age. In contrast, the frequency of H-Ig in the control group increased from 40% at 9 months up to 68% at 12 months. The results show that normally functioning T cells are essential for the generation of a normal, heterogeneous Ig spectrum; they further support the validity of the three-stage hypothesis with regard to the role of an impairment of the T immune system in the pathogenesis of BMG.

Aging↗
PubMed1988

Influence of long-term antigenic stimulation started in young C57BL mice on the development of age-related monoclonal gammapathies.

Long-term antigenic stimulation by multiple antigens (DNP conjugated to human serum albumin (DNP-HSA), ovalbumin and pneumococcal polysaccharide) without adjuvant in young C57BL mice resulted in the development of homogeneous immunoglobulins (H-Ig) during aging in frequencies higher than those in the control group. Our data showed that antigen-specific B-cell clones were at least in part responsible for this increased incidence of age-related monoclonal gammapathies (MG). Using in situ adsorption performed on Wieme's agar plates and in immunoelectrophoresis, antibody activity to one of the immunizing agents (DNP-HSA) could be demonstrated within 10% of the in old mice appearing H-Ig components. This frequency was significantly different from the 0.3% of the H-Ig components of the aging control mice. The antigen-specific MG belonged most likely to the category of benign MG. These findings indicate that long-lasting antigenic stimulation contributes to the development of age-related B-cell proliferative disorders, namely of the benign MG.

Aging↗
PubMed1988

Transient increase of serum IgD levels after allogeneic bone-marrow transplantation.

Serum IgD levels were followed longitudinally twice a week for up to 100 days in 60 children undergoing allogeneic bone-marrow transplantation (n = 52) or immunosuppression (n = 8) for the treatment of leukaemia, severe aplastic anaemia or severe combined immunodeficiency. In 40 out of the 49 post-transplantation periods analysed (82%), a transient sharp increase of serum IgD was detected, irrespective of initial disease. A similar peak was found in one out of five children after immunosuppressive treatment. A second IgD peak was only recorded in grafted patients (14/49 post-transfusion periods). Peak levels of IgD ranged from 1.3 to 185.7 IU/ml (median 12.2 IU/ml), which represents a 2.6 to 22.4-fold increase over 'baseline' levels. In the transplanted leukaemia and aplastic anaemia patients, the rise of serum IgD occurred at the same time (geometric mean 16 days after transplantation) and was shown to represent heterogeneous polyclonal IgD in six of them. The onset of the serum IgD peak was significantly delayed in children suffering from severe combined immunodeficiency (P less than 0.05) and was demonstrated in one patient to consist of homogeneous IgD. No relation was found between either the occurrence of clinical acute graft-versus-host disease or infections after treatment, and the time of onset of IgD elevations. To detect transient serum IgD peaks as described here, frequent sampling of sera is necessary. The origin of the early IgD peaks seems to reside within the recipient's cells by an unknown mechanism. The late IgD peaks are most probably an expression of gradual reconstitution of the immune system following bone-marrow transplantation.

Adolescent↗
PubMed1988

Immunoblotting with (sub)class-specific antibodies reveals a high frequency of monoclonal gammopathies in persons thought to be immunodeficient.

Immunoblotting, in combination with high-resolution electrophoresis and the use of mouse monoclonal antibodies to human (sub)class immunoglobulin (Ig) isotypes, substantially increased the sensitivity with which homogeneous Ig components (H-Ig) could be detected. Using this technique, we reinvestigated 40 selected sera, previously found to be negative for H-Ig by agar electrophoresis and immunofixation, from two groups of individuals thought to have an age-related immunodeficiency, i.e., persons older than 95 years and recipients of kidney grafts who were undergoing immunosuppressive treatment. In both groups, small single or multiple H-Ig components were found, in frequencies of 76% and 79%, respectively. For comparison, the Ig spectrum of 10 sera from patients on dialysis treatment and of 33 sera from young adult blood donors was ordinarily heterogeneous, except for one elderly patient and one blood donor with a previously unknown IgG2 deficiency. These results are complementary to the observations in some immunodeficiencies in children and indicate that the appearance of single or multiple H-Ig components in low concentration can be considered a very sensitive indicator of certain immune system disorders forming a separate category of monoclonal gammopathies.

Adult↗
PubMed1988

The influence of genetic factors associated with the immunoglobulin heavy chain locus on the development of benign monoclonal gammapathy in ageing IgH-congenic mice.

The role of genetic factors associated with the immunoglobulin heavy chain locus (Igh) in the development of benign monoclonal gammapathy (BMG), a benign B-cell proliferative disorder, was investigated in six Igh congenic mouse strains during ageing. The strains used had a C57BL or BALB background: C57BL/6, BALB.Igb and CB-20 carrying the C57BL Igh (Ighb allotype), BALB/c and C57BL/6.Iga carrying the BALB/c Igh (Igha allotype) and BAB-14, that is of BALB/c origin with the exception of the constant part of the Igh, which is of C57BL origin. The frequency of homogeneous immunoglobulins (H-Ig), both single and multiple, was the highest in C57BL/6 mice, followed by C57BL/6.Iga. The frequencies of H-Ig in BALB.Igb and CB-20 mice were higher than those of BALB/c and BAB-14, although somewhat lower than in C57BL/6.Iga mice. Multiple H-Ig were found especially in the sera of C57BL/6 mice. Categorization of the monoclonal gammapathies (MG) on the basis of their origin showed a single transient monoclonal B-cell proliferation in 0-8% of the mice of all strains. Persistent, non-progressive MG, presumably BMG, were detected in 64% of C57BL/6, 30% of C57BL/6.Iga, 22% of BALB.Igb, 17% of CB-20, 13% of BAB-14 and 6% of BALB/c mice. Multiple myeloma or Waldenström-like B-cell lymphoma were found to be responsible for 2-4% of the paraproteinemias in all strains. The remaining H-Ig, varying from 11% of the C57BL/6 to 70% of the BAB-14 mice, could not be evaluated in time. The most frequent isotypes of the BMG within C57BL/6 and C57BL/6.Iga were IgG2a and IgG2b, respectively; IgM was the most frequent isotype within the four BALB congenic strains. The immunoglobulin heavy chain allotypes under investigation appeared to be only partly related to the onset, occurrence, multiplicity and persistence of the BMG developing in these Igh congenic C57BL and BALB strains during ageing. The immunoglobulin heavy chain allotypes, however, were not related to the major isotype of the BMG. The results obtained in CB-20 and BALB.Igb on the one hand, and in BAB-14 on the other hand, may suggest a role for the variable part of the Igh in the development of BMG. Since no absolute influence could be ascribed to the Igh, we assume that primarily other genetic sequences regulating proliferative B-cell functions account for the pathogenesis of BMG.

Aging↗
PubMed1988

Serum levels and in vitro production of IgA subclasses in patients with primary IgA nephropathy.

Patients with primary IgA nephropathy have deposits of IgA1 in their kidneys, and increased plasma levels of macromolecular IgA1. Total serum IgA concentrations are frequently elevated, but studies on the subclass distribution have been few and conflicting. Several investigators found that production of IgA by peripheral blood lymphocytes in culture is increased. However, the distribution of the IgA subclasses produced has not been studied previously. We studied the serum IgA subclasses in 14 patients with IgA nephropathy, and found a significant (P less than 0.001) increase in IgA1 (3.71 +/- 1.34 mg/ml, mean +/- s.d.) compared with controls (1.77 +/- 1.10 mg/ml). Serum IgA2 was not different in patients and controls. The ratio of serum IgA1 to total IgA was also significantly (P less than 0.001) higher in patients (92.2 +/- 4.9%) than in controls (80.2 +/- 6.6%). Studies of immunoglobulin production by peripheral blood mononuclear cells showed a significant increase in IgA1 synthesis, expressed as a fraction of total IgA synthesis in unstimulated cultures (P less than 0.05) and in PWM stimulated cultures (P less than 0.01). Polymeric IgA and polymeric IgA1 production were not higher in patients than in controls. IgM production in unstimulated cultures was significantly (P less than 0.05) higher in patients than in controls. Together with the observed deposition of exclusively IgA1 in the mesangium, our results indicate that patients with IgA nephropathy preferentially produce antibodies of the IgA1 subclass.

Adolescent↗
PubMed1988

The bone marrow as production site of the IgA deposited in the kidneys of patients with IgA nephropathy.

Patients with primary IgA nephropathy have increased plasma levels of polymeric IgA1 and deposits of IgA1 in their kidneys. The origin of this material is unknown. The production of IgA and its subclasses was investigated in the bone marrow of 14 patients and 19 controls using two colour immunofluorescence and tissue culture. Patients had an increase in the percentage of plasma cells containing IgA (45.8 +/- 7.2 mean +/- s.d.) compared to controls (40.1 +/- 10.5) (P = 0.08). IgA plasma cells containing subclass IgA1 were significantly (P less than 0.01) increased in patients (89.9 +/- 2.7%) compared to controls (84.1 +/- 6.7%). Correspondingly IgA plasma cells containing subclass IgA2 were significantly decreased (P less than 0.01) in patients (7.4 +/- 3.0%) compared to controls (13.5 +/- 5.9%). Production of IgA in bone marrow culture in patients was increased (1,684 +/- 1,151 ng/culture) compared to controls (1,087 +/- 937), but this difference was not significant (P = 0.2). However, in patients the IgA1 subclass contributed significantly (P less than 0.01) more to the IgA synthesis in culture (ratio of IgA1 over IgA: 0.96 +/- 0.02) than in controls (ratio 0.90 +/- 0.06). These findings suggest that the bone marrow may well be the site of long-term overproduction of the IgA1 found in the circulation and mesangial deposits in IgA nephropathy.

Adolescent↗
PubMed1987

The 5T2 mouse multiple myeloma model: characterization of 5T2 cells within the bone marrow.

The transplantable C57BL/KaLwRij mouse 5T2 multiple myeloma (MM) is a new animal model for studies on MM in man. Histological examination of the 5T2 MM cells revealed their morphological heterogeneity. In this study we investigated whether this heterogeneity reflects subpopulations of 5T2 MM cells with different biological properties. 5T2 MM bone marrow cells were separated according to their sedimentation velocity (s.v.). When intravenously injected into syngeneic recipient mice, cells with s.v. of 8 mm h-1 led to the development of detectable 5T2 MM after 6 weeks; in contrast, 18 weeks elapsed before the same result was achieved with cells of s.v. lower than 5 mm h-1. Flow cytometric analysis revealed that 5T2 MM cells had an aneuploid DNA content and that most cycling 5T2 MM cells were large, their s.v. rate exceeding 9 mm h-1. It was further demonstrated that about half of all aneuploid cells carried on their membrane the 5T2 MM idiotype. The majority of the idiotype-positive cells had s.v. rate exceeding 6.5 mm h-1 (16%-39%) or lower than 3 mm h-1 (16%-19%). The 5T2 MM was shown to contain subpopulations of cells of different size, proliferation capacity and expression of their membrane 5T2 idiotype; this, most likely reflects cells in different stages of differentiation. The mouse 5T2 MM corresponds also in this respect with MM in man.

Animals↗
PubMed1987

The influence of H-2 genetic factors on the development of benign monoclonal gammopathy in ageing H-2 congenic C57BL and BALB mice.

The role of H-2 genetic factors in the development of benign monoclonal gammopathy (BMG) was investigated in six H-2 congenic C57BL and BALB strains (C57BL/10.ScSn and BALB.B: H-2b; B10.D2 and BALB/c: H-2d; B10.BR and BALB.K: H-2k) during ageing. The frequencies of homogeneous immunoglobulins (H-Ig), both single and multiple, in the three C57BL strains were higher than those in the corresponding three BALB strains. No relationship was found with a particular H-2 haplotype. The most frequent H-Ig isotype within the C57BL strains was IgG2a, within BALB.B and BALB.K mice IgG3 and in BALB/c mice IgG1. Categorization of the monoclonal gammopathies (MG) on the basis of their origin showed a single transient monoclonal B-cell proliferation in 2-5% and 3-9% of the C57BL and BALB mice positive for H-Ig, respectively. Multiple myeloma or B-cell lymphoma were found to be responsible for about 1% of the paraproteinaemias in all strains. Persistent, non-progressive MG, most likely BMG, was detected in 70-81% and 39-46% of the C57BL and BALB mice positive for H-Ig, respectively. The remaining 14-24% and 50-58% of the, respectively, C57BL and BALB mice positive for H-Ig could not be evaluated in time. The H-2 haplotypes under investigation were not associated with the onset, occurrence, multiplicity, persistence or isotype of the MG developing in these H-2 congenic C57BL and BALB strains during ageing.

Aging↗
PubMed1986

Different subclass distribution of IgA-producing cells in human lymphoid organs and various secretory tissues.

A highly reproducible paired immunofluorescence staining method was used to map the relative distribution of IgA1- and IgA2-producing cells in peripheral lymphoid organs and various secretory tissues. Spleen, peripheral lymph nodes, and tonsils all contained a marked predominance (91 to 95%) of IgA1 immunocytes. However, striking variations were demonstrated among the secretory tissues with regard to the median proportion of IgA1-producing cells: nasal mucosa, 96%; lacrimal glands, 81%; major salivary glands, 66%; mammary glands, 63%; gastric and proximal small intestinal mucosa, 84 to 77%; ileum, 55%; and large bowel, 41%. Thus, IgA2 production is relatively enhanced mainly in the distal gut and in mammary and salivary glands, in that order.

Animals↗
PubMed1986

Assay of human IgA subclass antibodies in serum and secretions by means of monoclonal antibodies.

Solid-phase radioimmunoassays have been developed for the detection and quantification of human serum and secretory IgA antibodies to a variety of food, bacterial and viral antigens. Monoclonal antibodies specific for IgA1 and IgA2 and capable of binding to serum and secretory IgA were used. The assays were calibrated by reference to standard serum or purified myeloma proteins bound to solid-phase anti-immunoglobulin reagents, and sigmoid calibration curves were constructed by means of computer programs using 4-parameter logistic or weighted logit-log principles. Polymeric and monomeric forms of IgA antibodies were assayed in fractions separated by high performance size exclusion chromatography. These techniques have demonstrated the expected predominance of IgA1 antibodies in serum, and these included polymeric forms. Saliva contained both IgA1 and IgA2 antibodies, and increased proportions of IgA2 antibodies to lipopolysaccharides and lipoteichoic acid were observed.

Antibodies, Anti-Idiotypic↗