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IgG subgroups (IgG1, IgG2, IgG3, IgG4) were determined by radioim-munoassay (RIA) in cerebrospinal fluid (CSF) of controls, multiple sclerosis (MS), infectious diseases (ID) and other neurological diseases (OND). The proportion of IgG1 in the total IgG subgroup concentration was significantly higher in the MS group compared to the other groups while the IgG2 proportion was significantly lower; IgG3 and IgG4 did not show any consistent change. The inverse relationship between IgG1 and IgG2 was similar in all diagnostic groups: high concentration of IgG1 was associated with low concentrations of IgG2 and vice versa. Patients with a high relative concentration of IgG1 in their CSF have a seven to eight times higher statistical risk to be suffering from MS than ID or OND. In the MS group only the IgG1 concentration correlated with the total IgG concentration determined by radial immunodiffusion, while in controls, ID and OND each IgG subgroup correlated significantly with the IgG concentration. This demonstrates that in MS a selective increase of IgG1 subgroup is mainly responsible for the increase of total IgG, while all subgroups are involved in OND and ID showing an increased total IgG concentration.

Following the 1st IUIS/WHO Collaborative Study of monoclonal anti-IgG subclass antibodies, a panel of WHO Specificity Reference Reagents (SRR) was established [Jefferis, R., et al. (1985) Immunol. Lett., 10, 223]. At the time, the hope was expressed that further reagents particularly for IgG2, and other allotypic specificities would become available which could be applied in a wide range of assay protocols. The 2nd study reports the evaluation of nineteen anti-subclass and seven anti-allotype monoclonal antibodies. The anti-IgG1 antibody HP6187 was equivalent in performance to the SRR. Others, that were not of the mouse IgG1 isotype, may be useful for particular applications. The anti-IgG2 antibody HP6200 could be a valuable addition to the WHO SRR; it is specific for an epitope in the Fab region but does not have the light chain bias of HP6014. Antibodies of putative allotype specificity exhibited the claimed specificity when used within protocols similar to those employed by the originating laboratory. It appears to be inherent in the nature of the epitopes (allotopes) recognized that it will take several years before reagents applicable to a wide range of techniques will become available.

Sera from 27 birch pollen-allergic patients who had undergone hyposensitization treatment for 22-41 months were studied by immunoblotting before and after therapy, whereby the levels of IgE, IgG and IgG1-4 antibodies directed against the major allergen Bet v I and minor allergens of birch pollen were monitored. The clinical benefit of immunotherapy (IT) was evaluated using a symptom specific questionnaire. In patients with good clinical response (responders, n = 18), as defined by improvement of symptoms, anti-Bet v I IgE antibodies were found to decrease in 10/18 patients (55.5%), whereas in 6/18 (33.3%) no change and in two cases (11.2%) an increase of specific IgE was observed. In the group of patients with unsatisfactory clinical outcome (non-responders, n = 9), 3/9 patients (33.3%) showed a decrease, 3/9 (33.3%) no change and 3/9 (33.3%) an increase in levels of IgE antibodies directed against Bet v I. In the case of minor allergens, 5/18 responders (27.7%) and 8/9 non-responders (88.8%) showed specific IgE before IT. In the responder group, no increase of specific IgE could be observed after IT. In non-responders, however, an increase of IgE directed against minor allergens was seen in 3/9 patients (33.3%). In all patients, regardless of therapeutical success, IT-induced elevated levels of specific IgG, IgG1 and in particular IgG4 directed against Bet v I were found. Regarding minor allergens, a heterogeneous pattern of IgG responses without significant correlation to clinical benefit was observed. Our results indicate that changes in IgG reactivity patterns against Bet v I and minor allergens, as shown by the immunoblot technique, did not correlate with good or bad clinical outcome.

We determined isotypes of natural antibodies to streptococcal group A carbohydrate (A-CHO) in sera from 101 children between 1 and 16 years of age, using a calibrated enzyme-linked immunosorbent assay system. Anti-A-CHO IgM could be detected in all but one sera. Median levels increased with age and were highest between 8 and 12 years. IgG antibodies were present at low concentrations up to the age of 4 years, and consisted predominantly of the IgG1 subclass. Between 4 and 8 years, concentrations of anti-A-CHO IgG markedly increased and median levels continued to increase through age 12-16. Anti-A-CHO IgG1 levels closely followed the pattern of IgG antibody concentrations. The number of IgG2 antibody positive sera was low in young children, as expected. In the 8-12 year age group and later, anti-A-CHO IgG2 was present in more than half of the samples, and in children between 12 and 16, medians of IgG2 and IgG1 antibodies were similar. Sera containing anti-A-CHO IgG3 were rare in children up to 4 years of age, but in the group of 4-8-year-old children, this subclass was detectable in 36% and later in up to 77% of the sera. Thus, the IgG response to A-CHO showed a clear maturation during childhood, involving the subclasses IgG1, IgG2 and IgG3. There were no significant differences in A-CHO levels between boys and girls.

Humoral immune parameters were studied in 13 patients with end-stage renal failure on maintenance hemodialysis. Serum IgA, IgM and IgG concentrations were comparable to control values from 14 healthy

51 monoclonal antibodies (McAb) with putative specificity for human IgA, the IgA subclasses, Am allotypes or secretory component (SC) were evaluated for immunoreactivity and specificity by nine laboratories employing immunodiffusion, agglutination, immunohistological assays, immunoblotting and direct binding and competitive inhibition enzyme immunoassays. McAbs specific for IgA PAN (n = 24), IgA1 (n = 7), IgA2 (n = 3), IgA2m(2) (n = 2), non-IgA2m(2) (n = 4) and SC or secretory IgA (n = 5) were identified that were immunoreactive and specific in the assays employed. The McAbs identified as IgA- or SC-reactive were shown to be non-reactive to human IgG, IgM, IgD, IgE, κ and λ by-direct binding and competitive inhibition immunoassays. Interestingly, no McAbs with restricted specificity for IgA2m(l) were identified. Some McAb displayed higher affinity and/or better performance in one or several of the assay groups. The IgA- and SC-specific McAbs identified in this international collaborative study have potential as immunochemical reference reagents to identify and quantitate monomeric and polymeric IgA in human serum and secretions. Chemicals/CAS: Antibodies, Monoclonal; Binding Sites, Antibody; Epitopes; Immunoglobulin A; Immunoglobulin A, Secretory; Immunoglobulin Allotypes; Secretory Component

Sera von 27 Birkenpollen-allergischen Patienten, die uber einen Zeitraum von 22 bis 41 Monaten hyposensibilisiert worden waren, wurden mit Hilfe der Immunoblottechnik untersucht. Es wurden die Veranderungen der IgE-, IgG- und IgG-Subklassenreaktivitaten gegen das Hauptallergen der Birke, Bet v I, sowie gegen Nebenallergene bestimmt. Der Therapieerfolg wurde mit Hilfe eines symptomenbezogenen Fragebogens evaluiert. In der Gruppe erfolgreich hyposensibilisierter Patienten (sogenannte Responder, n = 18) wurde in zehn von 18 Fallen (55,5%) eine Abnahme der gegen das Hauptallergen gerichteten IgE-Reaktivitat beobachtet. Letztere blieb in weiteren sechs Sera (33,3%) unverandert und nahm in zwei Fallen (11,2%) zu. In der Gruppe nicht erfolgreich behandelter Patienten (sogenannte Non-Responder, n = 9) zeigten drei der untersuchten Sera (33,3%) eine Abnahme, drei (33,3%) keine Veranderung und drei (33,3%) eine Zunahme der IgE-Reaktivitat gegen Bet v I.Funf von 18 Respondern (27,7%) und acht von neun Non-Respondern (88,8%) hatten vor der Therapie IgE-Antikorper gegen Nebenallergene. Wahrend die IgE-Reaktivitat gegen Nebenallergene in der Gruppe der Responder im wesentlichen unverandert blieb, lies sich in drei Sera von Non-Respondern eine therapeutisch bedingte Induktion von IgE-Antikorpern nachweisen. Ein Anstieg von IgG-, IgG1- und IgG4-Antikorpern war nach Beendigung der Therapie in jedem Serum festzustellen. Die durch die Behandlung induzierten Veranderungen der gegen Nebenallergene gerichteten IgG- und IgG-Subklassenreaktivitaten waren heterogen und liesen sich in keiner Weise mit dem Erfolg oder Miserfolg der Hyposensibilisierung korrelieren. Diese Studie zeigt, das der blose Anstieg allergenspezifischer IgG-Antikorper nicht als Parameter fur die klinische Wirksamkeit der Therapie angesehen werden kann.

Development of antibody titres in non-vaccinated children with whooping cough of different duration (all confirmed by positive culture) were investigated by ELISA using lymphocytosis promoting factor (LPF, pertussis toxin), filamentous haemagglutinin (FHA), 69 kDa protein and lipopolysaccharide (LPS) as antigens. The antibody responses occur in three different patterns: Firstly, the LPF antibody response develops very quickly starting with the first day of clinical cough with all three classes, IgG, IgM and IgA appearing simultaneously; LPF antibody appears to be a dominant feature. Secondly, FHA and 69 kDa antibodies appear, starting as IgM with the shift to IgG and IgA later. The third pattern is represented by LPS antibody, the IgA appearing early, but with IgM predominant. Higher titres of IgG reacting with LPS were observed in vaccinated children. Transplacental transfer of antibody was also studied. All antibody titres determined in maternal blood and cord blood were proportional except for anti-LPS antibody which was retarded. Most IgG antibody was IgG1 subclass; surprisingly the 69 kDa antibody consisted of a mixture of approx. 90% IgG1 and 10% IgG4.

In 12 patients with homozygotic ZZ-phenotype alpha 1 antitrypsin deficiency, the serum levels of the IgG subclasses IgG1-4 were studied. In four of these patients, isolated or combined disorders or defects in the distribution of the IgG subclasses were detected; in cases with low IgG2 and absent IgG3, the clinical course of the disease was complicated by bronchiectasis.

A marked imbalance of the two light chain types of immunoglobulins was observed in two young male adults suffering from primary hypogammaglobulinemia and intrinsic factor-deficient pernicious anemia. In one patient, the kappa/lambda light chain ratio of serum immunoglobulins was 0.01; in the other, it was approximately 6 (normal value, 1.8 +/- 0.3). This light chain imbalance was found within each of the three main immunoglobulin classes. The number of mature immunoglobulin-producing cells in the bone marrow and in the mucosa of the gastrointestinal tract was reduced. The relative frequency of kappa- and lambda-producing cells in these tissues corresponded to the kappa/lambda ratio of serum immunoglobulins. However, the number of peripheral lymphocytes with membrane-associated immunoglobulins as well as the percentage distribution of blood lymphocytes with kappa- or lambda-type immunoglobulins on the membrane were within normal limits in both cases. The results suggested a hitherto unknown defect in the maturation of B-cells leading to an abnormal ratio of kappa- and lambda- type immunoglobulin-secreting cells.

5 sera from a series of more than 1,000 serum samples from hospitalized patients tested by immunoelectrophoresis were selected for further examination because of a disproportional increase in the anodic part of IgG. A marked polyclonal increase in IgG4 subclass level was detected in each of these sera. While the patients suffered from a variety of diseases (e.g. Loeffler’s syndrome, leiomyosarcoma, periarteritis nodosa, chronic bronchitis, and mycosis fungoides, respectively), they all had an acquired respiratory disease as the only common clinical denominator.

Concentrations of the 4 IgG subclasses, of IgM, and of IgA were determined in culture supernatants of pokeweed mitogen-stimulated mononuclear cells isolated from human peripheral blood. Time-course studies showed cumulative secretion of IgM, IgA, and the subclasses IgG1, IgG2, and IgG3 but not of IgG4. In supernatants of 7-day cultures of unseparated mononuclear cells, IgG1 was predominant, followed by IgG2 and IgG3. Removal of most monocytes from the mononuclear cells resulted in an overall decrease of immunoglobulin production but had no influence on the relative IgG subclass distribution. In supernatants of T cell-enriched cultures, the synthesized IgG was deficient in IgG1. Likewise, in supernatants of B cell-enriched cultures, IgG2 exceeded IgG1 concentration. Elimination of the T gamma cells suggested some influence of this subset on IgG2 production. Gm allotypes determined in supernatants corresponded to those in serum of the blood donors.

Plasmin-treated human γ-globulin, isolated plasmin residual portion (PRG), Fab and Fc fragments were tested for anticomplementary properties. The plasmin digest had very low anticomplementary activity while some of its components were anticomplementary, the latter probably due to alterations resulting from the isolation procedures employed. The highest activity was found in the isolated Fc fragment, no activity being detected in the isolated Fab fragment. Various mixtures of the isolated components were also tested, the results indicating that the increase in anticomplementary activity of the PRG and of the Fc fragment was markedly lower when the Fab fragment was present.

Three laboratories took part in an investigation about the possibilities of quantitative determination of IgG subclasses. Polyclonal monospecific antisera were used in combination with different kinds of calibrators to assess the IgG subclass levels in three W.H.O. reference preparations. IgG 1 could be determined with satisfactory precision; for the other subclasses the quantification was less precise. The precision was dependent on the antisera for IgG 1, IgG 2 and IgG 4 but mainly on the calibrators for IgG 3. Mass units are to be preferred to relative units. W.H.O. reference preparation 67/97 is proposed as a reference for determination of IgG subclasses in mass units. The target values are 5.0 g/l for IgG 1, 2.6 g/l for IgG 2, 0.4 g/l for IgG 3 and 0.5 g/l for IgG 4. These values add up to a total IgG value close to earlier W.H.O. estimates.

Amyloidosis associated with plasma cell dyscrasia (AAPCD) is a relatively rare clinical entity (4% of our patients with PCD) and its early recognition and distinction from multiple myeloma (MM) may be of great therapeutic and prognostic significance. Laboratory parameters, such as concentrations of normal polyclonal Ig, Bence-Jones proteins and serum monoclonal components (MC) showed in our patients lower MC concentrations than in MM, lambda-L-chains and of gamma-H-chains predominating. Sequential skeletal X-ray studies and bone marrow morphology remain essential diagnostic procedures. Due to the lack of efficient therapeutic agents for AAPCD and the great progress achieved in recent years in the treatment of secondary amyloidosis, the immunochemical analysis of the isolated amyloid fibril as well as of the surrounding 'ground substance' should be pursued in AAPCD. Our data support previous observations, that in AAPCD the amyloid fibril subunit is an L-chain fragment predominantly derived from lambda-L-chains which originates from the same clone as the MC. The localization of an enzymatic cleavage point on the L-chain, the detection of a specific proteolytic enzyme and the identification of additional components in the amyloid substance, may further elucidate the etiopathogenesis of AAPCD.

January 1976 3. Results The CD spectra of eight different IgA M-components are illustrated in fig. 1 A (two IgAl K and two IgAz K proteins) and in fig.1 B (two IgAl L and two IgAz L proteins). Three of the IgA2 proteins were of the genetic variant AZ m (l+, 2-), one (protein San) belonged to the AZ m (l-, 2+) type. All IgA proteins studied show essentially similar spectra in the wavelength region between 190 and 300 nm characterized by a major negative transition around 217 nm, and by the absence of any positive transitions. The wavelength of the negative trough and the corresponding mean residue weight ellipticity for the eight different IgA proteins and the corresponding values for human IgG, IgM, IgD and IgE taken from the literature [ 13- 161 are given in table 1. Apparently protein San, which belongs to the AZ m (1-, 2+) genetic variant displays a much smaller mean residue weight ellipticity value than any other human immunoglobulin of either class or subclass. Moreover, the

The IgG subclass distribution was determined in six commercial and in four experimental human gamma-globulin preparations. The concentrations of IgG subclasses were measured in a modified radiommunoassay using subclass-specific antisera. In commercial gamma-globulins, the distribution of the subclasses corresponded roughly to the distribution in normal human serum. A considerable enrichment of the IgG 4 was found in experimental lots prepared either from the ethanol fraction III or from the rivanol-precipitable IgG.

We determined immunoglobulin G (IgG) subclass concentrations and studied their distributions in the cerebrospinal fluids of patients suffering from multiple sclerosis, other inflammatory neurological diseases, and non-inflammatory diseases of the nervous system in comparison with a control group. In addition, the four subclass concentrations were measured in serum specimens of the multiple sclerosis and control groups. These data were correlated with the extent of local IgG synthesis in the subarachnoid spaces of the patients belonging to the different groups. We found a selective elevation of the IgG1 subclass in the cerebrospinal fluids of multiple sclerosis patients, and there was only a very small overlap of the IgG1 ranges of the multiple sclerosis and control groups. No major differences were detected between the IgG subclass distributions in different courses of multiple sclerosis nor between multiple sclerosis and control sera. The group with non-inflammatory diseases showed a uniform elevation of all four subclasses and a greater overlap with the normal range. This latter feature was combined with an elevated IgG1 concentration in the group with other inflammatory diseases. It is concluded that locally synthesized IgG in the cerebrospinal fluids of multiple sclerosis patients consists mainly of IgG1.

Plasmin-treated gamma-globulin of placental origin was tested in clinical and laboratory studies and found to be suitable for intravenous use both for prophylactic and therapeutic purposes. Plasmin treatment of gamma-globulin (IgG) results in proteolytic cleavage of 60-70% of the molecules into Fab and Fc fragments whereas 30-40% of the molecules are plasmin resistant. The antibody spectrum of plasmin-treated gamma-globulin is similar to that of standard gamma-globulin. Catabolic properties of the plasmin-resistant portion of this preparation and of standard gamma-globulin are identical. Plasmin-treated gamma-globulin has no anticomplementary activity and its intravenous administration is well tolerated even by highly sensitive immunodeficient patients.

Following the 1st IUIS/WHO Collaborative Study of monoclonal anti-IgG subclass antibodies, a panel of WHO Specificity Reference Reagents (SRR) was established [Jefferis, R., et al. (1985) Immunol. Lett., 10, 223]. At the time, the hope was expressed that further reagents particularly for IgG2, and other allotypic specificities would become available which could be applied in a wide range of assay protocols. The 2nd study reports the evaluation of nineteen anti-subclass and seven anti-allotype monoclonal antibodies. The anti-IgG1 antibody HP6187 was equivalent in performance to the SRR. Others, that were not of the mouse IgG1 isotype, may be useful for particular applications. The anti-IgG2 antibody HP6200 could be a valuable addition to the WHO SRR; it is specific for an epitope in the Fab region but does not have the light chain bias of HP6014. Antibodies of putative allotype specificity exhibited the claimed specificity when used within protocols similar to those employed by the originating laboratory. It appears to be inherent in the nature of the epitopes (allotopes) recognized that it will take several years before reagents applicable to a wide range of techniques will become available.

The relative cytoplasmic immunoglobulin content of fixed plasma cells taken from the bone marrow of five patients with myeloma and five patients with benign monoclonal gammopathy was determined with a microscope fluoro-meter. In eight of the ten plasma cell populations studied, the distribution of the fluorescence intensities was close to normal. In three of these eight populations a significant difference in the variances of the heavy and light chain fluorescence intensities was found. Variances of heavy and light chain fluorescence intensities were smaller in patients with an immunoglobulin A-type gammopathy than in those with an immunoglobulin G-type gammopathy. No difference was found if normalized relative frequency distribution patterns of heavy or light chain fluorescence intensities of patients with myeloma were compared with those of patients with benign monoclonal gammopathies.

Twenty-three epileptics with constitutional factors for seizures and low IgA serum concentrations were studied. Imbalance of the IgG subclasses was often observed, the IgG4 being undetectable in 13 (65%) patients. The percentage of circulating lymphocytes positive for surface immunoglobulins was normal except for slightly increased values for IgA in six (28.5%) patients. Of the epileptics, 48% showed subnormal proportions of lymphocytes forming spontaneous rosettes. There was a distinct trend for HLA-A2 antigen in the patients tested.

To determine the importance of genes located in or near the Ig constant regions in regulating the human antibody response, we correlated Ig allotypic markers with total Ig concentrations and natural antibody concentrations to the streptococcal group A carbohydrate (A-CHO) in 193 healthy adult blood donors. The major correlations between Ig allotypes and total Ig and specific antibody concentrations were observed with the Gm(f;n;b) haplotype. When compared with Gm(f;n;b) negative individuals, Gm(f;n;b) positives had significantly higher concentrations of total IgG2 (p less than 0.001) and IgG2 anti A-CHO (p less than 0.05), lower concentrations of total IgG1 (p less than 0.001) and IgG1 anti A-CHO (p less than 0.001), and lower concentrations of total IgM (p less than 0.001) and IgM anti A-CHO (p less than 0.05). We conclude that individuals with the Gm(f;n;b) haplotype respond preferentially with IgG2 rather than IgG1 subclass antibodies. This increased capacity to respond with IgG2 antibodies may be reflected in the magnitude of the total antibody response when the IgG2 subclass comprises a major proportion of the response, as occurs in the adult response to many polysaccharide Ag.

Plasmin-treated human IgG preparations were separated on Sephadex G-100 columns, and proteins of three peaks eluted prior to Fab/Fc fragments were investigated. Determinations of the apparent molecular weight of these peaks revealed that IgG dimers, plasmin-resistant IgG monomers and additional components with a molecular weight of about 115,000 were eluted. IgG subclasses were measured in individual effluent fractions and χ, Λ and IgG/Fc antigenic determinants were demonstrated. IgG2 and IgG4 were found to be relatively resistant, IgG1 and IgG3 susceptible for cleavage by plasmin. In the components with a molecular weight 115,000, two fragments were characterized and shown to be similar to the papain IgG1-Fab/c and IgG1-Fc2 fragments.

The class, subclass and light chain distribution of eight myeloma proteins with anti-streptolysin·activity (ASO) in sera studied by our group and in cases from the literature indicates a predominance of the IgG1 kappa subclass and type of immunoglobulins. Three IgG myeloma proteins (O.I., L.F. and A.S.) were further characterized with respect to idiotypic cross-reaction and variable region subgroup. The anti-idiotypic antibodies (anti-Id) against protein O.I. and against protein L.F. both indicated idiotypic cross-reaction between O.I. and L.F. While in the case of anti-IdL.F. this cross-reaction was in the order of 5% it was much weaker when studied with anti-IdO.I.·The reaction between O.I. and anti-IdO.I. could be inhibited to 95% by the antigen streptolysin O, indicating that the idiotypic determinants are associated with the combining site. N-terminal amino acid sequence analysis showed that all three light chains fall into the VκIII variable region subgroup. The heavy chains of proteins O.I. and L.F. with idiotypic similarities both have blocked N-termini, indicating the presence of the VHI or VHII subgroup while protein A.S. belongs to the VHIII subgroup.

Plasmacytoid cells in the bone marrow of 3 patients with myeloma and plasma cells in the bone marrow of a 6-year-old boy with an infectious disease were assessed cytophotometrically, first after Giemsa-and second after Feulgen staining. The cell and nuclear surface and the nuclear/cytoplasmic ratio were determined from the number of measuring points. The nuclear DNA content of individual cells was registered and the distribution of DNA within the nucleus was assessed by the distributional error. Both the mean nuclear/cytoplasmic ratio and the distributional error of myeloma cells varied from patient to patient but could not be used to differentiate between normal plasma cells and myeloma cells. It was not possible either to differentiate these cell types by multiplying the mean nuclear/cytoplasmic ratio with the mean distributional error of the nuclear DNA. A strong correlation between cell and cytoplasmic surface area was observed both in normal plasma cells and in myeloma cells.

High doses of intravenous immunoglobulin were given to seven pregnant women between the 27th and 36th wk of gestation who were at risk for preterm delivery. Determinations of IgG subclasses and of antibodies against group B streptococcal serotypes, pneumococcal polysaccharides, and tetanus toxoid were done in maternal serum before and after intravenous IgG infusion and after delivery in cord serum. Substantial transplacental passage of the infused material could be observed in five cases where delivery occurred at the 34th wk or later. After the 36th wk of gestation, IgG subclass and antibody concentrations in cord serum were increased up to the levels in the maternal serum.

Patterns of surface and cytoplasmic immunoglobulins were simultaneously studied on human B blast cells induced by pokeweed stimulation of peripheral blood lymphocytes. A double-staining immunofluorescent technique was used. After 4 and 7 days of culture, a gradual loss of surface IgD was observed on blast cells whereas numbers of plasmablasts with cytoplasmic immunoglobulin showed a marked increase. After 7 days, 92% of surface IgA positive blasts had passed terminal differentiation to cytoplasmic IgA-producing plasma-blasts. At the same time, 73% of surface IgM positive blasts were found to contain cytoplasmic IgM, and 30% of surface IgG positive cells had cytoplasmic IgG. Only a small fraction of blast cells with surface IgD was able to mature to IgD producing plasmablasts. In general, the class of surface and cytoplasmic immunoglobulin coincided in single blast cells, with the exception of surface IgD which was present on 10% of the cytoplasmic IgM-containing blasts.

Immunoglobulin G (IgG) antibodies against hepatitis B surface antigen were found to be restricted to subclasses IgG1 and IgG3 in serum samples of 17 individuals. Quantitative determinations showed that in 10 samples the minor serum subclass IgG3 contained more antibodies than the predominant subclass IgG1. Ranges of concentrations were between 0.72 and 16.50 micrograms/ml for IgG3 antibodies and between 0.55 and 6.19 micrograms/ml for antibodies of subclass IgG1.

IgG subclasses in anti-HBs antibodies in sera from 9 vaccinated (H-B-Vax, Merck, Sharp & Dohme) individuals and from 18 individuals with naturally acquired anti-HBs were characterized in enzyme-linked immunosorbent assay with monoclonal subclass-specific antibodies. Also eight hyperimmune immunoglobulin preparations from five producers were investigated. In vaccinated persons, the activity was predominantly present in IgG1 and IgG4 subclass. Various combinations of subclasses in anti-HBs antibodies were found in persons after recovery from hepatitis B and in immunoglobulin preparations. The serum concentration of subclasses does not reflect the subclass profiles of the anti-HBs antibody.

Im Serum von normalen Individuen wurden die Immunglobuline vomx- und λ-Typ quantitativ bestimmt und das x/λ-Verhaltnis auf verschiedenen Altersstufen ermittelt. Es hat sich gezeigt, das die relative Konzentration der λ-Immunglobuline im Serum der Sauglinge signifikant hoher ist als im Erwachsenenserum. Die bekannte asynchrone Ausreifung der Immunglobulin-Klassen und IgG-Subklassen im fruheren Lebensalter wird offensichtlich durch eine ebenfalls ungleiche Ausreifung der Immunglobulin-Typen uberlagert.

The IgG2 and IgG4 levels in 55 serum samples from family members with known Gm (23) genotype were studied. No correlation between IgG2 or IgG4 concentration and age or between these subclasses and sex was observed. Gm (23) shows no marked effect on the concentration of IgG2, but the concentration of IgG4 in serum is in the sequence Gm (23) homozygotes τ; Gm (23) heterozygotes τ; Gm (-23), and the differences are significant. Since the IgG4 allotype 4b appears, on the basis of limited data, to be transmitted with Gm (23), the observed relation between the Gm (23) genotype and IgG4 concentration may be due to an effect of 4b and not to Gm (23). More data are needed.

Indirect hemagglutination studies were performed on 10 incomplete anti-Rh sera from mothers after incompatible pregnancies, on 19 incomplete anti-Rh plasma samples from preimmunized and repeatedly boosted individuals and on 3 anti-Rh plasma pools. Group O Rh-positive red blood cells were agglutinated by antisera to immunoglobulins. Anti-Rh antibodies after incompatible pregnancies were found to belong to the immunoglobulin class IgG and to the subclasses IgG1, IgG3 and IgG4 only. In most anti-Rh samples from preimmunized and repeatedly boosted subjects, IgG and IgA were present. In six anti-Rh samples of this group, the subclass IgG2 could be demonstrated.

The four subclasses of IgG were quantitatively determined in a panel of fetal and maternal sera. It was found that all four subclasses pass from the mother to the fetus.

An improved method for the isolation of normal immunoglobulin E is described. The method is based on the use of an immunoadsorbent formed by the mechanical entrapment of antibodies against a myeloma immunoglobulin E into a lattice of a highly cross-linked macroporous polyacrylamide gel. Normal immunoglobulin E was isolated from an immunoglobulin E-rich serum pool as well as from an individual healthy donor. The isolated immunoglobulin E was contaminated with about 20% of immunoglobulin G. An antiserum against normal immunoglobulin E was prepared by immunizing rabbits with the isolated immunoglobulin E.

The concentrations of the four recognized subclasses of IgG were measured usingspecific antisera and a radioimmunoadsorbent assay in 38 paired maternal and cord blood samples and in the sera of 95 presumably healthy infants from birth to 2 years of age. Placental transfer of all four subclasses was found to be free. The dramatic changes of the total gamma globulin concentration in the neonatal period were confirmed. However, analysis of the subclasses revealed considerable heterogeneity, leading to the conclusion that for each subgroup there is a different age of onset and speed of synthesis: Within one month after birth IgG 3 values rise to considerable levels and after three months to adult levels. IgG 1 synthesis starts before three months of age and concentrations are close to adult values at 8 months, whereas IgG 2 and IgG 4 synthesis still is far from maturity at age 2 years. Possibly the nature of the stimulating antigens is a determining factor of the resulting IgG subclass responses.

The concentrations of the four subclasses of IgG were determined in the sera of 108 young male adults. The relative concentrations are 60.9% for IgG1, 29.6% for IgG2, 5.3% for IgG3 and 4.2% for IgG4. Mean concentrations of IgG2 and IgG4 are higher in sera positive for Gm(23) than in sera lacking this genetic marker. High mean IgG3 concentrations are associated with sera homozygous and heterozygous for Gm(3,5,13,14).

It was shown that anti-bee venom phospholipase A2 antibodies (anti-PLA) of bee keepers belong mainly to the IgG4 class. Furthermore anti-PLA of different individuals are idiotypically related to each other. This was shown by the binding of heterologous antiidiotypic antibodies, produced against anti-PLA IgG from single donors, to anti-PLA F(ab′)2 of different individuals. Therefore, the anti-PLA response provides a human model to study the idiotypic regulation of isotypes in a defined system.

Bone marrow samples of 28 individuals with clinically benign and of 41 patients with malignant monoclonal gammopathy were analyzed for the total number of lymphoplasmocellular elements containing cytoplasmic immunoglobulins and for the monoclonal fraction of these cells. Monoclonal immunoglobulin components were determined in sera. A discriminant analysis was performed on the data: the variables were transformed and in a stepwise procedure used for the construction of a discriminant function which by adividing point allowed a good distinction between the two groups of patients. By use of this discriminant function, 91% of the patients in the sample were correctly classified.

Publisher Summary The molecules of the immunoglobulin class IgG include 70–80% of the humoral antibodies. Their wide antibody spectrum is a corollary of the enormous heterogeneity of the antigen binding sites and is structurally confined to the variable region of the IgG molecules. Four subclasses of IgG are recognized: IgGl, IgG2, IgG3, and IgG4. The molecules of these subclasses differ in the primary structure of the carboxyterminal three-quarters of their heavy polypeptide chains, number and arrangement of the inter-heavy chain disulfide bridges, and the localization of the disulfide bridges linking the heavy to the light polypeptide chains. There is evidence that subclass-related structural traits are located in all three homology regions of the IgG heavy chains. The determination of the serum concentrations of the four IgG subclasses could offer some insight into the regulatory mechanisms that control subclass serum levels and could bring some new information on their biological significance. This chapter discusses the radioimmunoassay of the four IgG subclasses. In addition to its higher sensitivity, the method allows the scanning of large numbers of sera with minimal quantities of antisera.

Serum IgE and IgG4 concentrations were determined in 102 children with atopic dermatitis (AD) of varying severity and activity. Total as well as specific IgE levels, determined by the radioallergosorbent test (RAST), were correlated with disease severity and the coexistence of atopic respiratory diseases. The IgG 4 levels of children with only AD, even in severe cases, were within the normal ranges of healthy children. In contrast, the IgG4 levels of children with both cutaneous and respiratory atopic manifestations were elevated, suggesting that IgG4 are probably associated with respiratory diseases but do not play any role in the pathogenesis of the skin disorder.