Frantisek Skvaril

Changes of House Dust Mite-Specific IgE, IgG and IgG Subclass Antibodies during Immunotherapy in Patients with Perennial Rhinitis

House dust mite-specific IgE, IgG and IgG subclass antibody responses were evaluated during immunotherapy in perennial allergic rhinitis patients. It was found that IgG4 antibodies steadily increased during treatment, while IgG and IgG1 antibodies reached a plateau 6 months after the initiation of immunotherapy. IgE antibodies also increased during treatment. It was also found that the good clinical outcome was associated with the rate of increase of IgG4 antibodies, but not with IgG, IgG1 or IgE antibodies.

Flow-cytometric analysis of human basophil degranulation. II. Degranulation induced by anti-IgE, anti-IgG4 and the calcium ionophore A23187.

Quantification of human basophil degranulation induced by anti‐IgE, anti‐IgG4, and by ionophore was performed using a flow‐cytometric system. It was shown that these antibodies and ionophore can degranulate basophils in a dose‐dependent manner, and that there is a wide variation in the response of basophils obtained from different individuals to these stimuli. A significant correlation was observed between the degree of degranulation induced by anti‐IgE and anti‐IgG4, while this was not the case for anti‐IgE and ionophore. It was also shown that IgG4 myeloma protein can passively sensitize basophils. In general, degranulating efficacy was in the order of ionophore > anti‐IgE >anti‐IgG4, both in allergic and non‐allergic individuals.

IgG4 Antibodies in Patients with House-Dust-Mite-Sensitive Bronchial Asthma: Relationship with Antigen-Specific Immunotherapy

Sera from 40 patients with house-dust-mite (Dermatophagoides farinae)-sensitive bronchial asthma were evaluated by solid-phase radioimmunoassay for their mite-specific IgG4 antibody levels. Asthmatic patients undergoing specific immunotherapy possessed a significantly higher mean value of IgG4 antibodies than normal controls and asthmatics without immunotherapy (p less than 0.01 and p less than 0.05, respectively). Moreover, evaluation of 11 patients before and after immunotherapy showed that IgG4 antibodies tend to increase during immunotherapy. The clinical significance of the IgG4 subclass as blocking antibodies in immediate allergic reactions is also briefly discussed.

IgG Subclasses in Human γ‐Globulin Preparations for Intravenous Use and Their Reactivity with Staphylococcus Protein A

Abstract. In two of four non‐enzymatically treated γ‐globulin preparations C Immunoglobulin Schura, Immunoglobulin SRK), the distribution of IgG subclasses was found to be close to that of normal human serum. In two other preparations (sulphonated and β‐propio‐lactone‐treated) IgG3 was not detectable by means of appropriate antiserum. The IgG residual portion of plasmin‐treated γ‐globulin was enriched in IgG2, while IgG3 was absent. In affinity chromatography on protein A Sepharose, IgG3 in the unbound and IgG1, lgG2 and IgG4 in the bound fractions were found in Immunoglobulins Schura and SRK. In the sulphonated preparation no IgG was found in the unbound fraction, while IgGl, IgG2 and IgG4 were eluted from the bound fraction. In β‐propioIactone‐treated γ‐globulin IgGl, IgG2 and IgG4 were present in both fractions. The testing of reactivity of IgG subclasses with Staphylococcus protein A can supply important information about the state of the Fc part in immunoglobulin preparations.

The IgG Subclass Distribution in 659 Myeloma Sera

Abstract. The IgG subclass of 659 IgG myeloma proteins was determined with subclass‐specific antisera in agar precipitation technique. The following distribution was found: IgG1, 80%; IgG2, 10%; IgG3, 6.4%; IgG4, 3.6%. In addition, the light chain distribution among myeloma proteins of the subclasses was studied. The K/L ratio of the IgG1 proteins was 1.7; IgG2, 2.05; IgG3, 2.2; and IgG4, 3.0. These ratios did not differ significantly. In 9 sera with IgG double M‐components, the combination IgG1‐IgG4 was found to be predominant.

Differences among available immunoglobulin preparations for intravenous use.

Today almost all IgG preparations for intravenous use (IVIG) fulfill the basic requirements for a preparation given intravenously (sterility, pyrogenicity, antibody content but also anticomplementary activity, etc.). However, there are still marked differences among such preparations caused by the method of preparation: (1) Enzymatically treated IVIGs (by pepsin and plasmin) have a shorter biologic half-time and a disturbed IgG subclass composition; (2) in chemically treated IVIGs (beta-propiolactone, reduced or sulfonated IgGs) the IgG3 subclass is lacking and some of the Fc-related functions are altered; and (3) the IVIGs purified by anion exchangers are poor in the IgG4 subclass. The three main preparations sold in the United States (Gamimune N®, Gammagard® and Sandoglobulin®) belong to the nonmodified preparations and, with the exception of the IgG subclass representation, show similar Fab- and Fc-related properties (antibody content, interaction with Fc receptors on monocytes, phagocytosis-promoting activity, etc.) In none of these preparations, an elevated level of undesired contaminants (prekallikrein activator, irregular anti-erythrocyte antibodies) are found.

Distribution of IgG Subclasses in Commercial and Some Experimental γ-Globulin Preparations

Abstract. The IgG subclass distribution was determined in six commercial and in four experimental human γ‐globulin preparations. The concentrations of IgG subclasses were measured in a modified radioimmunoassay using subclass‐specific antisera. In commercial γ‐globulins, the distribution of the subclasses corresponded roughly lo 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.

Serum Concentrations of IgG Subclasses

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.

Immunoglobulin G Subclass Distribution in Three Human Intravenous Immunoglobulin Preparations

Abstract. In immunodeficiency patients the lack of immunoglobulins (Ig) can be total or partial with a specific IgG subclass imbalance masked by normal values for total IgG. In the latter case therapy with intravenous IgG preparations (IVIG) is generally beneficial, provided the IVIG preparations used originate from large pools of normal blood donors and exhibit a normal IgG subclass distribution. We have analyzed the subclass distribution of three IVIG products: Sandoglobulin® (SAGL), Gamimune®N (GI), Gammagard® (GG), 6–10 lots each, in four different laboratories. The competitive enzyme immunoassays and radial immunodiffusion methods used different monoclonal and polyclonal antibodies specific for IgG1, IgG2, IgG3, and IgG4, respectively. Despite minor interlaboratory differences, the results show that the slightly lower IgG1 content of SAGL versus GI and GG was quantitatively compensated by a higher proportion of IgG2, that no differences existed in IgG3 levels, but that one preparation (SAGL) contained 2–3% of IgG4 compared to 0.5–1.5% in GI and below 0.5% in GG. This difference was significant, the two latter preparations being at or below the lower limit of what are considered to be normal values found in human adults. Such differences may have important clinical consequences.

IgG Subclass Composition and Immunochemical Characteristics of Plasmin-Treated Human γ-Globulin

Abstract. 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.