γG Antibodies Research Articles

6. Antibody Activity of Heavy and Light Chains Isolated from Purified Rabbit's γG Antibody(Discussion III. Immunochemistry)

6. Antibody Activity of Heavy and Light Chains Isolated from Purified Rabbit's γG Antibody(Discussion III. Immunochemistry)

Arthus Type Inflammation with Rabbit γM Antibody

Summary Rabbit γM antibody against human type A substance gave precipitin reactions in vitro and induced reversed Arthus type of inflammation in guinea pigs which had received A substance. Preformed complexes composed of A substance and γM antibody also induced the allergic inflammation in normal guinea pig skin. On a weight basis, the minimum dose of the γM antibody for the induction of hemorrhage in reversed Arthus reactions was two to four times as much as the dose of the γG antibody. In the reactions by the preformed complexes, a similar dose of γM and γG antibody in the form of complexes with A substance induced comparable skin reactions.

Studies of incomplete antibodies. II. Interactions with rheumatoid factors and complement.

AbstractNonagglutinating human (anti‐Rh) and rabbit (anti‐G and anti‐g) iso‐antibodies and agglutinating rabbit and hamster γG antibodies against sheep erythrocytes were tested for rheumatoid factor reactivity and for complement‐fixation using papain‐treated and nontreated cells. Although the papain treatment increased the agglutination of the erythrocytes by the antibodies, no change was observed in the complement‐fixing properties. The minimum amount of rabbit γG antibody on the cell surface required for the RF reactivity was the same with papain‐treated and non‐treated cells and of the same magnitude in three serological systems (rabbit incomplete anti‐G and anti‐g and rabbit antisheep cell). This amount of sensitizing antibody was 1/8–1/16 of the amount required for complement‐fixation and for agglutination by a type of RF reactivity that could not be inhibited by native rabbit γG globulin.

The Immunoglobulin Sequence

Summary The local administration of bovine γ-globulin (BγG) to rabbits evoked a characteristic sequence of immunoglobulin synthesis: γM antibodies followed by γG antibodies. This progression of the immune response was disrupted by 6-mercaptopurine (6-MP), and rabbits so treated produced low titers of γG antibodies but normal amounts of γM antibodies. The period of γM synthesis was abnormally prolonged in 6-MP-treated rabbits. Passively infused, specific, reactive γG anti-BγG antibodies arrested the formation of γM anti-BγG antibodies in normal and 6-MP-treated rabbits. A second dose of antigen given to 6-MP-treated rabbits resulted in the rapid appearance of γG antibodies and the cessation of γM antibody synthesis. Splenectomized rabbits given a local injection of BγG had enhanced levels of γG antibodies. Splenectomy abolished the disruptive effects of 6-MP on the immunoglobulin sequence. The results of these experiments indicate: a) the process of γG antibody synthesis is more susceptible to the anti-metabolic action of 6-MP than that of γM formation; b) γG antibody exerts a negative feedback effect on the formation of γM antibody; c) antigen may play a direct and intimate role in the actual synthesis of γG antibodies; and d) under certain conditions, the spleen may inhibit the production of γG antibodies.

Equine antihapten antibody II. The γG(7 Sγ) components and their specific interaction

The γG(7 Sγ) components of antibody prepared against the haptenic group p-azophenyl-β-lactoside (Lac) were isolated from equine antiserum. The average association constants ( K A) for the specific interaction of this antibody with the hapten, p-( p-dimethyl-aminobenzeneazo)-phenyl-β-lactoside (Lac dye), were determined at 25° and 37.2° by equilibrium dialysis. Thermodynamic parameters have been calculated and shown to be very similar to those previously obtained for rabbit anti-Lac antibody. A physical-chemical and immunochemical characterization of the purified γG equine anti-Lac antibody has demonstrated chromatographic, electrophoretic and antigenic heterogeneity. Three antigenically distinct immunoglobulins have been identified in the purified γG anti-Lac antibody each having antibody activity. The antigenic individuality has been related to the heavy chains when compared by immunodiffusion to one another or to γA ( β 2A) antibody from the same serum. A comparison of the binding by the γG antibody with the binding previously described for the γA antibody shows that the affinity of the latter for the Lac dye is much greater. This difference in the affinity for hapten between different immunoglobulins present in the same serum may partially explain the heterogeneity of hapten binding in purified antibody. Furthermore, variation in the relative amounts of these immunoglobulins with time after immunization could in part account for the temporal changes in the affinity of the antiserum for hapten.

On the associated state of rabbit allotypes, the existence of rabbit antibody molecules against two allotypes, and the dissociation of human γ-globulin antigens into smaller molecules

This chapter discusses the physical, chemical, and biological aspects of γM antibodies in depth. The chapter describes the physical characteristics, chemical composition, and subunit structure of the typical circular γM pentomers and the relationship of these molecules to low molecular weight γM-like proteins. The characteristics of the interaction of γM antibodies with antigens—for example, the nature and number of antigen combining sites—and the interaction of γM antibodies with the complement system are compared to the corresponding properties of γG antibodies. The biosynthesis and metabolism of γM antibodies and their peculiar role in the immune response are also discussed in the chapter. The chapter presents a brief summary related to the hallmarks of immunoglobulin heterogeneity and the criteria that must be used to judge the restricted heterogeneity or molecular uniformity of an antibody preparation. The chapter discusses human antibodies to certain selected antigens that appear to possess less heterogeneity than normal γ-globulin.