7S Components Research Articles

Immunologic Differences between the 7S and 19S Components of Normal Human γ-Globulin; Antigenic Specificity of the 7S Component

Summary Double diffusion studies in agar and quantitative precipitin studies have confirmed the close antigenic relationship of the 7S and 19S fraction of γ-globulin. Antigenic differences detectable by agar diffusion studies have demonstrated the presence of antigenic groups specific to the 7S γ-globulin which are not present in the heavier fractions. More rapidly sedimenting peaks present in these preparations and in normal serum do not appear to be simple polymers of 7S γ-globulin. Differences in the major 7S fraction of γ-globulin and the 7S units of the 19S fraction of γ-globulin are discussed.

Studies on the isolation and characterization of the "rheumatoid factor".

Considerable evidence has been accumulated which indicates that a large proportion of the sera from patients with arthritis contains a factor which has the property of agglutinating particulate bodies such as red blood cells or latex particles when they are coated with -y-globulin or antibodies. Some of these reactions have been employed as diagnostic procedures and the factor or group of factors involved has been termed the rheumatoid A number of observations (1, 2) have demonstrated that the factor is a y-globulin with the solubility properties of a euglobulin. More recently, ultracentrifuge experiments (3, 4) have indicated that the factor is a high molecular weight -y-globulin that exists in serum and plasma in the form of a complex. This complex can be visualized directly by means of the analytical ultracentrifuge in whole serum and in -y-globulin and euglobulin fractions and has a corrected sedimentation rate (s rate) of approximately 22S. Previous studies (4, 5) on the dissociation of the 22S complex by means of acid and urea have demonstrated that it is composed of two major constituents, one a 7S component and'the other 19S. The latter was found to be highly active by the serological reactions for factor. The factor thus appeared to belong to the 19S class of y-globulins which is known to include certain antibodies as well as the Waldenstrom type macroglobulins (6, 7).