A B S T R A C T Lymphocytes that bind in vitro to

Human monocytes contain two distinct receptor sites, one specific for the third component of complement (C'3), the other for immunoglobulin G(gammaG). The two receptors may function either independently or cooperatively in the induction of phagocytosis. Ingestion of erythrocytes coated with immunoglobulin M antibody requires a relatively large number of bound C'3 molecules per cell. Ingestion of erythrocytes sensitized with gammaG antibody is independent of complement; however, the reaction is inhibited by concentrations of gammaG far below those in normal serum. Inhibition by gammaG-globulin is overcome by a relatively small number of bound C'3 molecules per cell. The two monocyte receptors exert a cooperative effect on ingestion by monocytes of erythrocytes coated with gammaG antibody in the presence of inhibitory amounts of free gammaG.

A B S T R A C T Sheep red blood cells can surround, in vitro, some human peripheral blood lymphocytes in a formation called a rosette. The number of rosetteforming cells (RFC) in 50 normal persons had a wide range (4-40%).The organs of 13 human fetuses (11-19 wk conceptional age) were examined for the presence of RFC. The thymus possessed the highest percentage of RFC, the maximum being 65% of total thymocytes in two 15-16 wk fetal specimens. Blood RFC were always present and their number slightly increased in the oldest fetuses. The bone-marrow showed 0-8% in the six fetuses studied. RFC were found in the spleen around the 13th wk and in the liver around the 17th wk of gestation. These observations lead to the hypothesis that human blood RFC may be chiefly thymic derived. Studies of patients with immunological disorders support this hypothesis: one patient with Nezelof syndrome had no blood RFC and four patients with Wiskott-Aldrich syndrome had a low number of blood RFC (1 and 1.5%). Patients with acquired hypogammaglobulinemia showed a normal percentage of RFC. With the fetal thymocytes, the percentage of inhibition with anti-i, serum increased with the fetal age to become complete in the oldest fetuses studied. Incubation of the oldest fetal thymocytes or the blood lymphocytes with anti-e serum or anti-ja serulmi completely inhibited the rosette formation. These results suggest that u-chain determinants are presenit on human fetal thymocytes and blood RFC. The significance of the presence of y-chain determinants on these cells is uniclear.Presented in part at the 84th annual meetiing of the Association

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Previous observations (1, 2) have demonstrated that human ~t-globulin can readily be divided into 7 S and 19 S ultracentrifugal components which differ in chemical (2, 3) and immunological (4,5) properties. Evidence has accumulated that a number of antibodies are associated with the 19 S fraction in normal and pathological animal (6) and human (6, 4) sera. As part of a broad study of these antibodies the present report is concerned primarily with the cold agglutinins found in patients with the syndrome of cold hemagglutination, chronic hemolytic anemia, and paroxysmal cold hemoglobinuria. The possibility that these cold agglutinins are high molecular weight proteins was raised by Gordon (7), who studied a purified preparation of cold agglutinins obtained from the serum of a patient with the cold hemagglutiuation syndrome by adsorption upon, and elution from, washed red cell stromata. The eluted protein showed a sedimentation coefficient of 18 S. The present study deals with the results obtained in an analysis of the sera of 12 patients with acquired hemolytic anemia, (8 with high titer cold agglutinins and 4 with warm incomplete antibodies). Cold agglutinins in all instances were found to be high molecular weight proteins of the 19 S class, in contrast to the warm variety of hemolytic anemia antibodies which had sedimentation coefficients of approximately 7 S. Methods and MaterialsSerologic Metkods.--Titrations of serum and serum fractions were performed at 4 and 37°C. against 2 per cent suspensions of washed, pooled ORb0 + erythrocytes. Parallel titrations were performed using saline suspensions of trypsin-treated and of untreated erythrocytes. Titrations employing the indirect antiglobulin (Coombs) method were performed at 37°C. only. Separate pipettes were used for each dilution to prevent carry-over.Appropriate serologic tests, using a panel of red cells of varying antigenic composition, 1 were performed with each serum to exclude the possibility of specific isoagglutinins toward a given blood group antigen.All titrafions utilizing isolated serum fractions obtained by zone electrophoresis or zone ultracentrifugation of a given serum were performed in parallel.Containing the antigens Rh0, rh', rh",

Recent studies have demonstrated that the factors responsible for the various serological reactions currently employed for the diagnosis of rheumatoid arthritis represent macroglobulins which, in the isolated state, have a corrected sedimentation coefficient of approximately 19S (1-5). In serum and plasma, these proteins exist as complexes with low molecular weight y-globtulins and show a higher sedimentation rate, approximately 22S (6, 7). It has become clear that the rheumatoid factors have a specific affinity for ordinary y-globulin showing a behavior, particularly in certain of the serological tests, like that of anti-y-globulin antibodies. The possibility has been raised that the rheumatoid factor complex in serum represents an antigen-antibody complex.During the course of investigation of the rheumatoid factors and their complexes through ultracentrifugal analyses of sera showing high titer reactions in the latex fixation test and y-globulin precipitin test, another group of y-globulin complexes was encountered. These had sedimentation rates between 9 and 17S and were dissociated in urea and acid buffers in a manner similar to the previously observed dissociation of the rheumatoid factor complexes. Again the question arises as to whether these are antigen-antibody comlplexes or simple aggregates of y-globulin.Gamma globulin components in the 9 to 12S range have been observed in many preparations of normal Fr II y-globulin. The (15,16), although the sedimentation rate of the main abnormal protein was lower than the 18 to 20S range of the proteins described by Waldenstr6m. Macroglobulins of the latter class are a homogeneous group and are known to be stable proteins which do not dissociate in urea and acid and alkaline buffers (17). They have specific immunological properties and dissociate in the presence of agents breaking disulfide bonds (18).In the present study, sera from 11 different patients, 7 with classical rheumatoid arthritis, were found to contain multiple y-globulin complexes. These were readily detected in whole serum and plasma by direct ultracentrifugal analysis. They did not possess rheumatoid factor activity but were associated in the same sera with large amounts of rheumatoid factor. Investigation of the association and dissociation reactions of these complexes was carried out and certain of their properties de-fined. Evidence for and against the hypothesis that they represent antigen-antibody complexes of the y-globlulin-anti-y-glol)bulin type was sought. MATERIAL AND MIIETHODSSix of the 11 patients whose sera were specifically analyzed in this study were observed in the clinic and outpatient department of the Rockefeller Hospital. Three of the remainder represented patients in various New York 1-17