Post-Gamma Globulin .2. Radioimmunoassay Determination Of Levels Of Post-Gamma Globulin And Beta-2-Microglobulin

Post-gamma globulin previously isolated and partially sequenced in this laboratory was used for production of polyclonal and monoclonal (hybridoma) antibodies. A radioimmunoassay method was developed for quantitation of post-gamma globulin with either antibody. The titration curves obtained were treated statistically and found practically indistinguishable. The sensitivity of the method adopted for the quantitation of post-gamma globulin in a variety of biological fluids was 0.13 ng/ml and the upper limit of precision was 2.5 ng/ml. The following results were obtained (mean ± 1 SD): normal sera, 0.96 ± 0.20 μg /ml; pregnancy sera, 1.08 ± 0.28 μg /ml; cord blood 2.08 ± 0.33 μg /ml; hospitalized patient's sera, 1.3 ± 0.54 μg /ml; geriatric subjects' sera 2.26 ± 1.10 μg /ml; cerebrospinal fluid, 5.37 ± 3.36 μg /ml; saliva, 1.22 ± 0.67 μg /ml; synovial fluid, 1.27 ± 0.41 μg /ml and urine, 0.11 ± 0.125 μg /ml. To shed light on the catabolism of post-gamma globulin the levels of β 2 -microglobulin were also measured radiometrically. Correlative statistical analysis of all the data have shown that renal handling of post-gamma globulin and β 2 -microglobulin may be very similar but not necessarily identical.