Abstract
Discussion and Summary
A series of precipitin reactions in agarose gel are described which resemble, but are unrelated to antigen-antibody reactions commonly studied by similar methods. This appears to be due to the lack of interference in agarose by sulfate groups present in ordinary agar. The reactions appear to be due to complexes formed between highly negatively charged compounds such as dextran sulfate, heparin, and inositol phosphatide and the highly positively charged polymyxin and aminoglycoside antibiotics, lysozyme, protamine, DEAE-dextran, and presumably beta lipoproteins as well. Unfortunately, the formation of a precipitin band between human serum and dextran sulfate and sensitivity limited to antibiotic concentrations several-fold higher than achieved during antimicrobial therapy, prevents direct adaptation of these methods to a rapid procedure for detecting basic antibiotics in serum. The approach could conceivably be adapted to measurement of basic drugs in urine or to ultrafiltrates of serum.
Evidence is presented that the precipitin band formed between human serum and dextran sulfate is due to complexes formed with beta lipoproteins. A simple method for screening for hypo-beta lipoproteinemia is described. It is unlikely that protamine is present in sufficient concentrations in human serum to account for this band. Human serum contains small amounts of lysozyme, but in somewhat lower concentrations than can be measured by the precipitin reactions reported here with dextran sulfate. Osserrnan (5) reported lysozyme levels of about 7 μ/g ml in human serum, while dextran sulfate detects about 64 μ/g/ml. It is possible that dextran sulfate could be useful in detecting lysozyme in urine of patients with monocytic leukemia and other diseases.
A non-antigen–antibody precipitin reaction in agarose has recently been described by Gardner and Rosenberg (7) between a lipoidal tissue extract and an IgM serum component. Several other isolated reports of similar phenomina are cited by these authors.
Get full access to this article
View all access options for this article.