Physical Binding of Insulin by Gamma Globulins of Insulin-Resistant Subjects12

Burrows, Belton A.; Peters, Theodore; Lowell, Francis C.

doi:10.1172/jci103435

Cited by 74 publications

(18 citation statements)

References 14 publications

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“…Radloimmunoassay for Anti-Glucagon Antibody.--Glucagon was radiolabeled with 125I as described for the iodination of insulin (13). All glassware exposed to the isotope was siliconized.…”

Section: Methodsmentioning

confidence: 99%

The Functional Dissection of an Antigen Molecule: Specificity of Humoral and Cellular Immune Responses to Glucagon

Senyk

Williams

Nitecki

et al. 1971

The Journal of Experimental Medicine

118

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Bovine glucagon, a polypeptide of 29 amino acids, was immunogenic in guinea pigs. The immunologic determinants of glucagon were investigated using isolated tryptic peptides of the hormone. Antibodies from virtually all of more than two dozen animals had specificity primarily for the amino-terminal heptadecapeptide (NM) and showed little or no binding with the carboxy-terminal undeca- and dodecapeptides (C). The smallest synthetic peptide of a series initiated at residue 16 which measurably bound antibody comprised residues 5–16 of glucagon. In cellular immune assays, both NM and C elicited delayed cutaneous reactions and inhibited the migration of peritoneal cells from immune animals. However, only intact glucagon and its C fragment stimulated lymphoid cells to synthesize DNA. While glucagon was somewhat more active than C, the addition of NM to C did not enhance its transforming activity. The smallest synthetic carboxy-terminal peptide with discernible transforming activity comprised residues 19–29 of glucagon. In both native and synthetic C peptide preparations, the undecapeptide was generally more active than the dodecapeptide, although cells from different animals gave different response patterns. The difference between the two is the presence of arginine at the amino-terminus of the peptide chain. Thus, the recognition specificity of populations of antigen-reactive cells from different animals displays a variation which is at least superficially analogous to that of populations of antibody molecules. In limited experiments using NM and C peptides as immunogens, neither gave rise to delayed hypersensitivity or to glucagon-binding circulating antibody, following a regimen which invariably provoked these responses when glucagon itself served as the immunogen. These results indicate that glucagon was cleaved by trypsin along functional lines into two parts, one of which housed the major antigenic determinant and the other of which carried the major immunogenic determinant, and they are highly compatible with a two-cell mechanism of immune induction. An apparent dissociation between the capacity to provoke delayed hypersensitivity reactions and to transform antigen-reactive cells in culture was observed.

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“…Radloimmunoassay for Anti-Glucagon Antibody.--Glucagon was radiolabeled with 125I as described for the iodination of insulin (13). All glassware exposed to the isotope was siliconized.…”

Section: Methodsmentioning

confidence: 99%

The Functional Dissection of an Antigen Molecule: Specificity of Humoral and Cellular Immune Responses to Glucagon

Senyk

Williams

Nitecki

et al. 1971

The Journal of Experimental Medicine

118

View full text Add to dashboard Cite

show abstract

“…In contrast, when serum extracts were incubated without antibody, 40 per cent of the total insulin-I131 was bound and precipitated by extraneous proteins contained in the extract. Figure 3 shows that the addition of 15 per cent urea to the incubation mixtures effectively eliminated almost all of the nonspecific binding in typical serum extracts. Additional salt was required to achieve optimal preferential precipitation.…”

Section: Methodsmentioning

confidence: 99%

“…Thus our inability to detect circulating insulin in human sera could be ascribed to its failure to cross react with these antibodies. Although Burrows and associates (15) The circulating form of insulin may be different from that extracted from the pancreas. This hypothesis has been suggested by the observation that insulin and the "insulin-like" activity in serum are found in different fractions after chromatographic separation on a Dowex-50 column (31).…”

Section: Methodsmentioning

confidence: 99%