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Biomedical subjects

W D Terry

Publications and source records attributed to W D Terry.

At least 73 records · Page 4Linked to original sources

Implications of heavy chain disease protein sequences for multiple gene theories of immunoglobulin synthesis.

The sequence of the amino-terminal 34 amino acids of gamma-heavy chain disease (gamma-HCD) protein Hi is homologous with the amino-terminal region of immunoglobulin heavy chains. gamma-heavy chain disease is smaller than a normal gamma-chain, but has the carboxy-terminal composition expected for gamma-chains and must, therefore, contain an internal deletion. Comparison of the Hi sequence with that of gamma-heavy chain disease Zu, which also has an internal deletion, indicates that the site of internal deletion is not a constant characteristic of gamma-heavy chain disease proteins. Heavy chains can be assigned to subgroups on the basis of variable region sequences. The variable regions of Hi and one other protein differ significantly from those determined for other heavy chains, and these two proteins are assigned to a new heavy chain variable region subgroup, V(HIV). It has been suggested that single immunoglobulin heavy chains are the products of two separate structural genes and that variable region genetic information is translocated and integrated into common region information. These multiple gene theories make no prediction as to whether DNA or RNA is translocated. gamma-heavy chain disease proteins provide unique information that indicates that if translocation is required for the production of immunoglobulin heavy chains, it is DNA, not RNA, that is translocated.

Amino Acid Sequence↗

Metabolic properties of IgG subclasses in man.

Metabolic properties of the four subclasses of human IgG were investigated by performing 47 turnover studies in individuals with normal IgG serum concentrations, as well as in patients with an increased level of one of the subclasses. Studies in 12 subjects with normal IgG serum concentration showed that the average biologic half-life of G(1), G(2), and G(4) was 21 days, while that of G(3) was only 7.1 days. Fractional catabolic rates of G(1), G(2), and G(4) were 6.9 to 8% of the intravascular pool per day. G(3), however, had a higher fractional catabolic rate, amounting to 16.8% of the intravascular pool per day. Distribution of the subclasses was such that the intravascular compartment contained 51-54% of the total body pools of G(1), G(2), and G(4), but 64% of the total body pool of G(3).The short survival and high fractional catabolic rate of G(3) is an inherent property of these molecules, and is not due to denaturation during isolation and radiolabeling. This was demonstrated by studies of a patient with a serum G(3)-myeloma protein. The survival of her own protein, separately labeled either in vivo with guanidoarginine-(14)C or in vitro with (125)I, was determined in the patient. Survivals of the in vivo and in vitro labeled proteins were identical.G(1) and G(3) serum concentrations and synthetic rates were determined. The mean serum concentration of G(1) was 6.8 mg/ml and that of G(3) was 0.7 mg/ml, while their synthetic rates were 25.4 and 3.4 mg/kg per day respectively. The low serum concentration of IgG(2) thus results from a combination of high catabolic and low synthetic rates. Studies in 10 patients with multiple myeloma showed that an elevated serum concentration of any IgG subclass was associated with shortened biologic half-life and increased fractional catabolic rate of all subclasses. The implications of this concentration-catabolism relationship are discussed. The serum concentration of nonmyeloma IgG was usually low in myeloma patients and the synthesis of nonmyeloma IgG was somewhat decreased, suggesting that low serum concentrations of nonmyeloma IgG result from decreased synthesis, as well as from an increased fractional catabolic rate.

Adult↗

Genetics of immunoglobulin kappa-chains: chemical analysis of normal human light chains of differing Inv types.

The relationship between Inv phenotype and the amino acid residue at position 191 in kappa-type light polypeptide chains derived from the immunoglobulins of ten normal human sera was investigated. In each case, the amino acid present at position 191 correlated with the Inv phenotype of the individual. Kappa chains of seven Inv (-1,3) homozygotes had valine, while those of three Inv (1,3) heterozygotes had some chains with leucine and some with valine at this position. Genes encoding the Inv (1) and Inv (3) variants appear to be expressed equally in the heterozygous state, since approximately equal amounts of each gene product was recovered from heterozygotes. The correlation between Inv phenotype and the amino acid residue present at position 191 is identical to that previously established for kappa-type Bence-Jones proteins and myeloma protein light chains. These observations support the hypothesis that the valine-leucine interchange is encoded by two allelic forms of a single kappa-chain common region gene.

Amino Acid Sequence↗