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Biomedical subjects

J D Capra

Publications and source records attributed to J D Capra.

At least 253 records · Page 14Linked to original sources
PubMed1976

Structural studies on protein products of murine chromosome 17: partial amino acid sequence of an H-2Kb molecule.

By use of single internal radiolabels, 17 of the NH2-terminal 27 amino acids of the murine H-2Kb molecule have been assigned. When the amino acid sequence is compared to that of the murine H-2Kk molecule, there is a minimum of six amino acid differences in 19 positions. This high degree of structural diversity confirms, at the level of amino acid sequence, the known polymorphism of the murine H-2 complex. Significant primary str-ctural homology is evident when the murine H-2Kk and H-2Kb sequences are compared to the recently reported partial amino acid sequences of human transplantation antigens. There is modest homology with beta2-mictoglobulin and immunoglobulins, but the available sequence information is insufficient for a satisfactory evaluation of its significance.

Alleles↗
PubMed1976

The partial amino-acid sequence of an H-2K molecule.

Eighteen of the NH2-terminal 27 amino acids of a murine H-2K molecule have been assigned. The approach used was to label murine splenocytes with a single radioactive amino acid, isolate the H-2K molecule by specific immunoprecipitation, electrophorese the dissolved precipitate on sodium dodecyl sulfate polyacrylamide gels, and subject the isolated H-2K peak to amino-acid analysis and automated sequencing.

Amino Acid Sequence↗
PubMed1976

Complete amino acid sequence of the variable domains of two human IgM anti-gamma globulins (Lay/Pom) with shared idiotypic specificities.

On the basis of extensive shared idiotypic specificities, two human IgM anti-gamma-globulins (Lay/Pom) were selected for complete amino acid sequence analysis of their variable domains. Previous studies on the variable regions of the heavy chains of these proteins had shown but eight amino acid differences, only one of which was within a complementarity-determining hypervariable region. The complete amino acid sequence of the variable regions of the light chains of these two proteins is the subject of this report. Protein Lay is a typical VchiI protein with only five 'framework' differences when compared with protein Roy. Protein Pom is best classified as a VchiII, but in the 'framework' there are 16 differences between it and protein Ti. Although there are extensive differences in the first hypervariable region, the second and third light-chain hypervariable regions have an identical sequence. The finding of two identical light-chain and two identical heavy-chain hypervariable regions in these two proteins, which were selected on the basis of their combining specificities and their idiotypic cross-reactions, strongly implicates hypervariable regions in the constitution of the idiotypic determinants and the antibody combining site. Additionally, the finding of identical hypervariable regions in light chains of different V-region subgroups fulfills a prediction of the gene-interaction concept of antibody variability.

Amino Acid Sequence↗
PubMed1976

Structural studies of induced antibodies with defined idiotypic specificities. IV. The heavy chains of anti-streptococcal group A carbohydrate antibodies from Sprague-Dawley rats carrying a cross-reacting idiotype.

The heavy (H) chains of three anti-streptococcal group A carbohydrate antibodies (anti-SACHO) of restricted heterogeneity, elicited in inbred Sprague-Dawley rats, were subjected to 40 cycles of automated Edman degradation. All three antibody H-chain preparations had an identical amino acid sequence and were classified as a variant of the VHIII subgroup of immunoglobulin H chains. A comparison of the H-chain sequence of these antibodies with that of pooled rat gamma chains suggests that a very minor population of H chains (closely related to the VHIII subgroup) has been 'recruited' as a consequence of this immunization. This observation further supports the notion that 'framework' and 'specificity' or 'hypervariable regions' are closely linked.

Amino Acid Sequence↗
PubMed1976

Structural studies on induced antibodies with defined idiotypic specificities. III. N-terminal amino acid sequence of the heavy and light chains of mouse anti-streptococcal antibodies--A5A, S8, and S117.

The murine VH genetic map consists of two different subloci of VH genes. Seven idiotypes have been allocated to these two different subloci, one of which contains genes coding for the A5A idiotype, while the second contains the genes encoding for six other idiotypic markers. Previous studies from this laboratory have shown that anti-Ars antibodies are best classified in the murine VHII subgroup. Studies from other laboratories indicate that the J558 idiotype could be classified in a similar fashion. The sequence of the T15 myeloma protein VH region is most characteristic of the murine VHIII subgroup. These studies were undertaken in order to study the VH subgroup of two additional murine VH markers. Since one of these markers has been allocated to a separate sublocus, comparisons can be made for the first time between the "framework" residues (VH subgroup) and the murine genetic map. The data indicate that within a single presently defined sublocus proteins exist which contain remarkably different "framework" residues.

Amino Acid Sequence↗
PubMed1975

Studies on the murine Ss protein. I. Purification, molecular weight, and subunit structure.

The murine Ss protein has been isolated and purified. Using specific antisera, the radiolabeled protein has a mol wt of 120,000 in sodium dodecyl sulfate polyacrylamide gels. It is composed of two basic subunits of 23,000 and 14,000 daltons. The smaller molecular weight subunit contains a single disulfide bridge, is devoid of carbohydrate, and may represent the murine equivalent of beta2-microglobulin.

Amino Acid Sequence↗
PubMed1975

The amino acid sequence of ragweed pollen allergen Ra5.

The complete amino acid sequence of Ra5, a ragweed pollen allergen, has been determined. Allergen Ra5 is a low molecular weight protein of 45 residues derived from Ambrosia elatior, the short ragweed. It contains no detectable carbohydrate or lipid and has four disulfide bridges. The total structure was determined on 1.4 mumol of material and indicates that structural analysis is increasingly possible on relatively small amounts of highly purified material when a combination of automated and manual sequencing techniques and highly sensitive detection systems is employed. This represents the first complete amino acid sequence of a ragweed allergen and it should provide a basis for many structure-function correlative experiments in the field of immediate hypersensitivity.

Alkylation↗
PubMed1975

Bence Jones proteins and light chains of immunoglobulins. XI. A transient Bence Jones-related protein associated with corticosteroid therapy.

Urine specimens from patients with multiple myeloma and Bence Jones proteinuria frequently contain low molecular weight proteins which correspond either to the amino-terminal, variant half (VL) or to the carboxyl-terminal, constant half (CL) of the Bence Jones protein. Analyses of urine specimens from such patients who had received high doses of corticosteroids as part of their treatment regimen revealed that concomitantly with a decrease in Bence Jones protein excretion was the appearance of a low molecular weight protein related to the Bence Jones protein but not identical to the VL or to the CL. Analyses of daily urine specimens obtained from one such patient over an extended time period revealed that a reproducible chain of events occurred during a treatment regimen which included oral administration of 75 mg of prednisone daily for 7 consecutive days. The amount of Bence Jones protein excreted decreased progressively, and by the 5th day was usually less than 10% of the pretreatment value. The urine specimen obtained on the 6th day of treatment was virtually devoid of Bence Jones protein but contained a newly appearing protein whose electrophoretic mobility was distinct from that of the Bence Jones protein or its VL or CL. Cessation of corticosteroid therapy resulted in a prompt disappearance of the new protein and in a progressive increase in the amount of Bence Jones protein excreted. The new protein was isolated from the urine of this patient and was purified for comparative studies with Bence Jones protein and with the VL and CL prepared by specific enzymatic cleavage of the Bence Jones protein. These studies revealed that the new protein was most related antigenically to the CL, but could be distinguished immunochemically from the CL. This new protein, a component found in vivo related to the constant half of the light polypeptide chain, was designated CL, and was structurally 25 amino acid residues longer than the CL, that is, the amino-terminus of the enzymatically prepared CL was at position 117 whereas that of the transitory new Bence Jones-related protein was at position 92 of the light polypeptide chain. Biosynthetic studies were performed with plasma cells derived from the bone marrow of this patient at a time when both the CL and the Bence Jones protein were being excreted; both proteins were identified in extracellular culture fluid by immunochemical techniques. Whether the CL is of synthetic or catabolic origin is presently not known; however, the detection of the CL and the absence of any detectable protein related to the VL in the extracellular culture fluid might imply a synthetic origin of the CL and suggest a corticosteroid-induced alteration in light chain synthesis.

Amino Acid Sequence↗
PubMed1975

Idiopathic polyneuropathy associated with cytotoxic anti-neuroblastoma serum. IgG and IgM immunoglobulin studies.

Serums from six patients with progressive idiopathic acute or chronic polyneuropathy possessed a cytolytic activity against transformed mouse cholinergic or noncholinergic neuroblasts but not against transformed rat astrocytes. This activity was not qualitatively nor quantitatively present in serums from normal controls or from patients with a variety of other motor system disorders and other neurologic disorders. Fluorescein conjugated goat antihuman IgG and IgM monospecific immunoglubulins were used to characterize further the cytotoxic activity from patient serums and these studies suggested the presence of immunoglobulin G (IgG) and immunoglobulin M (IgM) directed against a cell surface neuroblastoma antigen. Cold reactive immunoglobulins of the IgG and IgM type were present in the serums of all six patients. A bioassay is described that may be helpful in evaluating other patients with progressive idiopathic polyneuropathies.

Adolescent↗
PubMed1975

Structural studies on induced antibodies with defined idiotypic specificities. II. The light chains of anti-p-azophenylarsonate antibodies from A/J mice bearing a cross-reactive idiotype.

N-terminal amino acid sequence analyses have been performed on three preparations of light chains of A/J mice. Light chains derived from the IgG of unimmunized animals were compared to light chains of anti-p-azo-phenylarsonate (anti-Ar) antibodies possessing a cross-reacting idiotype (CRI); the latter were derived from the ascites fluid of a single A/J mouse, or from the pooled ascites fluids of 18 A/J mice. The heavy chains of these same two antibody preparations had previously been shown to comprise a single, homogeneous sequence to position 40. With few exceptions, the first 26 positions of light chains derived from unimmunized animals were extremely heterogeneous; the heterogeneity is comparable to that observed in a composite of sequence data on light chains of BALB/c myeloma proteins. Although the light chains obtained from anti-Ar antibodies possessing the CRI (whether from the pool of 18 A/J mice or from a single mouse) were more restricted in their sequence, at several positions as many as four alternative amino acids were detected. These studies indicate that an antibody population with defined idiotypic specificity, and very possibly identical heavy chain sequences, may contain at least four distinct light chains. The feasibility of structural studies on antibodies induced in individual mice is further demonstrated.

Amino Acid Sequence↗
PubMed1975

Structural studies on induced antibodies with defined idiotypic specificities. I. The heavy chains of anti-p-azophenylarsonate antibodies from A/J mice bearing a cross-reactive idiotype.

Amino acid sequence analysis has been performed on three groups of heavy (H) chains of A/J mice. H chains derived from unimmunized animals were compared to anti-p-azophenylarsonate (anti-Ar) antibodies which were further subdivided into those possessing and those depleted of a cross-reacting idiotype (CRI). It was found that anti-Ar antibodies bearing the CRI are homogeneous through the first hypervariable region of the H chain. The same sequence was obtained for pooled antibody isolated from the ascites fluid of 18 A/J mice or from a single mouse. The H chains appear to belong to a minor V-H subgroup. In the first 30 positions Anti-Ar antibodies depleted of the CRI had the same sequence as those containing the CRI (with small amounts of heterogeneity at some positions), but contained a mixture of sequences in the first hypervariable region of the H chain. These studies indicate that antibodies with similar specificity and with identical framework sequences, but which differ in their hypervariable regions, contain different idiotypic determinants, and support the concept that the idiotypic determinants reside primarily within hypervariable regions.

Amino Acid Sequence↗
PubMed1975

Transplantable immunoglobulin-secreting tumors in rats. VI. N-terminal sequence variability in LOU/C/Wsl rat monoclonal heavy chains.

Most of the spontaneous ileocecal immunocytomas of LOU/C/Wsl strain rats secrete large amounts of monoclonal immunoglobulins. Amino acid sequence studies were undertaken on the heavy chains of 13 of these proteins and on pooled heavy chains from LOU rats to define the structural variability in the amino terminal region of the rat heavy chain. Characteristic VHIII sequences were found in both the myeloma proteins and the heavy chains from the pool. The data confirm previous conclusions concerning the rat VHIII subgroup that had been derived from studies of pooled heavy chains from Sprague-Dawley rats. In particular phylogenetically associated residues, identical to those previously determined in the Sprague-Dawley pool, were found in the LOU/C/Wsl rat myeloma proteins. There were two unexpected findings: 1) hypervariability at position 16 of the rat VHIII myelomas as contrasted with more than 90% glycine in the pool, and 2) a striking homology of one rat myeloma heavy chain with the variable region of the MOPC 315 mouse alpha-chain. The findings show that the rat myeloma system provides useful proteins for sequence analysis but indicate that some sequence pattern differences can be detected between the myeloma proteins and pooled immunoglobulins from this species.

Amino Acid Sequence↗
PubMed1975

Distribution and association of heavy and light chain variable region subgroups among human IgA immunoglobulins.

A series of randomly selected human IgA myeloma proteins were examined for the presence of the VHIII subgroup as defined by the possession of an unblocked amino terminal amino acid and characteristic linked residues along the heavy chain. Blocked heavy chains were classified as VHB proteins. The data showed that 20 of 30 such random alpha chains (67%) were classifiable as members of the VHIII subgroup. Similarly, 75% of heavy chains isolated from pools of normal serum IgA contained a VHIII variable region. The pattern stands in marked contrast to the situation in human IgG proteins where approximately 20% of heavy chains from both pools and myeloma proteins are VHIII. There was thus a clear divergence of the pattern of variable region: constant region association between these two classes of immunoglobulin. Some more limited data were obtainable for the light chains of the IgA myeloma proteins. Certain predilections for light chain subgroup:heavy chain subgroup (VHIII or VHB) associations were discernable, but more data are required for definite conclusions. Overall, this study suggests that although the pool of available variable region sequences is indeed shared among human IgA and IgG proteins, the partitioning is not exactly equivalent between the two immunoglobulin classes. The pattern is particularly apparent at present for the VHIII subgroup which comprises approximately 70% of human alpha chains and only about 20% of human gamma chains.

Amino Acid Sequence↗