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Biomedical subjects

M Potter

Publications and source records attributed to M Potter.

At least 253 records · Page 14Linked to original sources
PubMed1981

A monoclonal antibody that defines an idiotope with two subsites in galactan-binding myeloma proteins.

An IgG1 monoclonal antibody HyX24-14 was derived from A/J mice that were immunized with the IgA XRPC24 (X24) galactan binding myeloma protein (GalBMP) of BALB/c origin by the Kohler-Milstein hybridoma technology. HyX24-14 specifically binds some but all GalBMP. Different patterns of binding using a panel of nine Gal BMP were found, depending upon the concentration of antibody and the antigenic target. From molecular models and amino acid sequence data, ti was proposed that the idiotope defined by HyX24-14 had two subsites, each of which appeared to be able to bind independently to the antibody.

Animals↗
PubMed1981

Immunochemical specificity of the combining site of murine myeloma protein CAL20 TEPC1035 reactive with dextrans.

The immunochemical specificity of the combining sites of murine myeloma protein CAL20 TEPC1035 was studied by quantitative precipitin and precipitin inhibition assays. Myeloma protein CAL20 TEPC1035 precipitated with only three dextrans, B1355S4, B1498S, and B1501S, with high proportions of alpha(1 leads to 3) linkages, but not with any other dextrans, glycogen, and pullulan. Inhibition tests with various sugars show that the combining site of myeloma protein CAL20 TEPC1035 is most complementary to panose, a trisaccharide DGlc alpha(1 leads to 6)DGlc alpha(1 leads to 4)DGlc. Panose was 3.3 times more potent than a tetrasaccharide DGlc alpha(1 leads to 6)DGlc alpha(1 leads to 4)DGlc alpha(1 leads to 4)DGlc and 8, 23, 42, > 42 times more active than maltose, nigerose, isomaltose, and kojibiose, respectively. These findings were paralleled by their binding properties as determined by affinity electrophoresis. The association constants (Ka) of these three dextrans to myeloma protein CAL20 TEPC1035 ranged from 3.8 X 10(3) ml/g to 5.02 X 10(3) ml/g. The association constant of inhibitor (Kia) of panose was 8.19 X 10(3) M-1. Myeloma protein CAL20 TEPC1035 is an antidextran with specificity different from those of other murine myeloma antidextrans and from human antidextrans reported previously and its combining site size is at least as large as a trisaccharide. The binding constant of methyl alpha-D-glucoside (7.2 X 10(2)) was 73% of that of panose and comparable to that of myeloma protein W3129 (9.4 X 10(2)) with a cavity-type site and 600 times lower (1.6 X 10(0)) for QUPC52 with a groove type site, indicating that the terminal nonreducing residue is held in a cavity. Inhibition data with various alpha(1 leads to 4)-linked oligosaccharides also indicate that the internal portions of these inhibitors may react directly with a portion of the combining site. These findings suggest that myeloma antidextran CAL20 TEPC1035 has a partial cavity-type combining site in which the terminal nonreducing dGlc alpha(1 leads to 6) moiety is held in a cavity with the other two sugars forming a groove. However, oligosaccharides with one or more alternating [leads to 3DGlc alpha(1 leads to 6)DGlc alpha(1 leads to 3)DGlcl leads to] units with and without terminal nonreducing DGlc alpha(1 leads to 6) or DGLc alpha(1 leads to 3) side chains remain to be tested to determine whether structures known to be present in the three dextrans which precipitate CAL20 TEPC1035 may not prove to be more active than panose.

Animals↗
PubMed1981

Plasma membrane enzymes in BALB/c lymphomas with either T or B cell properties, I. 5'-Nucleotidase.

Comparison of membrane bound 5'-nucleotidase activity has been made in crude extracts and plasma membrane fractions from Abelson virus transformed lymphomas, IgM, IgG and IgA producing plasmacytomas and from thymomas with different surface antigen markers. 5'Nucleotidase activity was characterised by the following criteria : 1) optimal pH for enzyme activity, 2) specificity of 5'AMP as a substrate at the optimal pH, 3) specific inhibition of the enzyme by alpha beta methylene ADP, 4) inhibition by EDTA. 5'-Nucleotidase was found to be present on the following B cells : Abelson virus transformed lymphomas, plasmacytomas and LPS-stimulated blasts from nu/nu spleens. The enzyme was also found in one thymoma Lut 13, but it was absent from all the other thymomas studied. A possible relationship between 5'-Nucleotidase and purine metabolism in lymphocyte subpopulations is suggested by the results.

5'-Nucleotidase↗
PubMed1981

IgD-secreting murine plasmacytomas: identification and partial characterization of two IgD myeloma proteins.

We have used an immunofluorescence inhibition assay to identify 2 BALB/c plasmacytomas, TEPC-1017 and TEPC-1033, that secrete large quantitites of IgD. Both TEPC-1017 and TEPC-1033 myeloma proteins bound to anti-kappa as well as hybridoma and heterologous anti-delta antibodies, but not to anti-mu, gamma, alpha, or lambda antibodies. Both myeloma proteins were purified by (NH4)2SO4 precipitation, ion exchange chromatography, gel filtration, and Staphylococcus aureus Protein A absorption. These IgD kappa myeloma proteins were used to prepare affinity purified rabbit antibodies to delta-chain and the TEPC-1017 and TEPC-1033 idiotypes. Native TEPC-1017 and TEPC-1033 both had mobilities between those of mouse IgA kappa dimers and trimers when analyzed by polyacrylamide gradient gel electrophoresis. Both IgD myeloma proteins broke down under mild reducing conditions into subunits with electrophoretic mobilities slightly slower than those of an IgA kappa monomer. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of reduced TEPC-1017 and TEPC-1033 demonstrated kappa-chains and heavy chains that co-migrated with alpha chain. These data suggested that secreted IgD contains 2 delta 2 kappa 2 subunits that are linked by an easily reducible disulfide bond. The kappa-chains of IgD secreted by TEPC-1017 and TEPC-1033 have apparent m.w. of approximately 63,000 daltons, whereas the apparent m.w. of intracytoplasmic delta-chain, intracytoplasmic delta-chain synthesized in the presence of tunicamycin, and the cellfree translation product of TEPC-1017 delta-chain mRNA are 54,000, 43,000, and 44,000 daltons, respectively. This is compatible with the interpretation that the delta-chain peptide has a leader sequence and is N-glycosylated during or shortly after peptide synthesis and is glycosylated further shortly before IgD secretion.

Animals↗
PubMed1981

Immunoglobulin heavy chains from anti-inulin myeloma proteins: evidence for a new heavy chain joining segment.

Immunoglobulin heavy chains have been shown to be encoded by at least 3 widely separated genetic elements, designated variable (V), diversity (D), and joining (J), which undergo rearrangement during somatic differentiation to produce the active gene form. The D segment codes for a portion of the 3rd hypervariable region and thus potentially contributes significantly to structural diversity in this portion of the molecule. Heavy chains from anti-inulin proteins are unusual in that they essentially lack a 3rd hypervariable region. Thus, if a D segment exists in these proteins, it is extremely short, possibly 1 to 2 amino acids, and more likely serves a framework function rather than introduces structural diversity in the 3rd hypervariable region. We have completed the heavy chain variable region amino acid sequence from proteins AMPC1 and T957 bringing to 6 the number of complete sequences from this group. All of these proteins lack a 3rd hypervariable region. In addition, substitutions are found within the J segments of AMPC1 and T957, which are unlikely to be generated by the recombination event. The occurrence of Pro at position 105 in both of these J segments in contrast to the Gln found in all other heavy chains using this J segment suggests the possible existence of a previously unidentified J segment gene.

Amino Acid Sequence↗
PubMed1981

Mouse myeloma proteins with lambda 2 and lambda 3 light chains.

Serum and ascites fluid from mice bearing 260 different myeloma tumors were screened serologically for myeloma proteins having light chains like that of L315, the lambda 2 chain produced by myeloma MOPC-315. Four proteins, made by myelomas TEPC-952, CBPC-49, ABPC-72, and SAPC-15, were identified. Their light chains were essentially indistinguishable serologically from L315, and each of them also yielded the characteristic C-terminal amino acid (leucine) and C-terminal tryptic peptide of L315. However, amino acid sequences and other findings reported elsewhere have revealed that although the light chain of TEPC-952 is indeed a lambda 2 chain, the light chains of the others (CBPC-49, ABPC-72, and SAPC-15) represent another, slightly different type of light chain, which has been designated lambda 3.

Amino Acids↗
PubMed1981

Genetics of susceptibility to pristane-induced plasmacytomas in BALB/cAn: reduced susceptibility in BALB/cJ with a brief description of pristane-induced arthritis.

BALB/cAn and BALB/cJ inbred strains of mice were separated 43 yr ago, but are still very closely related because they carry the same allelomorphs at many loci. When injected 3 times i.p. with 0.5 ml of pristane (2, 6, 10, 14 tetramethylpentadecane) 11% of strain BALB/cJ develop plasmacytomas in contrast to 61% in BALB/cAn sublines. BALB/cJ first injected with pristane as neonates also developed a reduced number of plasmacytomas as compared with BALB/cAn. About 20% of pristane-treated BALB/cAn and 70% of pristane-treated BALB/cJ develop arthritis, which first appeared in the ankle joints after a latent period of 4 mo or more.

Animals↗
PubMed1981

Allelic forms of anti-phosphorylcholine antibodies.

Anti-idiotype antisera were prepared to 2 phosphorylcholine (PC) binding myeloma proteins, T15 of BALB/c origin and C3 of C57BL origin. These antisera were shown to recognize the respective determinants on induced anti-PC antibodies in the 2 parental strains. Genetic analysis of these V region markers in backcross progeny of (BALB/c X C57BL/6) X BALB/c demonstrated that the 2 determinants segregated as simple Mendelian alleles linked to the allotype locus. The genetic data are consistent with previously reported structural studies suggesting the allelic nature of the T15 and C3 heavy chain variable regions. The expression of the T15 and C3 antigenic determinants in Ig congenic and recombinant inbred strains derived from BALB/c-C57BL/6 crosses further supports the concept of allelism although a single exception was observed. Strain distribution analysis has indicated the potential existence of other alleles of the T15 gene in addition to C3.

Alleles↗
PubMed1980

Turtle-associated salmonellosis in the United States. Effect of Public Health Action, 1970 to 1976.

We examined the effect of state and federal legislative actions on the incidence of human salmonellosis associated with pet turtles. Using the Salmonella Surveillance System of the Center for Disease Control, we identified Salmonella serotypes that were and were not specifically turtle associated. From 1970 to 1976, there was a 77% reduction in frequency of turtle-associated serotypes and no consistent trend among non-turtle-associated serotypes. Decrease in frequency of turtle-associated serotypes correlated best with decrease in total production of pet turtles. Reduction in turtle-associated sertotypes temporally correlated with an 18% reduction in frequency of salmonellosis in children, aged 1 to 9 years. Frequency of turtle-associated serotypes rapidly fell in states importing turtles, in contrast to states producing them. Continued although infrequent occurrence of salmonellosis in children with pet turtles counsels against relaxing legislation concerned with its control.

Animals↗
PubMed1980

Cytogenetic studies on IgA/lambda-producing murine plasmacytomas: regular occurrence of a T(12;15) translocation.

Seven IgA/lambda-producing murine plasmacytomas had the 12;15 translocation, previously found in IgA/kappa-producing plasmacytomas, and lacked the rcpT(6;15) translocation, also found in some kappa producers. The results suggest that the generation of the 12;15 translocation is an important, perhaps essential event during the genesis of plasmacytomas. The possibility that the distal region of chromosome 15 may contain a "supergene" area involved with the differentiation and/or normal responsiveness of various types of lymphoreticular cells, must be seriously considered on the basis of the present and previous evidence on plasmacytomas, as well as the extensive evidence now available on the role of chromosome 15-changes in the genesis of murine lymphomas. The involvement of chromosome 12 is of interest in view of the fact that it is known to carry the heavy-chain immunoglobulin determinants.

Animals↗
PubMed1980

Mouse immunoglobulin D: construction and characterization of a cloned delta chain cDNA.

TEPC 1017 is a BALB/c plasmacytoma that synthesizes IgD in large enough amounts to permit the isolation of mRNA for mouse delta chains. cDNA has been prepared from this mRNA, and an 880-base-pair fragment of it has been cloned by recombinant DNA techniques. The hybridization selection technique has been used to show that this cDNA clone specifically binds only mRNA that can be translated into immunoprecipitable delta chains. the sequence of a portion of this clone has been determined and, when translated, shows homology with the C delta 3 of a human myeloma protein. Using this cDNA clone as a probe, we have found that several different-sized delta RNAs are present in TEPC 1017 and in another IgD-secreting plasmacytoma, TEPC 1033.

Animals↗
PubMed1980

kappa Chain joining segments and structural diversity of antibody combining sites.

Immunoglobulin kappa light chains are coded for by at least three distinct gene segments designated variable, joining, and constant. The joining gene codes for the 13 amino acid segment linking the variable and constant regions. This peptide includes the last amino acid (96) in the third complementarity-determining region and thus could introduce structural diversity. We have determined the light chain variable region sequences from three myeloma proteins with beta(1,6)galactan-binding specificity, bringing to six the number of light chains sequenced from proteins demonstrating this specificity. Five of these have isoleucine at position 96 and the sixth tryptophan. This substitution appears to be accommodated with no significant change in association constant for a beta(1,6)galactan hapten. Additionally, as many as nine substitutions are found in both light and heavy chain complementarity-determining regions between members of this group although only minimal variations in hapten binding affinity are observed. The isoleucine found at position 96 in five of the kappa chains could not be coded for by any of the joining gene nucleotide sequences previously observed and would require a novel nucleotide sequence at the recombination site between variable and joining genes to produce the observed protein structure. Alternatively, there may exist joining gene segments not yet detected.

Amino Acid Sequence↗
PubMed1980

Allelic forms of the immunoglobulin heavy chain variable region.

The complete variable region sequence of the heavy chain from a phosphorylcholine-binding myeloma protein of C57/BL allotype has been determined. When this sequence was compared with the germ line-coded heavy chain variable region sequence of BALB/c phosphorylcholine-binding proteins, five differences were observed. Four of the substitutions were located in the framework portion of the variable region and the fifth in the "J" or joining segment. Two of the framework substitutions were found at positions 14 and 16. Previous studies have shown that heavy chains from all anti-phosphorylcholine antibodies induced in C57/BL mice have the same amino acids at positions 14 and 16 as the C57/BL myeloma protein described in this communication. It has therefore been concluded that these residues are encoded in the C57/BL germ line in contrast to two alternatives in the BALB/c genome. This finding, in addition to the 96% homology found between the C57/BL and BALB/c sequences, suggests that these structures represent allelic forms of an entire variable region.

Alleles↗