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Biomedical subjects

M Potter

Publications and source records attributed to M Potter.

At least 289 records · Page 16Linked to original sources
PubMed1977

Restriction in the immune response to flagellar proteins in inbred mice.

Anti-idiotypic sera prepared in both AL/N mice and rabbits identify specificities common to the IgA MOPC 467 myeloma protein and day-7 affinity-absorbed antibodies to Salmonella milwaukee polymerized flagellin (S. mil-POL) raised in BALB/c and C57BL/Ka mice. Isoelectric focusing (IEF) of reduced and alkylated BALB/c anti-S. mil-POL gave a banding pattern of L and H-chains identical to MOPC 467. C57BL/Ka anti-S. mil-POL had a similar L-chain pattern but a different H-chain pattern. Both BALB/c and C57BL/Ka contain predominantly IgA. The IEF patterns in the two strains are consistent with a monoclonal response at day 7.

Animals↗
PubMed1977

Idiotypes on galactan binding myeloma proteins and anti-galactan antibodies in mice.

Antibodies with specificity for beta1,6 linked D-galactoses were induced in mice by immunization with gum ghatti. Idiotypic antisera were prepared in rabbits and mice by immunization with 8 BALB/c IgA(k), beta1,6D-galactan binding myeloma proteins (beta6GALBMP). Two kinds of idiotypic sera were obtained: cross-specific sera that reacted with two or more beta6GALBMP but not other BALB/c myeloma proteins, and individual idiotypic sera that reacted with only the beta6GALBMP used in the immunization. Antibodies with specificity for beta1,6 linked D-galactans shared cross-specific idiotypes with beta6GALBMP. Only one of seven individual idiotypes associated with beta6GALBMP was found on galactan antibodies. Since all beta6GALBMP thus far have the same Vk and VH isotope composition the results indicate an extensive heterogeneity among galactan-binding immunoglobulins in BALB/c mice. It is speculated that some of this diversity may arise from somatic rather than germ line gene mutations.

Animals↗
PubMed1977

Effect of particle number on lung perfusion images: concise communication.

Twelve normal mongrel dogs were injected with decreasing numbers of 99mTc-labeled macroaggreagated albumin particles (99mTc-MAA), and lung images were recorded using both parallel-hole and pinhole collimators. The quality of normal lung images was found to decrease with decreasing numbers of injected radiolabeled particles (from 10,000 to 250 particles per injection). The quality was unaffected by adding carrier MAA. The minimum number of particles compatible with a good-quality image of the normal human lung is approximately 60 radiolabeled particles per gram of lung.

Animals↗
PubMed1976

The requirement of an adherent cell substratum for the growth of developing plasmacytoma cells in vivo.

The intraperitoneal injection of pristane (2,6,10,14-tetramethylpentadecane) produces an environment conductive to primary plasmacytoma growth in as few as 3 days. After pristane injection, the total free peritoneal cell population increases from a normal value of 1.55 X 10(6) to 5.28 X 10(6) and remains at this elevated level for at least 50 days. The adherent peritoneal cell population, composed of both mononuclear cells and polymorphonuclear leukocytes, is the primary source of this increase. In the pristane-conditioned peritoneum, these cells rapidly form a chronic granuloma on the peritoneal connective tissues. Daily subcutaneous treatment of mice with 0.5 mg of hydrocortisone beginning simultaneously with pristane injection prevents the increase in the peritoneal cell population, granuloma formation, d the production of a conditoned environment. In mice treated with hydrocortisone beginning 3 days after pristane injection, however, neither the peritoneal cell increase nor the production of a conditioned environment is prevented. The intraperitoneal injection of thioglycolate medium at 4-day intervals produces an elevation of the free adherent peritoneal cell population similar to pristane, but does not produce a granuloma or a conditioned environment. The intraperitoneal transfer of thioglycolate-induced adherent peritonel cells to mice treated with pristane and hydrocortisone simultaneously restores the production of a conditioned environment. These findings indicate that the adherent peritoneal cell population is responsible for the conditioning effect, and that the establishment of a resident population of these cells is necessary to produce conditioning.

Alkanes↗
PubMed1976

Subunit interactions in mouse myeloma proteins with anti-galactan activity.

The interactions among the subunits of a unique set of mouse myeloma proteins having specificity for beta-D-(1,6) galactans has been studied by making homologous and heterologous recombinants of heavy and light chains. The recombinations were carried out by mixing together the desired heavy and light chains that had been separated on a Sephadex G-100 column in urea-acetic acid and renaturing the chains at near neutral pH. One homologous and six heterologous recombinants have been prepared. All the recombinants prepared possessed a four-chain native-like structure. The ligand binding activity and idiotypic specificity of the homologous recombinant were essentially indistinguishable from those of the original native protein. All the heterologous heavy-light chain combinations also led to the regeneration of functional binding sites. The affinity of the heterologous recombinants towards various galactose ligands was comparable to those of the native molecules. Furthermore, the ligand binding affinity of the recombinants was almost invariably closer to the Ka of the original protein that had a higher affinity. Idiotypic specificity of the heterologous recombinants paralleled that of the original protein that had contributed the heavy chain.

Animals↗
PubMed1976

Size differences among immunoglobulin heavy chains from phosphorylcholine-binding proteins.

The entire sequences of the heavy chain variable regions of M167 and TEPC 15 (phosphorylcholine-binding myeloma proteins of BALB/c origin) have been determined. These sequences are compared with the phosphorylcholine-binding protein M603. T15 differs from M603 at four positions, all of which are located in antigen-binding complementarity regions. M167, in addition to having differences in the complementarity regions, also has five substitutions in the conserved framework portion of the variable region when compared to T15 and M603. Each of the three proteins has a different length in the third complementarity region. It is unlikely that complementarity regions of different lengths associated with similar framework regions could be generated by proposed mechanisms of somatic mutation which are generally limited to point mutations. It appears more likely that these products are directly encoded by different structural germ line genes.

Amino Acid Sequence↗
PubMed1976

Murine plasma cells secreting more than one class of immunoglobulin heavy chain. I. Frequency of two or more M-components in ascitic fluids from 788 primary plasmacytomas.

Primary ascites from 778 consecutive plasmacytomas of BALB/c and other mouse strains were tested by immunoelectrophoresis for the presence of paraproteins belonging to different immunoglobulin classes. gammaA was produced by 338 tumors: gamma Gs (gamma 1, gamma 2a, gamma 2b, or gamma 3) by 163 tumors; and gamma M by seven tumors. Free kappa- or lambda-typed light chains were produced by 14 tumors, and no detectable paraprotein was produced by 202 tumors. Two or more paraproteins were detected in the primary ascites of 54 plasmacytomas. Evidence suggests that in most cases, the multiple paraproteins are produced by simultaneously occurring, independent plasma cell tumors. However, two tumors, SAMM 368 and TEPC 609, produced two paraproteins for over 30 generations in transplantation. This finding implies that single clones of plasma cells have the capacity to produce more than one class of immunoglobulin.

Animals↗
PubMed1976

Localized deletion-insertion mutations: a major factor in the evolution of immunoglobulin structural variability.

New and previously published amino acid sequences of mouse Vk chains completed to Trp35 were examined. This sequence includes a framework loop from NH2 to Cys23 and an antigen contacting complementarity region L1 which lies between Cys23 and Trp35. There are many different sequence variations from NH2 to Cys23 among BALB/c mouse Vk chains indicating multigenic control. Coordinately there is a remarkable structural heterogeneity of L1 size and sequence. Thus far chains with the same NH2-Cys23 sequence have similar sized L1, which suggests a close relationship between L1 size and characteristic NH2-Cys23 sequence. In this multigenic system selection for chains with size variations in L1 appears to have occurred. The mutational process that inserts or deletes triplets in this region is thought to be exploited in the derivation of new useful structural genes.

Amino Acid Sequence↗
PubMed1976

Idiotype of inulin-binding antibodies and myeloma proteins controlled by genes linked to the allotype locus of the mouse.

The serum from non-immunized mice of strains BALB/c, C58, A/He, and RIII contained hemagglutinins for stearoyl inulin-coated SRBC. Immunization with bacterial levan slightly elevated these titers. These same sera also carried cross-specific idiotypic determinants (IdX) that are associated only with inulin-binding myeloma proteins (INBMP) of BLAB/c mice. Three InuldX specificities, A, B, and G, were identified. The InuIdX phenotypes of strains BALB/c, C58, and A/He were InuIdXA+B+G+; strain RIII was InuIdX A+B-G+; strain C57BL/6, C57BL/10, DBA/2, AKR and NH were A-B-G-. Strains CBA, C3H, PL, and C57L could not be typed because of low and inconsistent levels of InuIdX and anti-inulin hemagglutinins. The InuIdXA+B+G+ phenotype was used as a genetic marker in immunoglobulin congenic strains CB-20, BAB-14, and BC-8 and in Bailey RI strains which are derived from crosses of BALB/c (InuIdXA+B+G+) and C57BL/ka or C57BL/6, respectively (InuldXA-B-G-). Linkage of the IdXA+B+G+ to the BALB/c a allotype locus was demonstrated. In addition, the InuldXA+B+G+ marker was used as a phenotype in an analysis of 168 first generation backcorss progeny (C57BL X (C57BL X BALB/c) F). Linkage of the marker to the BALB/c allotype was found again. Two proven recombinant mice having the C57BL a allotype and the InuIdxA+B+G+ markers were identified and progeny tested. Four other potential crossover types are still being progeny-tested.

Animals↗
PubMed1975

Multiple individual and cross-specific indiotypes on 13 levan-binding myeloma proteins of BALB/c mice.

13 leven-binding myeloma proteins (LBMP) of BALB/c origin were classified into two groups with different binding specificities; one group of 11 proteins bound beta2 leads to 1 fructosans, a second group of two proteins bound fructosans probably of beta2 leads to 6 linkage. Anti-idiotypic sera prepared to 10 of the proteins in the appropriate strains of mice identified numerous idiotypic determinants. Each protein used for immunization had its own unique individual idiotypic specificities (IdI) and in addition most of the proteins carried two-nine cross-specific or shared idiotypes (IdX) that were found only among LBMP, and not found in 106 non-LBMP. Most of the IdX determinants and only four of the IdI determinants of the beta2 leads to 1 fructosan binding group were located in the antigen-binding site. The multiplicity of antigenic differences in this functionally related group of immunoglobulins reveals an unexpected degree of heterogeneity in V-regions that appears to be unrelated to binding.

Animals↗
PubMed1975

An IgM Waldenström with specificity against phosphorylcholine.

Anti-phosphorylcholine specificity has recently been shown to occur with relatively high incidence among IgA myeloma proteins secreted by oil-induced plasma cell tumors in the BALB/c strain of mice. A similar screening of human myeloma sera indicates that in man activity for phosphorylcholine is very rare. Among 904 human sera containing IgG, IgA, and IgM M-components only one reacted with phosphorylcholine-containing antigens. This serum was obtained from a patient with macroglobulinemia Waldenström. The active homogeneous protein could be isolated by affinity chromatography using a Sepharose-phosphorylcholine immunoadsorbent. It was an IgM immunoglobulin; the light chains were of the kappa type. The association constant for the reaction with phosphorylcholine was homogeneous and equalled 6.4 times 10-4 l. mol-1 at 25 degrees and 8.1 times 10-4 l. mol-1 at 2 degrees, indicating that the binding reaction is exothermic. The valences of the pentamer IgM, the 7S IgM subunit produced by reduction with cysteine, and the Fab fragment obtained by cleavage with papain were 10, 2, and 1, respectively. By all criteria available for antibody-like binding such as high specificity, restriction of the binding sites to the Fab part of the molecule and correct stoichiometry this IgM exhibits the fundamental characteristics associated with conventionally induced antibodies.

Aged↗
PubMed1975

Structural, functional, and idiotypic characteristics of a phosphorylcholine-binding IgA myeloma protein of C57BL/ka allotype.

An IgA phosphorylcholine (PC)-binding myeloma protein with IgCH allotypic determinants different from those of BALB/c mice is characterized. The myeloma, CBPC 2, was induced in the CB-20 strain of mice which is congenic to BALB/c but differs from it by carrying the A15 allotypic determinant of C57BL/ka mice. Sequence analysis of the CBPC 2 light chain through the first hypervariable region, as well as isoelectric point analysis, show that this chain is indistinguishable from that of T15, a PC-binding myeloma protein of BALB/c origin. The heavy chains of CBPC 2 and T15 differ by only two amino acids (positions 14 and 16) through the first hypervariable region. As measured by inhibition of precipitation, both CBPC 2 and T15 have the same specificity for PC, glycerophosphorylcholine, acetylcholine, and choline. In addition, CBPC 2 possesses the binding site-associated idiotypic determinant which is present on T15. However, like normal or induced C57BL/6 anti-PC antibody, it does not possess the nonbinding site idiotypic determinant.

Amino Acid Sequence↗
PubMed1975

Isolation of type-C viruses from the Asian feral mouse Mus musculus molossinus.

N-tropic and xenotropic type-C viruses have been isolated from the wild Asian mouse subspecies M. musculus molossinus. By host range, morphologic and some immunologic criteria these viruses appear closely related to the previously studied murine type-C viruses isolated from highly inbred laboratory strains of mice.

Animals↗