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M Parsons

Publications and source records attributed to M Parsons.

At least 127 records · Page 7Linked to original sources
PubMed1983

Genetic characterization of mouse immunoglobulin allotypic determinants (allotopes) defined by monoclonal antibodies.

We have generated a new series of monoclonal antibodies recognizing allotypic determinants on mouse IgG1, IgG2a, and IgG2b. In this communication we describe their reactivities with immunoglobulins of the inbred mouse strains. Comparison with serology charts indicates that many of these monoclonal antibodies detect allotypic specificities previously defined by conventional antisera; others define previously undescribed specificities. Strain and isotype distribution allows us to assign five new allotypic specificities to Igh-1 and three new specificities to Igh-3. In addition, on the basis of reactivity with the monoclonal antibodies, we have defined a new Igh haplotype in SWR/J mice, Ighp.

Alleles↗
PubMed1983

Structural characterization of mouse immunoglobulin allotypic determinants (allotopes) defined by monoclonal antibodies.

We have generated a new series of monoclonal antibodies recognizing allotypic determinants on mouse IgG1, IgG2a, and IgG2b. In this communication we describe their reactivity at the molecular level. A number of genetic specificities (as defined by reactivity with sera from inbred strains) were divided into subspecificities (allotopes) by these analyses. With the exception of one allotope located in the hinge region of Igh-1b, all other 23 allotopes examined were preserved upon reduction and alkylation of immunoglobulin antigens. To further analyze the role of immunoglobulin conformation in presenting the allotopes, we assayed their presence on mixed Igh-1a/Igh-4a heavy chain molecules. The Igh-1a determinants were maintained, but the Igh-4a determinants were lost. Taken together, our results indicate that genetic polymorphisms at the Igh loci generate an enormous antigenic complexity, much of which relies on tertiary and quaternary protein structure for expression.

Alleles↗
PubMed1983

Sequences homologous to the variant antigen mRNA spliced leader are located in tandem repeats and variable orphons in trypanosoma brucei.

We have examined the organization of genomic sequences homologous to the spliced leader of Trypanosoma brucei variant surface glycoprotein (VSG) mRNA, using a synthetic oligodeoxynucleotide probe. These sequences are highly reiterated in the trypanosome genome and most are located in 1.4 kb units arranged in a direct tandem repeat. However, some of the 1.4 kb sequences are dispersed from the cluster(s) of tandem repeats and are flanked by non-repeat DNA. The number and arrangement of these leader sequence orphons varies among different T. brucei stocks. Within the IsTat serodeme, the arrangement of three of four spliced leader orphons observed with Eco RV digestion was stable during a chronic infection and cyclic transmission through the insect vector. The fourth Eco RV orphon, however, undergoes rearrangement during antigenic variation and life-cycle differentiation.

Animals↗
PubMed1983

Molecular characterization of initial variants from the IsTat I serodeme of Trypanosoma brucei.

Variant surface glycoproteins (VSGs) were isolated from variant antigen types (VATs) of the IsTat 1 serodeme. Molecular weight and isoelectric focusing analysis demonstrate that seven early VSGs possess properties generally attributed to VSGs isolated from other trypanosome serodemes. Six of the seven VSGs characterized are distinct from one another, while two (D and 1) appear identical. The presence of VSG specific mRNA in corresponding VATs was demonstrated by in vitro translation of RNA from each of the VATs, followed by immunoprecipitation with homologous and heterologous antisera. Hybridization of VSG cDNA clones with RNA from each VAT confirm that VSG mRNA is present only in homologous VATs and verifies the transcriptional control of these VSG genes. The two VATs D and 1 express indistinguishable VSGs by a variety of biochemical criteria, as well as by reactivity with 24 monoclonal antibodies. The VSG mRNAs in VATs D and 1 also appear identical. However, this identity is not reflected at the genomic level. Data is presented which establishes that DNA rearrangements can occur around both expressed and non-expressed VSG genes without qualitatively affecting VSG gene expression.

Animals↗
PubMed1983

Genomic organization of Trypanosoma brucei variant antigen gene families in sequential parasitemias.

cDNA libraries were made from mRNA purified from each of seven sequentially isolated variant antigen types (VATs) of the IsTat 1 serodeme. Plasmids containing variant surface glycoprotein (VSG) sequences corresponding to each of the isolates were used in Southern analyses to examine the genomic organization of VSG nucleotide sequences. In most cases, cells expressing a given VSG were shown to have an extra copy of the corresponding VSG gene. In one case an expression-linked copy (ELC) was not detectable. VSG gene rearrangements not obviously correlated with the expression of homologous sequences were detected in four of six VSG gene families. Thus, even cDNAs which detected an ELC revealed additional genomic reorganization in regions flanking VSG sequences. The cells used to initiate the chronic infection expressed the same VSG as those isolated from the first parasitemia. The extent of genomic rearrangement observed between these two sequentially derived populations was comparable to that observed between any of the other serially derived VATs. Thus, within a short period of time and in the absence of detectable antigenic variation, the amount of genetic flux in sequences associated with VSG genes can be substantial.

Animals↗
PubMed1983

Human immunoglobulin allotypes: previously unrecognized determinants and alleles defined with monoclonal antibodies.

The highly polymorphic system of serologically defined genetic markers on human IgG heavy chains (Gm allotypes) is second only to the HLA complex in terms of the large number of determinants, alleles, and haplotypes that can be used for analyses of disease associations and other genetic studies. However, present typing methods are based on the use of anti-Gm antisera that are derived mainly from fortuitously immunized human donors, often requiring processing before use, and must be used in a hemagglutination-inhibition assay that cannot be used in typing for isoallotypic determinants (currently termed "non-markers"). In studies presented here, we describe an allotyping system that utilizes monoclonal antibodies in a "sandwich" modification of the solid-phase radioimmunoassay, which is capable of reliable quantitative typing of allotypic, isoallotypic, and isotypic immunoglobulin determinants. We show that these highly reproducible, easily disseminated, and essentially inexhaustible reagents can be used for rapid, sensitive, and quantitative Gm typing. Using this system we define two previously unrecognized Gm determinants, one of which, found to date only in Caucasians, is different from all known Gm markers and thus defines previously unrecognized alleles and haplotypes. The other determinant co-segregates with the conventional G3m(b1) marker but is distinct from that marker on serological grounds. The successful preparation of mouse monoclonal antibodies that detect human Gm allotypic differences and the development of an assay system capable of typing isoallotypic as well as allotypic determinants opens the way to further dissection and application of this rich genetic system.

Alleles↗
PubMed1982

Imposed termination of psychotherapy and its relation to death and mourning.

For the psychotherapist unilaterally to impose a termination date to therapy is a manoeuvre not often discussed; but with some patients it may be the only way of forcing critical issues into the open. The patient's position is then analogous to that of a bereaved mourner or someone with a terminal illness, and a sequence of responses can be observed identical to that which occurs in those cases. A detailed clinical example illustrates this. There appears to be a specific developmental task common to all such situations which is called forth by them. Subjecting a patient to this is a drastic measure; the therapist's difficulty in deciding whether to do so is considered in relation to transference and counter-transference.

Adult↗
PubMed1982

Monoclonal antibody defining a Burkitt's lymphoma-associated antigen detects carbohydrate on neutral glycolipid.

Monoclonal antibody 38.13 detects an epitope presented on Burkitt's lymphoma cells that has not been detected on other lymphoid tissues or tumors. The biochemical nature of this Burkitt's lymphoma-associated antigen was investigated by staining inhibition assays. Indirect immunofluorescence and fluorescence-activated cell sorter analysis show that antibody 38.13 reacts with a protease-resistant structure present among the hydrophobic components extracted with chloroform-methanol from the Ramos Burkitt's cell line. These components were further separated by ion-exchange chromatography and activity resides in the unbound (neutral) fraction. The staining antibody is specifically absorbed when preincubated with D-galactose, and to a lesser extent with N-acetyl-galactosamine. Therefore, 38.13 appears to recognize a determinant of carbohydrate nature, which is carried on a neutral glycolipid.

Absorption↗
PubMed1982

New immunoglobulin IgG allotypes and haplotypes found in wild mice with monoclonal anti-allotope antibodies.

Sera from 156 wild mice (Mus musculus L.) collected from parts of Eurasia, Northern Africa, and the Americas were tested in solid-phase radioimmunoassays for reactivity with 20 monoclonal anti-allotope antibodies directed against gene products of the Igh-1, Igh-3, and Igh-4 loci. Most of the wild mice have Igh phenotypes similar to those of inbred strains or heterozygotes thereof, but frequently the wild mice showed unique combinations of allotypes on a given chromosome (haplotypes) not seen in inbred strains. We found new allotypes of the Igh-1 and Igh-4 loci. Mice from three regions (Poland, Taiwan, and Japan) possess combinations of allotypes indicating that recombination, gene conversion, or other gene duplication events have occurred in portions of the Igh constant region gene complex. Most interestingly, sera of three mice from Egypt possess immunoglobulin molecules appearing to result from an intragenic recombination event involving either Igh-1d or Igh-3d with Igh-1b. Two mice from Pakistan and one from Seychelles Island in the Indian Ocean also showed similar unusual phenotypes. These mice possess two CH2 IgH-1b and two CH2 Igh-1a/CH2 Igh-1d determinants, suggesting that these variant immunoglobulin arose from recombinations within the CH2 domain.

Animals↗
PubMed1981

A monoclonal mouse antiallotype antibody reacts with certain human and other vertebrate immunoglobulins: genetic and phylogenetic findings.

A new mouse monoclonal antibody, 18.1, recognizes an allotypic determinant on mouse IgG1 of the "a" allotype. We found that this alloantibody reacts with immunoglobulins of evolutionarily distant vertebrate species including man, and with only certain isotypes or allotypes in some of these species. Most mammalian sera are reactive, except those from lagomorphs, marsupials, and monostremes. Avian and reptilian sera are also positive, while the amphibian and fish sera tested were negative. In human sera, 18.1 detects the isotypic marker on IgG2 and an allotypic marker on IgG3. This reactivity parallels the distribution of the Gm non-g determinant. These findings are discussed in relation to the phylogeny of IgG and its subclasses.

Amphibians↗
PubMed1980

Cystic fibrosis alpha 2-macroglobulin protease interaction in vitro.

alpha 2-Macroglobulin was purified from plasma of five cystic fibrosis patients and five normal controls. SDS gel electrophoresis of native alpha 2-macroglobulin from cystic fibrosis patients and normal donors showed identical subunit molecular weights, as did trypsin cleavage products. Cystic fibrosis and control alpha 2-macroglobulins were indistinguishable by isoelectric focusing and exhibited appropriate shifts in isoelectric point following binding of trypsin. The trypsin-binding capacities of control and cystic fibrosis alpha 2-macroglobulins did not differ, nor did the esterolytic activity of the trypsin-alpha 2-macroglobulin complexes.

Adolescent↗
PubMed1980

The risk of breakdown during outpatient psychotherapy.

Patients accepted for psychotherapy were surveyed with regard to features of their history and symptoms which have been believed to increase the likelihood of breakdown during therapy. These beliefs were not found to be justified. A positive but brief history of previous psychiatric treatment did appear to make breakdown more likely. These findings can also be applied to selection of patients for psychotherapy.

Ambulatory Care↗
PubMed1980

Competition for trypsin binding between alpha 2-macroglobulin and antitrypsin antibodies in cystic fibrosis.

As previously reported, Tblg, especially TblgG, have been identified in CF patients, and their production appears to be elicited by the porcine trypsin ingested daily by most CF patients. We have measured by IP assay the binding of 125I-trypsin to a alpha 2M and TblgG in plasma of CF patients and controls. Our results do not confirm previous reports of decreased trypsin binding to alpha 2M in whole CF plasma with respect to controls. We have shown, however, that antitrypsin antibodies from CF patients or from rabbits immunized against trypsin compete with alpha 2M for binding with trypsin. This competition can cause apparent decrease of trypsin binding to alpha 2M in vitro.

Antibodies↗
PubMed1979

Binding of 125I-labeled proteinases to plasma proteins in cystic fibrosis.

Samples of plasma or serum from 53 cystic fibrosis (CF) patients, 90 relatives of CF patients , and 159 controls have been incubated with porcine or bovine 125I-trypsin, electrophoresed on polyacrylamide gel, and autoradiographed. In these individuals, the main binding protein for 125I-trypsin has been shown to be alpha 2-macroglobulin (alpha 2M). Using this method of analysis, no difference in electrophoretic migration of 125I-trypsin-alpha 2M complexes has been observed between CF and control individuals. However, trypsin binding to IgG has been observed in 80% of CF patients, 30% of their mothers, 3% of controls, and in two patients affected with pancreatitis. These trypsin binding immunoglobulins are called TbIg, and specifically, Tb1gG when referring to the G class. Experimental evidence indicates that binding of trypsin to IgG occurs through the Fab portion of the molecule. Tb1gG must be antibodies most probably induced by the exogenous trypsin ingested daily by most CF patients (and by patients affected with chronic pancreatitis). Antibodies against porcine pancreatic elastase have been observed using the same analysis, but not as frequently as Tb1g.

Arginine↗