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Biomedical subjects

M A Lynes

Publications and source records attributed to M A Lynes.

31 records · Page 2Linked to original sources
PubMed1990

Immunological characterization of plant ornithine transcarbamylases.

Pea (Pisum sativum L.) ornithine transcarbamylase (OTC) antisera were used to investigate the immunological relatedness of several plant and animal OTC enzymes. The antisera immunoprecipitated OTC activity in all monocot and dicot species tested, and sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis of immunoprecipitated protein revealed monomeric proteins ranging from 35,200 to 36,800 daltons in size. Pea OTC antisera did not recognize mammalian OTC protein. OTC activity and protein levels detected on sodium dodecyl sulfate polyacrylamide gel electrophoresis immunoblots from homogenates of green leaf, etiolated epicotyl and cotyledon, and root tissues of pea were poorly correlated. This might result from differences in amounts of enzymatically active OTC protein in the homogenates. Alternatively, the antisera may fail to recognize different isozyme forms of OTC, which have been reported for some plant species. A putative cytosolic precursor OTC (pOTC) polypeptide exhibiting and Mr = 39,500 to 40,000 daltons was immunoprecipitated from in vitro translation mixtures of total pea leaf poly(A)+ RNA. The size of the pOTC polypeptide, as compared with mature OTC monomer (36,000 daltons), suggests that a 4 kilodalton N-terminal leader sequence, like that responsible for mitochondrial targeting of the mammalian enzyme, may be involved in organellar import of the plant enzyme.

Animals↗
PubMed1985

Characterization of a Q subregion gene in the murine major histocompatibility complex.

We have used restriction enzyme digests, Southern blot analysis, and gene transfer experiments to identify a class I gene in the Q subregion of the murine major histocompatibility complex. By comparisons of class I genes from Q congeneic strains, five restriction fragment length polymorphisms were identified. Further studies of mutant (Qa-2-) and wild-type (Qa-2+) BALB/c sublines indicated that at least part of the structural or regulatory gene controlling a Q subregion antigen resides on a 3.7-kilobase Xba I DNA fragment and is absent in all tested Qa-2- strains. The spontaneously occurring Qa-2- BALB/cBy mutant appears to have an extensive deletion in this region. The identity of this gene was confirmed by gene transfer experiments as well as by the use of a single-copy probe.

Animals↗
PubMed1982

Supramolecular relationships of membrane antigens on the murine thymocyte.

The topographical relationships of Thy-1, Ly-1, Ly-2, and T200 were examined on the murine thymocyte. The inhibition of the binding of radiolabelled monoclonal antibody after incubation with unlabelled heterologous antibody was used as a measure of the proximity of the target antigens on the cell surface. On unfixed cells, prior incubation with anti-Thy-1.2 impeded the attachment of labelled anti-Ly-1, anti-Ly-2, and anti-T200. Anti-T200, but not anti-Ly-1, or anti-Ly-2, was capable of impeding the attachment of labelled anti-Thy-1.2 on unfixed cells. In general, gentle fixation with paraformaldehyde did not alter these inter-relationships. The possible functional contributions of such supramolecular relationships are discussed.

Animals↗
PubMed1982

Qa-1 and Qa-2 expression on CFU-s.

Multipotential stem cells can be detected in bone marrow cells preparations by injecting these cells into syngeneic irradiated hosts. Colonies (CFU-s) are visible macroscopically on the spleen after 8 days. Pretreatment of A-Tlab (Qa-1.2) bone marrow with A-anti-A-Tlab serum (anti-Qa-1.2), in the presence of complement, reduced CFU-s by 80% whereas A-Tlab anti-A serum (anti-Qa-1.1) treatment had no effect. Pretreatment of A(Qa-1.1) bone marrow with A-Tlab anti-A serum reduced macroscopic splenic colonies by 78%. Similar results were obtained by using C57BL/6 (Qa-1.2) and B6-Tlaa (Qa-1.1) bone marrow. Thus, both Qa-1.1 and Qa-1.2 are expressed on CFU-s. Qa-2 expression on CFU-2 was examined in the same manner. B6.KI anti-B6 (anti-Qa-2,3) serum reduced CFU-s numbers by 87% on B6 (Qa-2,3+) while having little or no effect on B6.KI (Qa-2,3-). Treatment with D3.262, a monoclonal anti-Qa-2 antibody, reduced B6 CFU-s by 80%, and had no effect on B6.KI CFU-s. Detection of Qa-1 and Qa-2 on CFU-s underscores the wide distribution of the Qa antigens in the hematopoietic system.

Animals↗
PubMed1978

A simple method for the preparation of antisera specific for murine immunoglobulin heavy chains.

Rabbit antisera were prepared against mouse immunoglobulin mu and gamma chains by immunizing rabbits with their own erythrocytes coated with murine anti-rabbit erythrocyte immunoglobulin. In the preparation of these antisera, we exploited the observation that the primary immune response in C57BL/10ScSn (B10) mice is almost exclusively IgM, while hyperimmune antiserum of A/WySn (A) is mostly IgG. After appropriate absorption with thymocytes and rabbit erythrocytes (Rrbc) coated with B10 or A antiRrbc Ig, the sera were shown to be specific by immunoelectrophoresis, indirect immunofluorescent staining, and complement-mediated cytotoxicity. This technique is simple, requires almost no equipment, and a large quantity of specific antiserum can be prepared quite economically.

Animals↗
PubMed1978

Antigen-induced murine B cell lymphomas. I. Induction and characterization of CH1 and CH2.

Two unusual murine lymphomas, designated CH1 and CH2, were produced in the newly developed double congenic strain of mice, B10 H-2a H-4b p/Wts. Both tumors lack the T cell-specific antigen (thy-1), but express cell surface immunoglobulin and the H-2K, H-2D, and Ia specificities determined by the H-2a haplotype. Further studies have demonstrated that these tumors represent "early" B cells in that they express surface IgM (mu heavy and lambda light chains), but do not bear surface delta, gamma, or alpha heavy chains. CH1 and CH2 lack surface C3 receptors and results from assays for Fc receptors have proven variable. A competition radioimmunoassay directed against the gp71 group-specific antigen of Friend leukemia virus has shown that there is a murine leukemia virus associated with these tumors, however, we have been unable to establish a causal relationship between the virus and this malignancy. A comparison of the surface characteristics of these tumors with other mammalian B cell lymphomas is presented.

Animals↗
PubMed1978

Antigen-induced murine B cell lymphomas. II. Exploitation of the surface idiotype as tumor specific antigen.

In the accompanying report, we have described the characterization of two unusual murine B cell lymphomas, CH1 and CH2. A heterologous antiserum, which we refer to as "anti-idiotype" serum, has been raised to the detergent-solubilized surface immunoglobulin of CH1. The following criteria have established that this antiserum is specific for the CH1 tumor and that it reacts with V region determinants of the tumor surface IgM: 1) the antiserum reacts with CH1 tumor cells, but not normal mouse lymphoid cells or CH2 tumor cells, in indirect immunofluorescence and C-dependent cytotoxicity testing, 2) capping with the anti-idiotype serum removes all or most of the tumor surface Ig, 3) the antiserum forms a single band of precipitation against serum from CH1 tumor-bearing mice, when tested by double diffusion precipitin analysis, and 4) a single band of precipitation is formed in the electrophoretic migration position of IgM when the anti-idiotype antiserum is tested against serum from CH1 tumor-bearing mice in immunoelectrophoresis. Furthermore, we have demonstrated that this antiserum is useful in monitoring tumor growth and is a potent immunotherapeutic agent. Specifically, 50% of mice injected with a lethal tumor inoculum and given a small dose of anti-idiotype serum 2 days later remain tumor free, whereas all tumor-challenged control mice died within 30 days.

Absorption↗
PubMed1975

Genetic variation of an intestinal leucine arylaminopeptidase (Lap-1) in the mouse and its location on chromosome 9.

Electrophoretic variation for an intestinal enzyme that cleaves L-leucyl-beta-naphthylamide has been discovered among inbred mouse strains. Several strains including related strains C57BL/6J, C57BL/10J, C57BR/cdJ, C57L/J, and C58/J demonstrate an electrophoretic band of this enzyme that is absent in other strains and stocks thus far observed. The enzyme is tentatively being called leucine arylaminopeptidase (LAP) and the variant genetic locus Lap-1. The presence of the band is determined by an allele designated Lap-1a. Homozygotes for the alternate allele, Lap-1b, are without the band and heterozygotes are, under our electrophoretic conditions, indistinguishable from Lap-1a homozygotes. Data from recombinant inbred lines and a B6D2F1 X DBA/2J backcross established linkage of Lap-1 to dilute (d) and supernatant malic enzyme (Mod-1) on chromosome 9 in the following order: Lap-1-d-Mod-1. The Lap-1 to d map distance was estimated to be 21.3 +/- 4.6 cM from backcross data and 8.1 +/- 4.8 cM from recombinant inbred lines.

Alleles↗
PubMedDate not supplied

Allogeneic reactivity in normal mouse serum.

Normal C57BL/6 (B6) mouse serum was tested in the direct cytotoxicity assay for specific reactivity against lipopolysaccharide (LPS)-stimulated mouse spleen cells. Selective reactivity was found in weanling and adult serum against lymphoblasts from mice that express an antigen encoded by the H-2Kk region of the major histocompatibility complex (MHC). Other strains, congenic with B6 at the MHC, did not exhibit the same alloreactivity. Serum from mice of a congenic strain being derived in our laboratory, which differs from B6 at two unlinked loci, Tla and nu, exhibited similar reactivity against the B6-H-2k LPS-stimulated lymphoblasts, implying that a competent T cell compartment is not necessary for generation of this reactivity. Such reactivities may result from environmental stimulation of the immune system, from internal immunoregulatory controls, or from some combination of these immune stimuli.

Animals↗