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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Changes in the antigenicity of major histocompatibility complex (MHC) class I molecules resulting from the association of bovine beta 2-microglobulin (beta 2-m) with mouse class I heavy chains were investigated. Mice (H-2b) were immunized with syngeneic Concanavalin A (Con A) blasts induced in the presence of fetal calf serum (FCS) in conditions allowing exchange between mouse and bovine beta 2-microglobulin (beta 2-m). Spleen cells from hyperimmunized mice were fused with myeloma cells and two monoclonal antibodies which required for their reactivity the presence of FCS have been further studied. One of them (CAB 297) recognized a determinant of bovine beta 2-m which is present on free molecules in solution as well as when they are associated with either mouse or bovine class I heavy chains. In contrast, the second monoclonal antibody (CBB 70) did not react with free bovine beta 2-m molecules, nor with beta 2-m associated with bovine class I heavy chains. It did react with cells of some H-2 haplotypes (b, f, p and r) but only when their class I heavy chains are associated with bovine or with human beta 2-m. Therefore, expression of the CBB 70 defined antigenic determinant requires both xenogeneic beta 2-m and class I heavy chain of a given H-2 molecule. In order to precisely localize the antigenic determinant defined by this monoclonal antibody and therefore the region altered by the association of class I heavy chain with xenogeneic beta 2-m, we made use of exon shuffled class I molecules. The results indicate that changes induced by the association of bovine beta 2-m with H-2 class I heavy chain affect the conformation of the alpha 2 domain. These studies illustrate that MHC class I molecules exhibit a considerable conformational flexibility which could influence their ability to bind and present various peptides to the T-cell receptor.
Mol Immunol 1992 Apr
PMID:Localization of the conformational alteration of MHC molecules induced by the association of mouse class I heavy chain with a xenogeneic beta 2-microglobulin. 137 66

The effect of interleukin 3 (IL-3) on lymphokine-activated killer cell (LAK) generation in splenic lymphocytes was examined in patients with gastric cancer or idiopathic thrombocytopenic purpura (ITP). IL-3 alone did not induce any significant LAK activity from splenic lymphocytes. However, IL-3 addition to the culture with low-dose IL-2 significantly augmented the activity of LAK cells. Spleen cells precultured with IL-3 for 2 days and then added to IL-2 became more potent LAK cells than the spleen cells cultured with the same doses of IL-3 plus IL-2. Phenotypic analysis using flow cytometry demonstrated that IL-2 alone increased in cells expressing CD2+, -11+, and -16+ cells, whereas IL-3 plus IL-2 induced the expansion of CD3+ and CD8+ cells in addition to CD2+, -11+, and -16+ cells. These results suggest that IL-3 plus IL-2 phenotypically induces not only natural killer-like LAK cells (CD2+, -11+, and -16+) but T cell-like LAK cells (CD3+ and -8+). We are now investigating the characteristics of immature T cell populations in the spleen responsive to IL-3 using T-cell receptor antibody.
Mol Biother 1992 Jun
PMID:Augmentation of human lymphokine-activated killer cell activity in splenic lymphocytes by the combination of low-dose interleukin 2 plus interleukin 3. 151 99

A recombinant vaccinia virus was constructed which expressed the circumsporozoite protein of Plasmodium berghei. Four different strains of mice belonging to different haplotypes were immunized with the recombinant virus. The antibody response to the circumsporozoite protein as well as to vaccinia virus varied among the strains, independently of each other. The anti-circumsporozoite protein titers were comparable to that obtained on immunization with irradiated sporozoites. Spleen cells from H2d mice immunized with P. berghei sporozoites showed a significant proliferative response when cultured in vitro with a low multiplicity of the recombinant vaccinia virus. A weak cytotoxic T lymphocyte response specifically targeting the circumsporozoite protein could be identified in spleens of BALB/c (H2d) mice immunized with vaccinia virus when BALB 3T3 cells transformed with a plasmid expressing the circumsporozoite protein under control of the simian virus 40 promoter were used as target cells in the cytotoxic T lymphocyte assay. However, none of the recombinant virus-immunized animals could be protected from a challenge of sporozoites even at the lowest dose of parasite used.
Mol Biochem Parasitol 1991 Sep
PMID:Studies using a recombinant vaccinia virus expressing the circumsporozoite protein of Plasmodium berghei. 177 92

We have developed a limiting dilution clonal assay for determining the frequency of 6-thioguanine-resistant (TGr) lymphocytes produced in rats by in vivo exposure to genotoxic agents. Spleen lymphocytes were isolated from female Fischer 344 rats and were cultured with 1 microgram/ml of phytohemagglutinin (PHA) for 40 hr. Northern blot analysis revealed that this procedure resulted in increased hprt and beta-actin mRNA synthesis. Conditions for optimum cloning were established by culturing four PHA-primed lymphocytes/well in 96-well round-bottom microtiter plates containing a medium supplemented with interleukin-2. These cultures also contained autologous and/or TK6 feeder cells inactivated with different doses of irradiation. Lymphocyte cloning efficiencies (CEs) were highest in plates containing both irradiated TK6 cells (5 x 10(3) cells/well; 90 Gy) and irradiated autologous feeder cells (5 x 10(4) cells/well; 50 Gy). CE did not depend on the number of primed lymphocytes/well when four or fewer target cells/well were cloned. To measure the effects of chemical mutagens on the frequency of TGr lymphocytes, rats were given a single i.p. injection of 0-150 mg/kg of N-ethyl-N-nitrosourea (ENU), a direct-acting alkylating agent, or 0-50 mg/kg of cyclophosphamide (CP), an indirect acting alkylating agent. Lymphocytes were isolated, primed, and cloned at 4 weeks after CP treatment and at 1, 2, 4 and 6 weeks after ENU treatment. CE in these cultures ranged from 12% to 27%. Cultures were also established for measuring CE in the presence of 6-thioguanine (TG) and these contained 5 x 10(3) irradiated TK6 cells and 5 x 10(4) primed rat lymphocytes/well. The frequency of TGr lymphocytes was calculated by correcting the CE in the presence of TG with the CE measured in its absence. ENU exposure produced a higher frequency of TGr lymphocytes than CP, but both chemicals produced a dose-dependent increase in TGr cells. In addition, the frequency of ENU-induced TGr lymphocytes increased with time after treatment. The TGr cells are presumed to be hprt mutants, but further analysis at the DNA level is required to establish this. The dose-dependent responses obtained with both ENU and CP treatments suggest that rat lymphocytes are sensitive to direct- and indirect-acting alkylating agents administered in vivo and that the rat lymphocyte assay is a useful complement to the in vivo/in vitro mouse assay for determining the mutagenicity of environmental toxicants.
Environ Mol Mutagen 1991
PMID:Induction of 6-thioguanine-resistant lymphocytes in Fischer 344 rats following in vivo exposure to N-ethyl-N-nitrosourea and cyclophosphamide. 202 92

Murine monoclonal antibodies against human/rat corticotrophin-releasing factor-41 (CRF-41) were produced and characterized for use in the immunological and biological characterization of CRF-41. Spleen cells from BALB/c mice immunized with CRF-41 conjugated to bovine gamma-globulin were fused with a BALB/c-derived non-secretor X-63 myeloma line. Hybridomas were selected for CRF antibody production by enzyme-linked immunosorbent assay, and positive hybridomas cloned twice. Three monoclonal antibodies were obtained (KCHMB001, KCHMB002 and KCHMB003) and characterized as IgG1, IgG1 and IgG2a isotypes respectively, with affinity constants for rat CRF-41 of 30, 53 and 34 nmol/l respectively. All three monoclonal antibodies recognize an epitope contained between residues 34 and 41 of the human/rat sequence. The antibodies were able to neutralize the ACTH-releasing activity of rat CRF-41, applied to rat pituitary fragments in vitro, in a dose-dependent manner. Isoelectric focusing showed that KCHMB003 detected bands of synthetic rat CRF-41 and rat [Met(O)21,38]-CRF-41 at pH 7.1 and 6.8 respectively. Use of KCHMB003 in a two-site enzyme-amplified immunoassay showed that this antibody recognizes both synthetic rat CRF-41 and immunoreactive CRF-41 in rat hypothalamic tissue extracts.
J Mol Endocrinol 1990 Oct
PMID:Production and utilization of monoclonal antibodies to human/rat corticotrophin-releasing factor-41. 224 88

Thirteen monoclonal antibodies (MAbs) were produced against Lol p I (Rye I), the major Lolium perenne (rye grass) pollen allergen. Spleen cells from A/J and SJL mice immunized with highly purified Lol p I (Lol I) were allowed to fuse with cells from the non-secreting Sp2/0-Ag14 myeloma cell line. Each MAb was analyzed for antigenic specificity by radioimmunoassay (RIA) using 125I-Lol I. The epitope specificities of seven of the MAbs were examined by competitive binding against a labelled standard MAb for the Lol I antigen (Ag). The dissociation constant, Kd, of one MAb (No. 3.2) that was studied most extensively was determined by double Ab RIA to be 3.5 X 10(-6) L/M. This MAb recognized the related 27,000-30,000 Group I glycoproteins found in the pollens of nine other species of grass pollens tested, including weak binding to Bermuda grass Group I (Cyn d I), which by conventional analysis using polyclonal anti-Lol I serum shows no detectable binding. Monoclonal antibody No. 3.2 was coupled covalently to Sepharose 4B and used to prepare highly purified Lol I from a partially purified rye pollen extract. Finally, an RIA was developed which permitted the analysis of the Group I components in rye grass and nine other grass pollen species. The latter assay is likely to prove useful in the standardization of grass pollen extracts according to their Group I contents.
Mol Immunol 1986 Dec
PMID:Monoclonal antibodies to the major Lolium perenne (rye grass) pollen allergen Lol p I (Rye I). 243 41

Two anti-TNP antibodies exhibiting unusual features are described. They were obtained in two independent fusions. Spleen cells from CB20 mice sensitized with TNP-Ficoll and challenged with TNP-LPS were fused with SP2/0 myeloma cells. One of these hybridomas, CBT3, secretes antibodies which react with both monospecific anti-gamma 2b and anti-gamma 3 anti-isotypic sera; the second hybridoma, CBT4, secretes antibodies reacting with monospecific anti-mu and anti-gamma 2b sera. Only one type of immunoglobulin is secreted by each hybridoma, ruling out the hypothesis of hybrid molecules formed by distinct heavy chains. These results imply that the two heavy chains are made up from elements encoded by gamma 3 and gamma 2b genes in CBT3 and by gamma 2b and mu genes in CBT4. The molecular mechanisms underlying the production of these singular heavy chains are discussed.
Mol Immunol 1987 Jan
PMID:Hybrid polypeptide heavy chains produced by two hybridoma lines. 244 Dec 46

Anti-mu treated mice have been used extensively as a model for suppressed B-cell development [Murgita R. A., Mattioli C. A. and Tomasi T. B., Jr. (1973) J. exp. Med. 138, 209; Manning D. D. (1975) J. Reticuloendothel. Soc. 18, 63; Manning D. D. and Jutila J. W. (1972) J. Immun. 108, 282; Janeway C. A., Jr., Murgita R. A., Weinbaum F. I., Asofsky R. and Wigzell H. (1977) Proc. natn. Acad. Sci. U.S.A. 74, 4582; Hayglass K. T., Naides S. J., Benacerraf B. and Sy M.-S. (1985) J. Molec. Cell. Immun. 2, 107; Manning D. D. (1972) J. Immun. 109, 1152; Cooper M. D., Kearney J. F., Gathings W. E. and Lawton A. R. (1980) Immun. Rev. 52, 29; Burrows P. D., Kearney J. F., Lawton A. R. and Cooper M. D. (1978) J. Immun. 120, 1526]. However, little molecular evaluation has been performed on these animals to determine the level at which B-lineage cells are arrested. Experiments reported here were designed to determine the effects of anti-mu treatment of newborn mice on Ig-specific mRNA expression in lymphocyte populations. Newborn CBA/J mice received i.p. injections of goat anti-mu IgG or non-immune goat IgG, every 2 days, from birth until age 4 weeks. The degree of B-cell suppression in anti-mu treated mice was evident by low serum Ig levels and lack of surface Ig+ cells in splenic lymphocytes. Morphologically, spleens of B-cell depleted mice were slightly reduced or normal size, while the total area of Peyer's patches (PP) was three-fold less than control mice. Spleen cells from anti-mu suppressed mice contained high levels of mu-mRNA, but markedly reduced levels of mRNA specific for other Ig heavy-chain isotypes, as determined by DNA excess dot blot and Northern blot hybridizations. RNA specific for other sequences (actin or IL-2 receptor) was not affected and hybridization to parent plasmid (pACYC) was not detected. In addition, suppression of kappa- and lambda-mRNA accumulation was evident. This was surprising, since the target for anti-mu treatment appears to be a B-cell population expressing intact surface IgM, a stage in B-cell development in which both mu- and light-chain-specific mRNA accumulation should be detected. Our results suggest one of the following models: (1) anti-mu treatment deletes all Ig+ cells from the animal, so that only mu expressing pre-B-cells remain; or (2) anti-mu suppresses B-cell development by inhibiting kappa and lambda transcription, perhaps by some feedback mechanism in which the presence of surface Ig is required to maintain light-chain transcription.
Mol Immunol 1989 Apr
PMID:Anti-mu treatment suppresses immunoglobulin light-chain gene expression and Peyer's patch development. 249 38

Lymphocytes of autoimmune mice have been reported to have defective IL-2 production and proliferation in response to the mitogen concanavalin A. We have examined transcription of lymphokine genes in Con A stimulated spleen cells from both autoimmune and normal mice and found that IL-2, IL-4 and gamma-interferon (IFN gamma) were induced in all mice tested. Spleen cells were taken from young (pre-disease) or old (clinically active) MRL/lpr (lpr) and male BXSB autoimmune mice and from their normal counterparts (MRL/n, BXSB females, BALB/c and DBA/2) and stimulated with Con A. Con A induced production of IL-2, IL-4 and IFN gamma message and protein, and kinetics of induction did not vary significantly among the strains. However, in old lpr mice, levels of IL-2 protein and mRNA were about 10-fold lower than in other strains; IL-4 protein and mRNA were decreased approximately three-fold; and IFN gamma mRNA was readily detected in unstimulated cells and low but detectable levels of protein were produced constitutively. In contrast, little or no defect in IL-2 or IL-4 transcription or secretion were seen in male BXSB mice and no constitutive IFN gamma transcription was seen in this strain. These data indicate that all three lymphokine genes are activated by Con A in autoimmune mice, even though Con A-induced proliferation is defective in these mice. Furthermore, autoimmune mouse strains vary in terms of lymphokine expression: male BXSB mice display a normal lymphokine profile, whereas lpr mice show a marked imbalance of lymphokines compared to normal controls.
Mol Immunol 1989 Jul
PMID:Expression of lymphokine genes in splenic lymphocytes of autoimmune mice. 250 45

Retroviral vectors were used to introduce an activated ras gene into murine pluripotent hemopoietic stem cells. We attempted to reconstitute the hemopoietic system of lethally irradiated mice with isolated spleen colonies obtained in vivo after injection of infected bone marrow cells. Spleen colonies derived from infected bone marrow were inefficient in promoting long-term survival of irradiated hosts. This loss of reconstitutive capacity of spleen colonies was not due to the retroviral infection per se but to the in vitro culture of spleen colony precursors. Incubation for 24 h in the presence of fetal calf serum and interleukin-3 without virus-producing cells was sufficient to abolish completely the reconstitutive capacity of spleen colonies while maintaining both self-renewal and pluripotential capacities of spleen colony precursors. These results show that the in vitro manipulation of stem cells that is included in current protocols for retroviral infection can modify the developmental potential of these cells. This finding clearly indicates that the use of retroviral vectors can introduce a bias in the analysis of hemopoiesis.
Mol Cell Biol 1989 Oct
PMID:Mock retroviral infection alters the developmental potential of murine bone marrow stem cells. 257 33


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