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

The major surface antigen (30 kDa) of Brugia pahangi has been characterised by a number of biochemical and immunochemical means. The 30 kDa polypeptide is a glycoprotein which can be extracted from the worm surface by homogenization in the absence of detergents. The 30 kDa polypeptide can be metabolically labelled with [35S]methionine in adult male and female parasites. In addition small amounts of the 35S-labelled 30 kDa antigen can be detected in the medium of worms cultured in vitro. 125I labelling of the excretory-secretory (ES) products of adult male and female parasites followed by immunoprecipitation and peptide mapping has confirmed the relationship between the surface located 30 kDa polypeptide and that released in vitro.
Mol Biochem Parasitol 1988 Jan 01
PMID:The biochemical and immunochemical characterisation of the 30 kilodalton surface antigen of Brugia pahangi. 334

The expression of myeloid-associated cell surface antigens detected by monoclonal antibodies (MoAb: MCS-2, MCS-1, MY7, MY9, Leu-M1, OKM1, VIM-D5, Mol, My-1, MY8, MY4, Leu-M3, VIM-D2, Mo2) of the HLA-DR/Ia-like antigen and of the Fc-receptor was determined on the blast cells from 91 patients with acute myeloid leukaemias classified as M1-M5 in the French-American-British (FAB) system. The surface antigen analysis revealed a highly heterogeneous reaction profile. Nevertheless, distinctive patterns of marker expression referring to morphologically defined subgroups were delineated. Several MoAb (especially MCS-2 and MY7 which were positive in most cases of the five FAB subgroups) appear to be useful for the recognition of myelomonocytic cells regardless of the commitment to either the granulocytic or monocytic cell lineage whereas other Mo Ab (especially MY4, Leu-M3, VIM-D2, Mo2) react predominantly with the monocytic variants and are helpful in the identification of monocytic commitment. The 91 cases could be divided into three immunologically defined phenotypes (Types I-III) corresponding to sequential differentiation levels. Correlations of these MoAb-defined phenotypes with the FAB subtyping showed that immunological and morphological classifications are not completely concordant and that only the parameters Type I and FAB M1 were significantly related. A scheme of early myeloid differentiation sequences based on the expression of surface antigens is presented.
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PMID:Correlation of surface marker expression with morphologically and immunologically defined subclasses of acute myeloid leukaemias. 346 28

Our previous work by immunoprecipitation with a specific monoclonal antibody showed multiple, closely apposed electrophoretic bands of a major surface antigen specific to the promastigote stage of Leishmania mexicana amazonensis. Here, we analyzed the antigen during growth and transformation of this parasite with particular emphasis on the origin of the multiple bands. Immunobinding assays revealed the presence of the antigen throughout all phases of growth of cloned and uncloned promastigotes in various media for different number of generations. More antigen is expressed by promastigotes grown in Medium 199 plus fetal bovine serum than those in serum-supplemented Schneider's medium or a defined medium; however, this is clone-dependent. Purified monoclonal antibody coupled to Affi-Gel 10 gave a high capacity of antigen binding, resolving four electrophoretic bands of 60-66 kDa. A 63 kDa membrane protein, representing one of the four bands, became predominant after [35S]methionine label and chase. Pretreatment of promastigotes with 10 micrograms ml-1 tunicamycin reduces the antigen to a single band of 54 kDa. Treatment of the antigen bound to the affinity gel with endoglycosidase-H produces similar, but less complete effect. These results indicate glycosylation of this antigen with asparagine-linked oligosaccharides, which appears to account at least in part for its expression as multiple, closely apposed bands during biosynthesis. Binding of fluorescein isothiocyanate-labeled 6H12 monoclonal IgG or Fab to the promastigotes showed an even distribution of the antigen over the cell surface and its capping upon the addition of rabbit anti-mouse IgG. Additional hybridomas prepared against amastigotes yielded monoclonal antibodies which recognized surface antigens common to both stages of the parasite.
Mol Biochem Parasitol 1986 Feb
PMID:Expression and size heterogeneity of a 63 kilodalton membrane glycoprotein during growth and transformation of Leishmania mexicana amazonensis. 351 77

Two polypeptides of 150 and 130 kDa present in all asexual and sexual blood stages of Plasmodium falciparum have been identified with anti-gametocyte monoclonal antibodies. The apparent molecular mass of these antigens is identical in different developmental stages of the parasite and in different isolates. These antigens are released in the culture supernatant during the process of schizogony and are also detected in the sera of patients undergoing a primary P. falciparum infection. Antibodies against these antigens occur in sera of a large percentage of children and most adults living in malaria-endemic areas, suggesting that they are highly immunogenic. The anti-gametocyte monoclonal antibodies react with a synthetic peptide (Glu-Glu-Asn-Val)4, present in antigen Pf155 [Perlmann, H. et al. (1984) J. Exp. Med. 159, 1686-1704] and in the ring-infected erythrocyte surface antigen [Coppel, R.L. et al. (1984) Nature 310, 789-792], indicating that these polypeptides are closely related. In contrast, two glycophorin-binding proteins of similar molecular mass [Perkins, M.E. (1984) J. Exp. Med. 160, 788-798] appear to be entirely distinct from the presently described antigens. We failed to observe any in vitro inhibitory activity of the monoclonal antibodies on merozoite invasion and on gametocyte infectivity.
Mol Biochem Parasitol 1986 Jun
PMID:Monoclonal anti-gametocyte antibodies identify an antigen present in all blood stages of Plasmodium falciparum. 352 45

The structures of the major merozoite surface antigen of Plasmodium falciparum and the gene encoding it were indistinguishable for the Wellcome strain and the Thai clone T9/94 but different for clones T9/96, T9/98, and T9/101. The central portion of the gene is subject to the greatest variation in structure. The protein from all five lines was found to be posttranslationally modified by covalent addition of both carbohydrate and fatty acid.
Mol Cell Biol 1986 Mar
PMID:Structural diversity of the major surface antigen of Plasmodium falciparum merozoites. 353 52

To investigate the mechanism by which complex membrane proteins achieve their correct transmembrane orientation, we examined in detail the hepatitis B surface antigen for sequences which determine its membrane topology. The results demonstrated the presence of at least two kinds of topogenic elements: an N-terminal uncleaved signal sequence and an internal element containing both signal and stop-transfer function. Fusion of reporter groups to either end of the protein suggested that both termini are translocated across the membrane bilayer. We propose that this topology is generated by the conjoint action of both elements and involves a specifically oriented membrane insertion event mediated by the internal sequence. The functional properties of each element can be instructively compared with those of simpler membrane proteins and may provide insight into the generation of other complex protein topologies.
Mol Cell Biol 1987 Oct
PMID:Multiple topogenic sequences determine the transmembrane orientation of the hepatitis B surface antigen. 368 95

Antibody responses to the three envelope (env) proteins of hepatitis B viral particles (HB-VP): the S-encoded P25 polypeptide; the pre-S(2)- and S-encoded GP33/GP36 polypeptide; and the large entire env gene (pre-S + S) product, P39/GP42, were investigated using a Western immunoblotting assay (WIBA). HB-VP proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and transferred to nitrocellulose by electroblotting were used as antigenic probes to determine the polypeptide specificity of these antibodies present in immune individuals. Antisera from human subjects either after a natural HBV infection or after active immunization with the hepatitis B vaccine licensed in France were selected on the basis of a positive serological RIA test for antibodies against hepatitis B surface antigen (HBsAg). In all studied cases, the lack of reactivity of the anti-HBs/P25 antibodies in blots from reduced SDS gels confirms that the S-related-determinants have a conformation sensitive to denaturing agents. In contrast, the anti-pre-S(2)/GP33-GP36 antibodies and the anti-pre-S(1)/P39-GP42 antibodies can be easily detected in WIBA, providing these antibodies recognize the disulfide-bond independent pre-S determinants on the denatured env proteins. However, antisera raised in guinea-pigs against individual HBsAg polypeptides contain antibodies reacting with denatured S-proteins, suggesting that the sequential S-determinants are lost during HBV morphogenesis. Antibody responses in HBV convalescing patients or vaccinated healthy donors are shown to be characterized by: an early transient polypeptide specific-antibody response to pre-S(2)-sequences (detected in WIBA); a persistent antibody response to conformation-dependent S-determinants (detected in RIA). This implies that effective long-term protection against HBV infection requires antibodies directed to native env proteins.
Mol Immunol 1986 May
PMID:Immunochemical structure of the hepatitis B surface antigen vaccine--II. Analysis of antibody responses in human sera against the envelope proteins. 374 12

cDNA clone banks have been constructed in a plasmid vector (pJSC73) using mRNA isolated from adult worms and eggs of Schistosoma mansoni. These clone banks have been screened by message selection (hybrid release translation) and clones containing fragments of genes encoding schistosome antigens have been identified by immunoprecipitation of the corresponding mRNA in vitro translation product. Over 50 clones encoding schistosome antigens have been identified including those of the 100 000, 86 000, 28 000, and 27 000 molecular weight surface antigen precursors.
Mol Biochem Parasitol 1986 Jan
PMID:Identification by message selection of cDNA clones encoding antigens of Schistosoma mansoni. 375 8

The expression of differentiation-associated surface antigens by the clonogenic leukemic cells from 20 patients with acute myeloblastic leukemia (AML) was studied with a panel of seven cytotoxic monoclonal antibodies (anti-Ia, -MY9, -PM-81, -AML-2-23, -Mol, -Mo2, and -MY3). The surface antigen phenotypes of the clonogenic cells were compared with the phenotypes of the whole leukemic cell population, and with the phenotypes of normal hematopoietic progenitor cells. In each case the clonogenic leukemic cells were found within a distinct subpopulation that was less "differentiated" than the total cell population. Clonogenic leukemic cells from different patients could be divided into three phenotype groups. In the first group (7 of 20 cases), the clonogenic cells expressed surface antigens characteristic of the normal multipotent colony-forming cell (Ia, MY9). These cases tended to have "undifferentiated" (FAB M1) morphology, and the total cell population generally lacked expression of "late" monocyte antigens such as MY3 and Mo2. A second group (seven cases) of clonogenic cells expressed surface antigens characteristic of an "early" (day 14) colony-forming unit granulocyte-monocyte (CFU-GM), and a third group (six cases) was characteristic of a "late" (day 7) CFU-GM. The cases in these latter two groups tended to have myelomonocytic (FAB M4) morphology and to express monocyte surface antigens. These results suggest that the clonogenic cells are a distinct subpopulation in all cases of AML, and may be derived from normal hematopoietic progenitor cells at multiple points in the differentiation pathway. The results further support the possibility that selected monoclonal antibodies have the potential to purge leukemic clonogenic cells from bone marrow in some AML patients without eliminating critical normal progenitor cells.
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PMID:Heterogeneity of clonogenic cells in acute myeloblastic leukemia. 385 66

A temperature shift from 40 to 28 degrees C rapidly induced expression of a specific immobilization antigen at the cell surface in Tetrahymena thermophila. This transformation was inhibited by actinomycin D and cycloheximide but not by colchicine or cytochalasin B. The major surface antigen expressed at 28 degrees C in cells homozygous for the SerH3 allele was partially purified, and an antiserum against this preparation was raised in rabbits. Electrophoresis, immunoblot, and [35S]methionine incorporation studies are reported which support the conclusion that the H3 antigen is an acidic protein with an Mr of approximately 52,000 daltons. An induced synthesis of the H3 immobilization antigen was detected within 30 min after a shift from 40 to 28 degrees C. This protein appeared to be synthesized in the microsomal fraction and transferred without cleavage to the cell surface, where it was inserted first into nonciliated regions.
Mol Cell Biol 1985 Aug
PMID:Expression of a cell surface immobilization antigen during serotype transformation in Tetrahymena thermophila. 391 84


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