Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0393754 (HSA)
 2,996 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several investigators have shown that the expression of the sialyl-Tn (STn) epitope on cancer associated mucins is associated with a poor prognosis in several human cancers suggesting that STn may have functional significance in metastasis. We postulate that antibodies against the STn-epitope can inhibit metastasis. We generated a synthetic "mimic", NANA alpha (2-->6)GalNAc alpha-O-Crotyl (STn-crotyl), of the natural O-linked epitope on mucins, NANA alpha (2-->6)GalNAc alpha-O-Serine (STn-serine). STn-crotyl was conjugated to the carrier protein KLH through the crotyl linker arm and a "vaccine" containing STn-KLH plus Detox adjuvant was formulated. The immunogenicity of the vaccine was evaluated in BALB/c mice and in metastatic breast cancer patients. The specificity and titres of IgG antibodies were evaluated by ELISA on ovine submaxillary mucin (OSM) solid phases. OSM is a convenient source of repeating, natural O-linked STn-serine structures. Mice immunized three times with as little as 0.25 microgram of STn-KLH produced a median IgG titre of over 1:5000 on solid phase OSM. Anti-OSM IgG monoclonal antibodies generated from these mice were completely inhibited in their binding to solid phase OSM equally well by STn-serine and STn-crotyl synthetic haptens but not by several other closely related synthetic haptens. Breast cancer patients immunized 2-8 times with 25 or 100 micrograms of the same vaccine produced median peak IgG titres 1:1280 measured on STn-HSA and 1:80 on OSM. Once again, hapten inhibition experiments with the human sera demonstrated the specificities of the IgG antibodies for STn-crotyl and STn-serine, but not against several other related synthetic haptens. We found little or no evidence that the artificial linker arm (crotyl linker) contributed significantly to either the titre or affinity of the antibodies generated in either mice or human breast cancer patients. This suggests that the antibodies recognized the cancer-associated disaccharide NANA alpha (2-->6)GalNAc. Evidence of a clinical response was noted in several of the immunized breast cancer patients with other patients showing prolonged disease stability.
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PMID:Specificity of the IgG response in mice and human breast cancer patients following immunization against synthetic sialyl-Tn, an epitope with possible functional significance in metastasis. 752 78

We generated a synthetic epitope, NANA alpha(2-6) GalNAc alpha-O-Crotyl (STn-crotyl), designed to "mimic" the natural O-linked epitope expressed on human carcinoma cells, NANA alpha(2-6)GalNAc alpha-O-Serine (STn-serine). STn-crotyl was conjugated to the carrier protein KLH through the crotyl linker arm, and a "vaccine" containing STn-KLH plus DETOX adjuvant was formulated. The immunogenicity of the vaccine was evaluated preclinically in CAF1 mice and subsequently in patients with metastatic breast cancer. The specificity and titers of IgG antibodies were evaluated by kinetic ELISA on synthetic STn-HSA and on ovine submaxillary mucin (OSM) solid phases. Ovine submaxillary mucin is a convenient source of repeating, natural O-linked STn-serine structures. Mice immunized three times with as little as 0.25 micrograms of STn-KLH produced IgG titers ranging from 1:10(4) to 1:10(5) when tested on solid phase OSM. Anti-OSM IgG, both polyclonal and monoclonal antibodies, generated from these mice were completely inhibited in their binding to solid phase OSM equally well by STn-serine and STn-crotyl synthetic haptens but not by several other closely related synthetic haptens. These monoclonal antibodies also bound to STn determinants on human tumor cell surfaces. Breast cancer patients immunized with 100 micrograms of the same vaccine produced median peak IgG titers 1:1280 measured on STn-HSA and 1:160 on OSM. Hapten inhibition experiments with the human sera demonstrated the specificities of the IgG antibodies for STn-crotyl and STn-serine, but not against several other related synthetic haptens. We found little evidence that the artificial linker arm (crotyl linker) contributed substantially to either the titer or affinity of the antibodies generated in either mice or human breast cancer patients. This suggests that the antibodies recognized the cancer-associated disaccharide NANA alpha(2-->6)-GalNAc. Small but not large doses of STn-KLH immunogen induced anti-STn DTH responses in mice that were inversely proportional to the antibody responses. Evidence of a clinical response was noted in some of the immunized breast cancer patients, with other patients showing prolonged disease stability.
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PMID:Immune responses of mice and human breast cancer patients following immunization with synthetic sialyl-Tn conjugated to KLH plus detox adjuvant. 769 Feb 15

The humoral immune response of 85 metastatic breast, ovarian, and colorectal cancer patients was analyzed after immunization with THERATOPE STn-KLH (KLH, keyhole limpet hemocyanin) cancer vaccine emulsified in DETOX adjuvant. Enzyme-linked immunosorbent assay (ELISA) antibody titers against the synthetic sialyl-Tn (STn) epitope were estimated by using solid phase STn-HSA and compared with antibody titers generated to the more biologically relevant natural mucin STn epitopes by using ovine submaxillary mucin (OSM) as a solid phase. Anti-KLH antibody titers were compared with anti-STn antibody titers as a specificity control. All but two patients generated increased anti-OSM antibody titers after immunization with STn-KLH. Breast and colorectal cancer patients who had the highest anti-OSM antibody titers, determined 4 weeks after the fourth immunization with STn-KLH (post-4 ASI), survived longer than the patients who had lower post-4 active specific immunotherapy (ASI) anti-OSM antibody titers. In contrast, there was no correlation of anti-KLH antibody titers with survival, demonstrating the specificity of the association of anti-OSM antibodies with survival. Cox multivariate survival analysis models were used to attempt to determine whether the induction of high-titer antibodies after immunization is a prognostic indicator independent of age, level of various tumor markers, extent of disease, lactate dehydrogenase (LDH) level, and route of administration of low-dose cyclophosphamide before ASI. Increased pre-ASI CA-125 serum levels in the ovarian cancer patients were predictors of poor survival, independent of all of the other prognostic factors. The postimmunization increase in anti-OSM immunoglobulin M (IgM) titer was independently associated with longer survival of the colorectal cancer patients. Increased anti-OSM IgG titers were associated with a marked increased survival of the breast cancer patients, which was independent of all other prognostic factors except the size of measurable metastatic lesions at trial entry and the route of administration of cyclophosphamide. In a randomized trial design, breast cancer patients who received low-dose intravenous cyclophosphamide just before ASI showed longer survival and generated higher anti-OSM antibody titers than did patients who received low-dose oral cyclophosphamide before ASI.
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PMID:Antibodies against mucin-associated sialyl-Tn epitopes correlate with survival of metastatic adenocarcinoma patients undergoing active specific immunotherapy with synthetic STn vaccine. 885 25

T, Tn, and sialyated Tn (sTn) are pancarcinoma antigens, and increased expression of these carbohydrate epitopes has been correlated with a poor prognosis in several epithelial malignancies. Ten murine monoclonal antibodies have been generated to these antigens, and compared by ELISA and immunohistochemistry to established mAbs reactive with these antigens. Nine mAbs (3 IgM and 6 IgG) reactive with synthetic T-human serum albumin (T-HSA) were produced after immunizing BALB/c mice with a synthetic T-keyhole limpet hemocyanin glycoconjugate (T-KLH). An additional IgM mAb (145.22) was produced in mice immunized with erythrocytes isolated from a patient with Tn syndrome. Three IgM and six IgG1 mAbs reactive with T-HSA did not react with natural T antigen present on desialyated glycophorin. All three IgM and several IgG1 mAbs, however, did react with LS-174T, a mucinous colon carcinoma cell line, 647V, a human bladder carcinoma cell line, and TA3Ha, a murine mammary carcinoma cell line as well as fresh frozen colon carcinomas. MAb 145.22 reacted with both natural and synthetic sources of sTn and Tn, as well as with LS-174T cells and mucin deposits in 10/11 colon carcinomas on fresh-frozen sections. MAb B72.3 reacted strongly with ovine submaxillary mucin (OSM) and sTn-HSA, while mAb CC49, a second-generation mAb to TAG-72 carcinoma mucin, reacted strongly with OSM, less strongly with desialyated OSM, and only weakly with sTn-HSA, suggesting that the epitope specificity for mAb CC49 is distinct from that of B72.3.
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PMID:Specificity analysis of murine monoclonal antibodies reactive with Tn, sialylated Tn, T, and monosialylated (2-->6) T antigens. 898 50

Terminal sialic acids on cell surface glycoconjugates can carry 9-O-acetyl esters. For technical reasons, it has previously been difficult to determine their precise distribution on different cell types. Using a recombinant soluble form of the Influenza C virus hemagglutinin-esterase as a probe for 9-O-acetylated sialic acids, we demonstrate here their preferential expression on the CD4 T cell lineage in normal B10.A mouse lymphoid organs. Of total thymocytes, 8-10% carry 9-O-acetylation; the great majority of these are the more mature PNA-, HSA-, and TCRhi medullary cells. While low levels of 9-O-acetylation are seen on some CD4/CD8 double positive (DP) and CD8 single positive (SP) cells, high levels are present primarily on 80- 85% of CD4 SP cells. Correlation with CD4 and CD8 levels suggests that 9-O-acetylation appears as an early differentiation marker as cells mature from the DP to the CD4 SP phenotype. This high degree of 9-O-acetylation is also present on 90-95% of peripheral spleen and lymph node CD4 T cells. In contrast, only a small minority of CD8 T cells and B cells show such levels of 9-O-acetylation. Among mature peripheral CD4 T lymphocytes, the highly O-acetylated cells are Mel 14(hi), CD44(lo), and CD45R(exon B)hi, features typical of naive cells. Digestions with trypsin and O-sialoglycoprotease (OSGPase) and ELISA studies of lipid extracts indicate that the 9-O-acetylated sialic acids on peripheral CD4 T cells are predominantly on O-linked mucintype glycoproteins and to a lesser degree, on sialylated glycolipids (gangliosides). In contrast, sialic acids on mucin type molecules of CD8 T cells are not O-acetylated; instead these molecules mask the recognition of O-acetylated gangliosides that seem to be present at similar levels as on CD4 cells. The 9-O-acetylated gangliosides on mouse T cells are not bound by CD60 antibodies, which recognize O-acetylated gangliosides in human T cells. Tethering 9-O-acetylated mucins with the Influenza C probe with or without secondary cross-linking did not cause activation of CD4 T cells. However, activation by other stimuli including TCR ligation is associated with a substantial decrease in surface 9-O-acetylation, primarily in the mucin glycoprotein component. Thus, 9-O-acetylation of sialic acids on cell surface mucins is a novel marker on CD4 T cells that appears on maturation and is modulated downwards upon activation.
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PMID:9-O-Acetylation of sialomucins: a novel marker of murine CD4 T cells that is regulated during maturation and activation. 916 29

Human biliary mucin and calcium binding protein (CBP) influence formation of both calcium salt precipitates and cholesterol crystals and colocalize in the center of cholesterol gallstones. We investigated how physiological concentrations of these proteins regulate cholesterol crystallization in model biles, supersaturated with cholesterol and calcium salts, mimicking pathological human bile. Using polarizing light microscopy and nephelometry to assess cholesterol crystallization, the influence of calcium ions and calcium phosphate precipitates in the absence and presence of mucin, CBP, and human serum albumin was determined. Calcium phosphate precipitates stimulated cholesterol crystallization more strongly than soluble calcium. Mucin also stimulated, and with soluble calcium or calcium phosphate precipitates additively increased, the cholesterol crystal mass. In the absence of mucin, only human serum albumin plus CBP, not these proteins individually, decreased the stimulating effect of calcium phosphate precipitates but not of soluble calcium. However, seeding of calcium phosphate precipitates in biles with mucins resulted in near complete cholesterol crystallization within one day whether CBP and HSA were or were not also present. In conclusion, calcium salt precipitates plus human biliary mucins induce rapid and complete crystallization of cholesterol from model biles, little influenced by human biliary calcium binding proteins.
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PMID:Mucins and calcium phosphate precipitates additively stimulate cholesterol crystallization. 974 86

Non-immobilised ligand interaction assay (NILIA) by CD spectroscopy provides an excellent technique to study molecular interactions in solution. Here are discussed molecular interactions of several systems that involve hosts and ligands with wide range of molecular sizes. Cytokine rhGM-CSF (14.6 kDa) bound to alpha-chain hGM-CSF receptor fragment (2 kDa, Kd = 35 microM), proline rich peptide (1.5 kDa) bound to fynSH3 domain (8 kDa, Kd = 28 microM), tumour imaging peptide (2 kDa) bound to mucin antigenic fragment (2 kDa, Kd = 20 microM), monoclonal antibody (150 kDa) bound to antigenic protein (120 kDa, Kd = 50 nM). Reconstitution of Cytochrome b5 (Cyt b5) from apo-Cyt b5 and hemin (Kd = 1.6 nM), correct protein folding of reconstituted porphobilinogen deaminase from apo-cofactorless form achieved using the product of the enzyme catalysis, preuroporphyrinogen, rather than porphobilinogen substrate. Competition studies of bound non-chiral drugs diclofenac and diazepam to carrier proteins such as HSA in the presence of fatty acids are few of the examples of the studies carried out by NILIA-CD spectroscopy. The CD changes in either backbone, aromatic side-chains and disulphide regions were used accordingly to screen qualitatively and quantitatively ligand binding in vitro. CD data were fitted by non-linear regression to the general equilibrium reaction of a single-binding site. NILIA-CD is fast compared to NMR, gives information on conformational changes due to interaction, avoids masking of the binding site due to immobilisation and requires no radiolabelling. NILIA-CD is thus an ideal technique for interaction, activity, screening studies.
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PMID:Biomolecules interactions and competitions by non-immobilised ligand interaction assay by circular dichroism. 978 30

Cosalane is a potent inhibitor of HIV replication with multiple sites of action. The purposes of this study were to (a) determine the extent and nature of cosalane binding to mucin, alpha(1)-acid glycoprotein (AAG), plasma, and human (HSA) and bovine serum (BSA) albumin, and (b) determine the primary site(s) of cosalane binding to HSA. Plasma protein binding of cosalane was studied by a gel filtration technique. Cosalane binding to HSA was also determined in the presence of salicylic acid. Competitive inhibition studies were conducted using warfarin, digitoxin, and diazepam to determine the primary HSA binding site(s) of cosalane. The drug was bound extensively to HSA and BSA and required 500-550 moles to saturate 1 mole of protein. Stoichiometries of cosalane binding to alpha(1)-acid glycoprotein (AAG) and mucin were between 30 and 50 mol/mol of either glycoprotein. The binding isotherm deviated from a rectangular hyperbola, suggesting self-association of the ligand. Salicylic acid decreased cosalane binding to HSA by one order of magnitude. Inhibition studies of cosalane to HSA revealed that the compound binds primarily to warfarin site with a K(i) of 1.24 +/- 0.24 nM. In summary, cosalane binds extensively to serum albumins and to a lesser extent to both AAG and mucin.
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PMID:Binding of cosalane--a novel highly lipophilic anti-HIV agent--to albumin and glycoprotein. 1128 10

A research effort is undertaken to understand the mechanism of metal release from, e.g., inhaled metal particles or metal implants in the presence of proteins. The effect of protein adsorption on the metal release process from oxidized chromium metal surfaces and stainless steel surfaces was therefore examined by quartz crystal microbalance with energy dissipation monitoring (QCM-D) and graphite furnace atomic absorption spectroscopy (GFAAS). Differently charged and sized proteins, relevant for the inhalation and dermal exposure route were chosen including human and bovine serum albumin (HSA, BSA), mucin (BSM), and lysozyme (LYS). The results show that all proteins have high affinities for chromium and stainless steel (AISI 316) when deposited from solutions at pH 4 and at pH 7.4 where the protein adsorbed amount was very similar. Adsorption of albumin and mucin was substantially higher at pH 4 compared to pH 7.4 with approximately monolayer coverage at pH 7.4, whereas lysozyme adsorbed in multilayers at both investigated pH. The protein-surface interaction was strong since proteins were irreversibly adsorbed with respect to rinsing. Due to the passive nature of chromium and stainless steel (AISI 316) surfaces, very low metal release concentrations from the QCM metal surfaces in the presence of proteins were obtained on the time scale of the adsorption experiment. Therefore, metal release studies from massive metal sheets in contact with protein solutions were carried out in parallel. The presence of proteins increased the extent of metals released for chromium metal and stainless steel grades of different microstructure and alloy content, all with passive chromium(III)-rich surface oxides, such as QCM (AISI 316), ferritic (AISI 430), austentic (AISI 304, 316L), and duplex (LDX 2205).
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PMID:Adsorption and protein-induced metal release from chromium metal and stainless steel. 2201 96

Mouse strain-specific differences in the carbohydrate composition of intestinal mucins were hypothesized to account for strain-dependent susceptibility to Entamoeba histolytica. To test this hypothesis, intestinal mucins from susceptible and resistant inbred strains of mice were analyzed for their O-glycan content and for their ability to inhibit amoebic adherence to (GalNAc)12-27-HSA neo-glycoproteins. The results showed that the colorectal mucin O-glycan of susceptible CBA mice was lower in sialic acid content than that of resistant C57BL/6 and BALB/c mice. Mucins from CBA mice were more potent inhibitors of E. histolytica adherence to neo-glycoproteins than were mucins from C57BL/6 or BALB/c mice. Consistent with the role of terminal Gal/GalNAc as a receptor for amoebic adherence, sialidase treatment of C57BL/6 and BALB/c colorectal mucins increased their ability to inhibit E. histolytica adherence to the neo-glycoproteins. These results provide evidence of mouse strain-specific differences in the sialic acids content of mucin O-glycans. These dissimilarities likely contribute to the differential susceptibility of the three mouse strains to E. histolytica infection.
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PMID:Sialic acid-dependent attachment of mucins from three mouse strains to Entamoeba histolytica. 2372 13


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