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 covalently coupled 9-beta-D-arabinofuranosyladenine 5'-monophosphate (ara-AMP) to the carrier molecule lactosaminated human serum albumin using a water-soluble carbodiimide with a two-step conjugation method (pH 4.5 and pH 7.5) instead of the commonly used single-step conjugation at pH 7.5. This resulted in a predominantly monomeric conjugate (lac27-HSA-ara-AMP9). The conjugate was stable in buffer (pH 7.4) and blood plasma. After in vivo injection, the carrier and the monomeric conjugate were subjected to selective endocytosis in rat hepatocytes, as shown on immunohistochemical study and cell-separation techniques using 125I-labeled material. In competition experiments with other ligands for the asialoglycoprotein receptor N-acetylgalactosamine and asialofetuin, we showed that both lactosaminated human serum albumin and lac27-HSA-ara-AMP9 are subject to endocytosis by this receptor system. Although the coupling of ara-AMP significantly increased the net negative charge of the conjugate compared with the native carrier, liver uptake was not affected by coadministration of an excess of succinylated human serum albumin (suc-HSA), a negatively charged ligand for the scavenger receptor. Incubation studies with purified rat liver lysosomes showed that in this acidic and proteolytic environment, mainly ara-AMP and, to a much lesser extent, ara-A itself were released from the carrier. After injection into the rat in vivo and in isolated perfused rat liver, no free ara-AMP or 9-B-D-arabinofuranosyladenine (ara-A) could be detected in plasma and perfusate, respectively, indicating proper retention of the virally active components in hepatocytes.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Coupling of the antiviral drug ara-AMP to lactosaminated albumin leads to specific uptake in rat and human hepatocytes. 768 77

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