{"id":"05ebf8b1-d743-59a8-ba02-36ab188b07e5","stable_key":"7fc92b9e-9cbf-556e-8719-6b5244625250:b12-abs-if-antibody-preformed-complex","predicate":"inhibits","statement":"Type II antibodies prevented absorption in pernicious-anemia patients when added to a preformed intrinsic-factor-B12 complex.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"negative","is_public":true,"mechanism_event_id":"01c2cacc-6253-5c09-a9b8-9bab010b2edb","mechanism_event_label":"Other antibodies interfered even after B12 had bound its carrier.","subject":{"id":"64f24b8a-e919-5bbf-bb6e-20a160e8d72b","slug":"human-if-type-ii-autoantibodies","display_name":"Human type II intrinsic-factor binding autoantibodies","entity_type_key":"protein_family"},"object":{"id":"8c0f397a-9cad-554f-ac5b-bb51bf1be2ac","slug":"intestinal-cobalamin-absorption","display_name":"Intestinal cobalamin absorption","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"01c2cacc-6253-5c09-a9b8-9bab010b2edb","stable_key":"7fc92b9e-9cbf-556e-8719-6b5244625250:b12-abs-if-antibody-preformed-complex-event","event_type":"biochemical_relationship","label":"Other antibodies interfered even after B12 had bound its carrier.","description":"Type II antibodies prevented absorption in pernicious-anemia patients when added to a preformed intrinsic-factor-B12 complex.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"b6d9b937-895d-5e0a-8cc5-0454a0b7d373","slug":"vitamin-b12","display_name":"Vitamin B12 (cobalamins)","entity_type_key":"chemical_species"},"role":"nutrient","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"490161eb-b7f8-56b6-82bc-77c8c0bdc1ca","slug":"gif","display_name":"Human gastric intrinsic factor / GIF","entity_type_key":"protein"},"role":"antibody-target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"1e7fbe30-20c5-5229-97de-84ad5c3dde84","slug":"human-if-cobalamin","display_name":"Human intrinsic factor-cobalamin complex","entity_type_key":"protein_complex"},"role":"preformed-ligand","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"64f24b8a-e919-5bbf-bb6e-20a160e8d72b","slug":"human-if-type-ii-autoantibodies","display_name":"Human type II intrinsic-factor binding autoantibodies","entity_type_key":"protein_family"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"8c0f397a-9cad-554f-ac5b-bb51bf1be2ac","slug":"intestinal-cobalamin-absorption","display_name":"Intestinal cobalamin absorption","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""}]},"contexts":[{"dimension":"availability_state","value_text":"machinery_impairment","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null},{"dimension":"cross_nutrient","value_text":"false","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Human absorption experiments with preassembled IF-B12","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"IF plus B12 followed by type II antibody","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Demonstrates impaired absorption; does not identify an epitope or directly prove contact competition at cubilin.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"vitamin-b12","display_name":"Vitamin B12 (cobalamins)","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Other antibodies interfered even after B12 had bound its carrier.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[schade-1967-if-antibody] Studies on antibody to intrinsic factor. (1967). https://pubmed.ncbi.nlm.nih.gov/6021209/ DOI: 10.1172/jci105563","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Intestinal intrinsic-factor-dependent absorption","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"trigger_kind","value_text":"machinery_impairment","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null}],"evidence":[{"id":"98ba28ce-b0f9-5be7-89f7-4643793c1c62","evidence_kind":"source_excerpt","locator":"Lines 517-528","start_line":517,"end_line":528,"excerpt":"### b12-abs-if-antibody-preformed-complex\nType II antibodies prevented absorption in pernicious-anemia patients when added to a preformed intrinsic-factor-B12 complex.\nCondition category: machinery_impairment\nnutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Other antibodies interfered even after B12 had bound its carrier.\norganism: Homo sapiens\ntissue_or_cell_type: Intestinal intrinsic-factor-dependent absorption\nexperimental_model: Human absorption experiments with preassembled IF-B12\nlimitations: Demonstrates impaired absorption; does not identify an epitope or directly prove contact competition at cubilin.\nexposure: IF plus B12 followed by type II antibody\ncross_nutrient: false\n[schade-1967-if-antibody] Studies on antibody to intrinsic factor. (1967). https://pubmed.ncbi.nlm.nih.gov/6021209/ DOI: 10.1172/jci105563","model_system":"Human absorption experiments with preassembled IF-B12","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [schade-1967-if-antibody] Studies on antibody to intrinsic factor. (1967). https://pubmed.ncbi.nlm.nih.gov/6021209/ DOI: 10.1172/jci105563","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"73145023-2982-5848-aff2-8d8875d6b9c5","stable_key":"import-7fc92b9e-9cbf-556e-8719-6b5244625250","title":"Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text.","file_path":"","sha256":"ad5b3a51d36e856aa7fdfd1cc23f690b094689bad87d28e1a621a54675a01c92","revision_id":"118bd616-0c13-549f-bfeb-bc439715b89c","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}