{"doi":"10.1007/bf01789046","title":"Blocked and non-blocked ricin immunotoxins against the CD4 antigen exhibit higher cytotoxic potency than a ricin A chain immunotoxin potentiated with ricin B chain or with a ricin B chain immunotoxin","abstract":null,"journal":"Cancer Immunology Immunotherapy","year":1991,"id":687831,"datarank":0.515098080672772,"base_score":3.4339872044851463,"endowment":3.4339872044851463,"self_citation_contribution":0.515098080672772,"citation_network_contribution":0.0,"self_endowment_contribution":0.515098080672772,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":30,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1796923,"name":"Graham J. Watson","orcid":null,"position":1,"is_corresponding":false},{"id":1796924,"name":"Alan J. Cumber","orcid":null,"position":2,"is_corresponding":false},{"id":1796925,"name":"Raymond V. Henry","orcid":null,"position":3,"is_corresponding":false},{"id":1796926,"name":"Geoffrey D. Parnell","orcid":null,"position":4,"is_corresponding":false},{"id":1515891,"name":"E. Peter Rieber","orcid":null,"position":5,"is_corresponding":false},{"id":1184992,"name":"Philip E. Thorpe","orcid":null,"position":6,"is_corresponding":false},{"id":1796922,"name":"Edward J. Wawrzynczak","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"resolved":true,"title":"Blocked and non-blocked ricin immunotoxins against the CD4 antigen exhibit higher cytotoxic potency than a ricin A chain immunotoxin potentiated with ricin B chain or with a ricin B chain immunotoxin","abstract":"An immunotoxin consisting of ricin A chain linked to the monoclonal antibody M-T151, recognising the CD4 antigen, was weakly toxic to the human T-lymphoblastoid cell line CEM in tissue culture. The incorporation of [3H]leucine by CEM cells was inhibited by 50% at an M-T151--ricin-A-chain concentration (IC50) of 4.6 nM compared with an IC50 of 1.0 pM for ricin. In contrast, immunotoxins made by linking intact ricin to M-T151 in such a way that the galactose-binding sites of the B chain subunit were either blocked sterically by the antibody component or were left unblocked, were both powerfully cytotoxic with IC50 values of 20-30 pM. The addition of ricin B chain to CEM cells treated with M-T151--ricin-A-chain enhanced cytotoxicity by only eight-fold indicating that isolated B chain potentiated the action of the A chain less effectively than it did as an integral component of an intact ricin immunotoxin. Ricin B chain linked to goat anti-(mouse immunoglobulin) also potentiated weakly. Lactose completely inhibited the ability of isolated ricin B chain to potentiate the cytotoxicity of M-T151--ricin-A-chain and partially (3- to 4-fold) inhibited the cytotoxicity of the blocked and non-blocked ricin immunotoxins. Thus, in this system, the galactose-binding sites of the B chain contributed to cell killing regardless of whether isolated B chain was associated with the A chain immunotoxin or was present in blocked or non-blocked form as part of an intact ricin immunotoxin. The findings suggest that the blocked ricin immunotoxin may become unblocked after binding to the target antigen to re-expose the cryptic galactose-binding sites. However, the unblocking cannot be complete because the maximal inhibition of [3H]leucine incorporation by the blocked immunotoxin was only 80% compared with greater than 99% inhibition by the non-blocked immunotoxin.","is_dataset_classified":null,"base_score":3.4339872044851463,"endowment":3.4339872044851463,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"1998970","pmcid":"PMC11038860","openalex_id":"https://openalex.org/W2025367936","authors":[],"funders":[],"total_grants":0,"fwci":1.9112,"citation_percentile":0.86821953,"influential_citations":0,"citation_trend":[{"year":2013,"count":1},{"year":2014,"count":1},{"year":2015,"count":1},{"year":2017,"count":2},{"year":2019,"count":1},{"year":2023,"count":1},{"year":2025,"count":1}],"oa_status":"green","license":"http://www.springer.com/tdm","oa_locations":[{"url":"https://www.ncbi.nlm.nih.gov/pmc/articles/11038860","host_type":"repository"},{"url":"https://www.ncbi.nlm.nih.gov/pmc/articles/11038860","host_type":"repository"},{"url":"http://link.springer.com/content/pdf/10.1007/BF01789046.pdf","host_type":"publisher"},{"url":"http://link.springer.com/article/10.1007/BF01789046/fulltext.html","host_type":"publisher"},{"url":"http://link.springer.com/content/pdf/10.1007/BF01789046","host_type":"publisher"},{"url":"https://doi.org/10.1007/bf01789046","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/1998970","host_type":"repository"}],"fields_of_study":["Toxin Mechanisms and Immunotoxins","Transgenic Plants and Applications","Plant tissue culture and regeneration","Animals","Antibodies, Monoclonal","B-Lymphocytes","Binding Sites","Binding, Competitive","CD4 Antigens","Cell Survival","Cells, Cultured","Galactose","Goats","Humans","Immunotoxins","Lactose","Mice","Neoplasms","Peptides","Ricin","T-Lymphocytes","Tumor Cells, Cultured"],"mesh_terms":["Animals","Antibodies, Monoclonal","Immunotoxins","B-Lymphocytes","Binding Sites","Binding, Competitive","Cell Survival","Cells, Cultured","Galactose","Goats","Humans","Lactose","Neoplasms","Peptides","Ricin","T-Lymphocytes","Tumor Cells, Cultured","CD4 Antigens","Mice"],"keywords":["Ricin","Immunotoxin","Cytotoxicity","Molecular biology","Chemistry","Immunoglobulin light chain","Cytotoxic T cell","Antibody","Monoclonal antibody","Toxin","Biochemistry","In vitro","Biology","Immunology"],"sdg_mappings":[],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-08-18T23:08:16.440815Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}