title: Enhanced structural stability of Concholepas hemocyanin increases its immunogenicity and maintains its non-specific immunostimulatory effects.
abstract: Hemocyanins, which boost the immune system of mammals, have been used as carrier-adjuvants to promote Ab production against haptens and peptides, as immunostimulants during therapy for bladder carcinoma and as a component in therapeutic vaccines for cancer. These biomedical applications have led to growing interest in obtaining hemocyanins with high immunogenicity. Here, we study the immunological properties of a modified oxidized Concholepas concholepas hemocyanin (Ox-CCH) obtained by the oxidation of its carbohydrates using sodium periodate. We assessed the internalization of Ox-CCH into DCs and its immunogenicity and antitumor effects. Transmission electron microscopy showed no changes in Ox-CCH quaternary structure with respect to native CCH, although proteolytic treatment followed by SDS-PAGE analysis demonstrated that Schiff bases were formed. Interestingly, DCs internalized Ox-CCH faster than CCH, mainly through macropinocytosis. During this process, Ox-CCH remained inside endosome-like structures for a longer period. Mouse immunization experiments demonstrated that Ox-CCH is more immunogenic and a better carrier than CCH. Moreover, Ox-CCH showed a significant antitumor effect in the B16F10 melanoma model similar to that produced by CCH, inducing IFN-γ secretion. Together, these data demonstrate that the aldehydes formed by the periodate oxidation of sugar moieties stabilizes the CCH structure, increasing its adjuvant/immunostimulatory carrier effects.
authors.affiliation: Fundación Ciencia y Tecnología para Desarrollo, Santiago, Chile.
authors.forename: Sergio
authors.initials: S
authors.lastname: Arancibia
authors.forename: Miguel
authors.initials: M
authors.lastname: Del Campo
authors.forename: Esteban
authors.initials: E
authors.lastname: Nova
authors.forename: Fabián
authors.initials: F
authors.lastname: Salazar
authors.forename: María Inés
authors.initials: MI
authors.lastname: Becker
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D003713:Dendritic Cells / Q000276:immunology; D005260:Female; D049851:Gastropoda / Q000276:immunology / Q000378:metabolism*; D006433:Hemocyanins / Q000737:chemistry* / Q000276:immunology / Q000494:pharmacology / Q000648:ultrastructure; D053208:Kaplan-Meier Estimate; D008546:Melanoma, Experimental / Q000188:drug therapy / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D046529:Microscopy, Electron, Transmission; D010084:Oxidation-Reduction; D010504:Periodic Acid / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000276:Adjuvants, Immunologic; D000970:Antineoplastic Agents; D010504:Periodic Acid; D006433:Hemocyanins; C009288:metaperiodate