Research paper The influence of monogalactosyldiacylglycerols from different marine macrophytes on immunogenicity and conformation of protein antigen of tubular immunostimulating complex Nina M. Sanina a, * , Eduard Y. Kostetsky a , Valery L. Shnyrov b , Alexander V. Tsybulsky a , Olga D. Novikova c , Olga Y. Portniagina c , Natalia S. Vorobieva a , Andrey N. Mazeika a , Mikhail V. Bogdanov d a Department of Biochemistry, Microbiology and Biotechnology, Far Eastern Federal University, Sukhanov St., 8, 690600 Vladivostok, Russia b Departmento de Bioquímica y Biología Molecular, Universidad de Salamanca, 37007 Salamanca, Spain c Pacific Institute of Bioorganic Chemistry, Prospect 100 let Vladivostoku, 159, Vladivostok 690022 Russia d Department of Biochemistry and Molecular Biology, University of Texas-Houston Medical School, Houston, TX, USA article info Article history: Received 23 October 2011 Accepted 11 January 2012 Available online 16 January 2012 Keywords: Lipideprotein interaction Microviscosity Adjuvant Delivery system Porin YOmpF abstract The tubular immunostimulating complex (TI-complex) is a novel nanoparticulate antigen delivery system consisting of cholesterol, triterpene glycoside cucumarioside A 2 -2, and glycolipid monogalacto- syldiacylglycerol (MGDG) isolated from marine macrophytes. MGDG is crucial for the formation of a lipid matrix for the protein antigen incorporated in TI-complexes. Fatty acid composition and the physical state of this glycolipid depend on the taxonomic position of marine macrophytes. Therefore, the aim of the present work was to study the capacity of MGDGs, isolated from five species of marine macrophytes, to influence conformation and to enhance immunogenicity of porin from Yersinia pseudotuberculosis (YOmpF) as a model antigen of subunit vaccine based on TI-complexes. The trimeric porin was chosen for these experiments, because it was approximately two times more immunogenic than monomeric porin incorporated in TI-complexes. Immunization of mice with YOmpF within TI-complexes, comprised of different MGDGs, revealed a dependence of the immunostimulating effect of TI-complexes on the microvicosity of this glycolipid. TI-complexes comprising MGDGs from Sargassum pallidum and Ulva fenestrata with medium microviscosity induced maximal levels of anti-porin antibodies (four times higher when compared with those induced by pure porin). The adjuvant effect of TI-complexes based on other MGDGs varied by 2.8, 2.3 and 1.3 times for TI-complexes comprised of MGDGs from Zostera marina, Ahnfeltia tobuchiensis, and Laminaria japonica, respectively. MGDGs are also able to influence cytokine mechanisms of immunological regulation. DSC and spectroscopic studies showed that maximal immu- nostimulating effect of TI-complexes correlated with a moderate stabilizing influence of MGDGs from S. pallidum and U. fenestrata on the conformation of porin. The results obtained suggest lipid “nanofluidics” as a novel strategy for optimizing the immune response to protein antigens within lipid particulate systems. Ó 2012 Elsevier Masson SAS. All rights reserved. 1. Introduction New vaccine generations, based on isolated antigens, allow induction of highly specific immune responses to microbial path- ogens. However, most purified antigens have insufficient immu- nogenicity. Significant efforts are currently being made to search for safe and effective adjuvants and to develop new techniques for presentation of antigens to immunocompetent cells. Nevertheless, the development of effective and biodegradable adjuvants approved for the vaccination of humans and animals against infectious diseases remains a very important and as yet unmet need [1]. Nanoparticulate ISCOMs, consisting of a phospholipid matrix for the antigen, cholesterol, and the saponin Quil A, offer one of the most promising adjuvant-delivery systems, the efficiency of which is remarkably higher than that of liposomes and attenuated viral vaccines [2]. ISCOMs induce both humoral and cell-mediated immune responses against pathogenic microorganisms; however, unfortunately, they demonstrate their own hemolytic toxicity due to the presence of Quil A triterpene glycosides. * Corresponding author. Tel.: þ7 4232 257779; fax: þ7 4232 429510. E-mail addresses: sanina@bio.dvgu.ru (N.M. Sanina), shnyrov@usal.es (V.L. Shnyrov), novolga_05@mail.ru (O.D. Novikova), mikhail.v.bogdanov@ uth.tmc.edu (M.V. Bogdanov). Contents lists available at SciVerse ScienceDirect Biochimie journal homepage: www.elsevier.com/locate/biochi 0300-9084/$ e see front matter Ó 2012 Elsevier Masson SAS. All rights reserved. doi:10.1016/j.biochi.2012.01.009 Biochimie 94 (2012) 1048e1056