title: Cryogenic transmission electron microscopy of recombinant tuberculosis vaccine antigen with anionic liposomes reveals formation of flattened liposomes.
abstract: Development of lipid-based adjuvant formulations to enhance the immunogenicity of recombinant vaccine antigens is a focus of modern vaccine research. Characterizing interactions between vaccine antigens and formulation excipients is important for establishing compatibility between the different components and optimizing vaccine stability and potency. Cryogenic transmission electron microscopy (TEM) is a highly informative analytical technique that may elucidate various aspects of protein- and lipid-based structures, including morphology, size, shape, and phase structure, while avoiding artifacts associated with staining-based TEM. In this work, cryogenic TEM is employed to characterize a recombinant tuberculosis vaccine antigen, an anionic liposome formulation, and antigen-liposome interactions. By performing three-dimensional tomographic reconstruction analysis, the formation of a population of protein-containing flattened liposomes, not present in the control samples, was detected. It is shown that cryogenic TEM provides unique information regarding antigen-liposome interactions not detectable by light-scattering-based methods. Employing a suite of complementary analytical techniques is important to fully characterize interactions between vaccine components.
authors.affiliation: Infectious Disease Research Institute, Seattle, WA, USA.
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Fox
authors.affiliation: NanoImaging Services, La Jolla, CA, USA.
authors.forename: Sean K
authors.initials: SK
authors.lastname: Mulligan
authors.affiliation: NanoImaging Services, La Jolla, CA, USA.
authors.forename: Joyce
authors.initials: J
authors.lastname: Sung
authors.affiliation: Infectious Disease Research Institute, Seattle, WA, USA.
authors.forename: Quinton M
authors.initials: QM
authors.lastname: Dowling
authors.affiliation: Infectious Disease Research Institute, Seattle, WA, USA.
authors.forename: H W Millie
authors.initials: HW
authors.lastname: Fung
authors.affiliation: Infectious Disease Research Institute, Seattle, WA, USA.
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Vedvick
authors.affiliation: Infectious Disease Research Institute, Seattle, WA, USA.
authors.forename: Rhea N
authors.initials: RN
authors.lastname: Coler
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000818:Animals; D000942:Antigens, Bacterial / Q000737:chemistry* / Q000648:ultrastructure; D020285:Cryoelectron Microscopy; D006801:Humans; D021621:Imaging, Three-Dimensional; D008081:Liposomes / Q000008:administration & dosage / Q000737:chemistry; D050997:Nanomedicine; D053758:Nanoparticles / Q000008:administration & dosage / Q000737:chemistry; D010316:Particle Size; D032581:Tuberculosis Vaccines / Q000008:administration & dosage / Q000737:chemistry / Q000276:immunology*; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000737:chemistry / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D000942:Antigens, Bacterial; D008081:Liposomes; D032581:Tuberculosis Vaccines; D014614:Vaccines, Synthetic
keywords: 3D tomographic reconstruction; antigen-adjuvant interactions; cryo-TEM; vaccine adjuvant; vaccine formulation morphology; vaccine physical characterization