title: Particle size and traffic of phagocytes between the turbot peritoneal cavity and lymphoid organs.
abstract: New adjuvants based on microparticles are being developed for use in fish vaccines. The size of the microparticles may affect the immune response generated, as the adjuvant can either be retained at the site of injection or transported to lymphoid organs. The objectives of this study were to evaluate the maximum size of particles that can be exported out of the cavity, to determine the phagocytosis kinetics and to establish the routes whereby particle-containing cells move from the peritoneal cavity after injection. Fish were injected intraperitoneally with fluorescent cyclodextrins or with fluorescent particles of different size (0.1-10 μm). Phagocytes containing beads of size 4 μm or larger did not reach lymphoid organs, although some were able to cross the peritoneal mesothelium. The number of free peritoneal neutrophils and macrophage-like cells containing beads peaked at 6 and 24 h respectively, and the numbers then decreased quickly, indicating migration of cells to the peritoneum or other body areas. Migration of cells containing beads mainly occurs through the visceral peritoneum. These cells were found on the latero-ventral surfaces of the peritoneal folds that connect the visceral organs. Except for some vascularised areas, the surfaces of liver, stomach and intestine were devoid of particle-containing cells. Some cells containing beads were also found attached to the parietal peritoneum, although in lower numbers than in the visceral peritoneum. Such cells were also found in high numbers in the spleen and kidney 6 h post injection. Because cells containing phagocytosed material quickly become attached to the peritoneum or migrate to lymphoid organs, the immune response generated by a vaccine or by an inflammatory stimulus should probably be evaluated in attached cells as well as in free peritoneal cells.
authors.affiliation: Departamento de Biología Celular y Ecología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Folgueira
authors.affiliation: Departamento de Biología Celular y Ecología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Noia
authors.affiliation: Departamento de Biología Celular y Ecología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors.forename: V
authors.initials: V
authors.lastname: Blanco-Abad
authors.affiliation: Laboratorio de Parasitología, Instituto de Investigación y Análisis Alimentarios, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Mallo
authors.affiliation: Laboratorio de Parasitología, Instituto de Investigación y Análisis Alimentarios, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Leiro
authors.affiliation: Departamento de Biología Celular y Ecología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain. Electronic address: jesus.lamas@usc.es.
authors.forename: J
authors.initials: J
authors.lastname: Lamas
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002465:Cell Movement / Q000276:immunology*; D005412:Flatfishes / Q000276:immunology*; D008221:Lymphoid Tissue / Q000166:cytology* / Q000276:immunology; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D010316:Particle Size; D010529:Peritoneal Cavity / Q000166:cytology*; D010586:Phagocytes / Q000276:immunology*; D013997:Time Factors; D014612:Vaccines / Q000378:metabolism*; D047392:beta-Cyclodextrins
chemical_list: D014612:Vaccines; D047392:beta-Cyclodextrins; C031215:betadex
keywords: Adjuvant; Fish; Microparticles; Migration; Peritoneum; Phagocytes