title: Parasitological and immunological aspects of early Ascaris spp. infection in mice.
abstract: Studies related to the immunobiological aspects of an Ascaris spp. infection are still scarce, especially those that aim to elucidate the early events of the immune response. In this study, we demonstrated a novel standardized method for early experimental Ascaris infection, providing additional information about the infectivity of eggs embryonated in vitro as well as the influence of host age on development of the infection. Finally, we characterised the immunopathology of early infection, focusing on the tissue and systemic cytokine profiles and the histopathology of infection in the lungs of BALB/c mice. Our results demonstrated that the highest egg infectivity occurred on the 100th and 200th days of in vitro embryonation and that 8 week-old BALB/c mice were more susceptible to infection than 16 week-old mice. Ascaris-infected mice showed an early, significant level of IL-5 production in the lungs 4 days p.i., followed by an increase in the level of neutrophils in the inflammatory infiltrate at 8 days p.i, which was correlated with the peak of larval migration in the tissue and a significant level of IL-6 production. The inflammatory infiltrate in the lungs was gradually replaced by mononuclear cells and eosinophils on the 10th and 12th days p.i., respectively, and an increase in TNF levels was observed. The downmodulation of systemic TCD4(+) cell numbers might suggest that T cell hyporesponsiveness was induced by the Ascaris spp. larvae, contributing to safeguarding parasite survival during larval migration. Taken together, the novel aspects of Ascaris infection presented here enabled a better understanding of the immunopathological events during larval migration, providing insight for further studies focused on immunisation and immunoprophylatic assays.
authors.affiliation: Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brasil.
authors.forename: Pedro Henrique
authors.initials: PH
authors.lastname: Gazzinelli-Guimarães
authors.forename: Ana Clara
authors.initials: AC
authors.lastname: Gazzinelli-Guimarães
authors.forename: Flaviane Nunes
authors.initials: FN
authors.lastname: Silva
authors.forename: Vitor Luís Tenório
authors.initials: VL
authors.lastname: Mati
authors.forename: Lucas de Carvalho
authors.initials: Lde C
authors.lastname: Dhom-Lemos
authors.forename: Fernando Sérgio
authors.initials: FS
authors.lastname: Barbosa
authors.forename: Lívia Silva Araújo
authors.initials: LS
authors.lastname: Passos
authors.forename: Soraya
authors.initials: S
authors.lastname: Gaze
authors.forename: Cláudia Martins
authors.initials: CM
authors.lastname: Carneiro
authors.forename: Daniella Castanheira
authors.initials: DC
authors.lastname: Bartholomeu
authors.forename: Lilian Lacerda
authors.initials: LL
authors.lastname: Bueno
authors.forename: Ricardo Toshio
authors.initials: RT
authors.lastname: Fujiwara
mesh_terms: D000375:Aging; D000818:Animals; D001196:Ascariasis / Q000276:immunology* / Q000469:parasitology* / Q000473:pathology; D017165:Ascaris suum; D007422:Intestines / Q000469:parasitology; D008099:Liver / Q000469:parasitology; D008168:Lung / Q000469:parasitology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010063:Ovum
keywords: Ascaris infection; Cytokine profile; Immune response; Immunopathology; Inflammation; Murine model