title: Behavior: a relevant tool for brain-immune system interaction studies.
abstract: Neuroimmunomodulation describes the field focused on understanding the mechanisms by which the central nervous system interacts with the immune system, potentially leading to changes in animal behavior. Nonetheless, not many articles dealing with neuroimmunomodulation employ behavior as an analytical endpoint. Even fewer papers deal with social status as a possible modifier of neuroimmune phenomena. In the described sets of experiments, we tackle both, using a paradigm of social dominance and subordination. We first review data on the effects of different ranks within a stable hierarchical relationship. Submissive mice in this condition display more anxiety-like behaviors, have decreased innate immunity, and show a decreased resistance to implantation and development of melanoma metastases in their lungs. This suggests that even in a stable, social, hierarchical rank, submissive animals may be subjected to higher levels of stress, with putative biological relevance to host susceptibility to disease. Second, we review data on how dominant and submissive mice respond differentially to lipopolysaccharide (LPS), employing a motivational perspective to sickness behavior. Dominant animals display decreased number and frequency in several aspects of behavior, particularly agonistic social interaction, that is, directed toward the submissive cage mate. This was not observed in submissive mice that maintained the required behavior expected by its dominant mate. Expression of sickness behavior relies on motivational reorganization of priorities, which are different along different social ranks, leading to diverse outcomes. We suggest that in vitro assessment of neuroimmune phenomena can only be understood based on the behavioral context in which they occur.
authors.affiliation: Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, Sao Paulo, Brazil. fpinto@usp.br
authors.forename: Frederico Azevedo
authors.initials: FA
authors.lastname: Costa-Pinto
authors.forename: Daniel Wagner Hamada
authors.initials: DW
authors.lastname: Cohn
authors.forename: Vanessa Moura
authors.initials: VM
authors.lastname: Sa-Rocha
authors.forename: Luiz Carlos
authors.initials: LC
authors.lastname: Sa-Rocha
authors.forename: Joao
authors.initials: J
authors.lastname: Palermo-Neto
mesh_terms: D000818:Animals; D001519:Behavior / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D006608:Hierarchy, Social; D006801:Humans; D055809:Illness Behavior; D007107:Immune System / Q000502:physiology*; D007113:Immunity, Innate