ECE2017 Eposter Presentations: Pituitary and Neuroendocrinology Growth hormone IGF axis - basic (10 abstracts)
A surprising and dramatic neuroendocrine-immune phenotype of mice deficient in Growth Hormone-Releasing Hormone (GHRH)
Khalil Farhat 1 , Gwennaëlle Bodart 1 , Chantal Renard 1 , Christophe Desmet 2 , Michel Moutschen 3 , Frédéric Baron 4 , Yves Beguin 4 , Roberto Salvatori 5 , Henri Matens 1 & Vincent Geenen 1
1GIGA-I3-Immunoendocrinology, University of Liege, Liege, Belgium; 2GIGA-I3-Cellular and Molecular Immunology, University of Liege, Liege, Belgium; 3GIGA-I3-Immunology and Infectious Diseases, University of Liege, Liege, Belgium; 4GIGA-I3-Hematology, University of Liege, Liege, Belgium; 5Division of endocrinology Diabetes and metabolis, John hokins University, Baltimore, Maryland, USA.
In the framework of close interactions between the immune and neuroendocrine systems, Growth Hormone (GH) has been proposed to exert significant effects on the immune system, but there is not yet a consensus about GH immunomodulatory properties. These studies investigated the immune and anti-infectious response of dwarf Ghrh−/− mice presenting a severe deficiency of the GHRH/GH/IGF-1 axis. In basal conditions, thymic parameters and T-cell responses of Ghrh−/− mice were not severely affected but a constant B-cell lymphopaenia was observed. Thus, we investigated vaccine and anti-infectious responses of Ghrh−/− mice toward Streptococcus pneumonia, a B-dependent pathogen, Ghrh−/− mice were unable to trigger production of specific IgM and IgG against serotype 1 pneumococcal polysaccharide (PPS) after vaccination with either native PPS (Pnx23) or protein-PPS conjugate (Prev-13) vaccines. These vaccines both include the serotype 1 (our S. pneumoniae strain) and provide an effective protection in mice. A short GH supplementation to Ghrh−/− mice (1 daily injection of 1 mg/kg GH for 4 weeks) restored IgM and IgG response to Pnx23 vaccine but not to Prev-13. This suggests that GH could exert distinct impacts upon spenic areas. Furthermore, after intranasal instillation of a non-lethal dose (defined by the full clearance by WT C57BL/6 mice after 24 h) of serotype 1 S. pneumoniae, Ghrh-/- mice exhibited a dramatic susceptibility. This was proved by a marked time-dependent increase in pulmonary bacterial, a septicemia already 24 h after infection and a survival limit of 72 h. We also observed a dramatic decrease in lung B- and T-cell populations and an increase in proportion of inflammatory macrophages. By contrast, WT and heterozygote mice completely cleared S. pneumoniae infection after 24 h. In conclusion, our data show without ambiguity that the somatotrope GHRH/GH/IGF-1 axis plays an important and unsuspected role in defense against S. pneumoniae.
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Endocrine Abstracts
ISSN 1470-3947 (print) | ISSN 1479-6848 (online)
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