title: Neutrophils exert a suppressive effect on Th1 responses to intracellular pathogen Brucella abortus.
abstract: Polymorphonuclear neutrophils (PMNs) are the first line of defense against microbial pathogens. In addition to their role in innate immunity, PMNs may also regulate events related to adaptive immunity. To investigate the influence of PMNs in the immune response during chronic bacterial infections, we explored the course of brucellosis in antibody PMN-depleted C57BL/6 mice and in neutropenic mutant Genista mouse model. We demonstrate that at later times of infection, Brucella abortus is killed more efficiently in the absence of PMNs than in their presence. The higher bacterial removal was concomitant to the: i) comparatively reduced spleen swelling; ii) augmented infiltration of epithelioid histiocytes corresponding to macrophages/dendritic cells (DCs); iii) higher recruitment of monocytes and monocyte/DCs phenotype; iv) significant activation of B and T lymphocytes, and v) increased levels of INF-γ and negligible levels of IL4 indicating a balance of Th1 over Th2 response. These results reveal that PMNs have an unexpected influence in dampening the immune response against intracellular Brucella infection and strengthen the notion that PMNs actively participate in regulatory circuits shaping both innate and adaptive immunity.
authors: Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica.
authors: Elías
authors: E
authors: Barquero-Calvo
authors: Anna
authors: A
authors: Martirosyan
authors: Diana
authors: D
authors: Ordoñez-Rueda
authors: Vilma
authors: V
authors: Arce-Gorvel
authors: Alejandro
authors: A
authors: Alfaro-Alarcón
authors: Hubert
authors: H
authors: Lepidi
authors: Bernard
authors: B
authors: Malissen
authors: Marie
authors: M
authors: Malissen
authors: Jean-Pierre
authors: JP
authors: Gorvel
authors: Edgardo
authors: E
authors: Moreno
mesh_terms: D056704:Adaptive Immunity; D000818:Animals; D002003:Brucella abortus / Q000472:pathogenicity*; D002006:Brucellosis / Q000276:immunology* / Q000821:virology; D016207:Cytokines / Q000378:metabolism; D005434:Flow Cytometry; D007113:Immunity, Innate / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009504:Neutrophils / Q000276:immunology* / Q000821:virology; D018417:Th1 Cells / Q000276:immunology* / Q000821:virology
chemical_list: D016207:Cytokines