Neutrophils are involved in the non‐specific resistance to listeriosis induced by mycobacterial infections

Abstract

A major role has been recently ascribed to the neutrophil in the resistance to infection by Listeria monocytogenes (L. monocytogenes). Here we evaluated whether such neutrophils played a role in the non‐specific resistance to listeriosis that develops in hosts infected by mycobacteria. We found that the depletion of neutrophils completely abrogated the resistance conferred by the activated macrophages induced during the mycobacterial infection. The lack of killing by activated Kupffer cells and the visualization of bacteria proliferating inside peritoneal macrophages in neutrophil‐depleted mice allowed us to postulate a role for the cooperation between neutrophils and macrophages in the killing of L. monocytogenes. We also found listerial proliferation in hepatocytes of neutrophil‐depleted, mycobacteria‐infected mice showing that the neutrophils may be involved in the control of listeria infection of parenchymal cells.

Heat-killed BCG induces biphasic cyclooxygenase 2+ splenic macrophage formation—role of IL-10 and bone marrow precursors

“…Increases in immature and mature MA and neutrophil numbers within 5-21 days are observed in animals treated with BCG or P. acnes [9,42]. Our unpublished studies have also shown that depletion of RB6-8C5 ϩ cells by a specific antibody on Day 14 in HK-BCG mice results in unchanged F4/80 ϩ red pulp MA numbers as well as PGE 2 release (data not shown).…”

Immune Response in Human Visceral Leishmaniasis: Analysis of the Correlation Between Innate Immunity Cytokine Profile and Disease Outcome

“…In addition to microbicidal activity, PMN are capable of producing several cytokines. In recent years, neutrophils have been shown to produce cytokines such as TNF‐α and IL‐12 after stimulation with bacterial lipopolysaccharides (LPS) and after infection with Candida albicans or Toxoplasma gondii [34–37]. Nakajima et al .…”

“…In addition to microbicidal activity, PMN are capable of producing several cytokines. In recent years, neutrophils have been shown to produce cytokines such as TNF-a and IL-12 after stimulation with bacterial lipopolysaccharides (LPS) and after infection with Candida albicans or Toxoplasma gondii [34][35][36][37]. Nakajima et al [38] observe that normal human peripheral blood eosinophils can transcribe mRNA for a wide variety of cytokines, including TNF-a, IL-4, IL-5, IL-10 and IFN-g.…”

Splenic PGE2-releasing macrophages regulate Th1 and Th2 immune responses in mice treated with heat-killed BCG

“…Live BCG induces not only host resistance to M. tuberculosis but also tumoricidal activity and has been used widely for treatment of superficial bladder cancer [40,41]. Live BCG also induces a nonspecific MA microbicidal activity against Listeria monocytogenes [42,43] and Toxoplasma gondii [44]. It has been reported that a low dose (0.01 mg) of HK-BCG suspended in saline induced a Th1 lymphocyte response against mycobacteria, but the effects were not sufficient to protect against mycobacterial infections, whereas immunization with HK-mycobacteria in mineral oil (CFA) was protective [45].…”