Transcriptional profiling studies have also shown that treatment of human neutrophils with IL-8 alone had an effect on many genes encoding signal transducers, membrane receptors and transcriptional factors, thus effecting the response of neutrophils to the external milieu [10]. compared to the AM infected with H37Rv alone. Taken together, these data suggest that neutrophil-macrophage interactions may contribute to host defense against contamination. after inhalation of the bacilli by the host [1, 2]. Interleukin-8 (CXCL8; IL-8) is usually produced following contamination of human AM and THP-1 cells with H37Ra, and a significant correlation between the amount of IL-8 protein and the number of neutrophils has also been observed [3]. Significant amounts of IL-8 protein have been found in bronchoalveolar lavage fluid of TB patients, and in supernatants of human monocytes and monocytic cell lines infected with [3, 4]. AM from BCG-vaccinated guinea pigs can also produce significant amounts of IL-8 mRNA and protein following contamination with tuberculosis [5]. IL-8 functions on chemokine receptors that are highly expressed on neutrophils, thereby causing their recruitment and activation [6, 7]. Recombinant human IL-8 (rhIL-8) can primary human peripheral blood neutrophils for enhanced superoxide anion production [8, 9]. Significant synergistic production of IL-1 protein resulted from treatment of human neutrophils by both LPS and rhIL-8 [10]. studies using anti-IL-8 Ab in rabbits Kobe0065 have shown the suppression of the development of a tuberculin skin reaction, i.e., inhibition of accumulation of leukocytes, in rabbit skin [11]. Neutrophils, found in granulomas in humans, guinea pigs and mice [12], are persistently recruited Rabbit Polyclonal to NDUFA3 to the site of mycobacterial contamination [13]. neutrophil depletion studies in mice have resulted in increased susceptibility to bacterial growth in an intravenous model of contamination [14] and enhanced growth of in the lungs [15]. Neutrophil depletion also impaired the ability of the whole blood to restrict growth of BCG and [16]. Furthermore, recent studies have shown the entrapment of by neutrophil extracellular traps but the mycobacteria were not killed [17]. However, the ability of neutrophils to kill is still controversial [18, 19]. Although neutrophils are terminally differentiated, when stimulated with bacteria, LPS or cytokines they can produce Kobe0065 an array of cytokines and chemokines such as IL-1, IL-8, TGF-, TNF- , MIP-1/, MCP-1 and GRO- in mice, humans and guinea pigs [5, 20, 21]. studies have shown that contamination of guinea pig neutrophils with H37Rv can induce significant amounts of TNF- and IL-8 protein [22]. Inhibition of Kobe0065 spontaneous apoptosis in BCG infected human neutrophils has been observed [21], while promotion of apoptosis of neutrophils by contamination with H37Rv or H37Ra has also been exhibited [23]. A pro-inflammatory response was induced by human macrophages following uptake of mycobacteria-induced apoptotic neutrophils but not by uninfected apoptotic neutrophils [24]. Uptake of apoptotic neutrophils by human macrophages resulted in decreased survival of in macrophages, apparently due to action of neutrophil granules acquired by the macrophages [25]. Taken together, these observations suggest that neutrophils may be important participants in the early pulmonary response to mycobacterial contamination. AM are the first cells which encounter mycobacteria after inhalation and they are also a major source of the IL-8 which is responsible for the recruitment of neutrophils to the site of contamination [1C3, 5]. In turn, cytokines produced by neutrophils (e.g., TNF) may have paracrine effects on AM and other lung cells [22]. Therefore, to further evaluate the importance of the interactions between neutrophils and AM in host defense against tuberculosis in the highly relevant guinea pig model of pulmonary disease, the effect of recombinant guinea pig (rgp) IL-8-activated neutrophils on AM infected with H37Rv was investigated in non-contact co-cultures. Furthermore, we decided the effect of uptake of infected, apoptotic neutrophils around the anti-mycobacterial functions of AM. Materials and methods Animals Specific-pathogen-free outbred Hartley strain guinea pigs (Charles River Breeding Laboratory Inc., Wilmington, Mass.) were individually housed in.