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Neonatal Bacterial Infection
Published in K. Balamurugan, U. Prithika, Pocket Guide to Bacterial Infections, 2019
Koilmani Emmanuvel Rajan, Christopher Karen
However, the macrophages and dendritic cells are present in the tissues lining the CSF, namely, leptomeninges, choroid plexus, and perivascular spaces that function as sentinel cells. Sentinel cells through PRRs help to recognize the bacteria in CSF. Some PRRs expressed can act as a macrophage scavenger receptor, the mannose receptor, and complement receptors. They bind to the bacteria, thus mediating their internalization by phagocytes. While in brain, toll-like receptors (TLRs) are present in the immunocompetent cells. These make the CSF more susceptible and suppress the immune reactivity. When bacteria invade the CSF, they can easily proliferate and spread throughout the brain without any hindrance (Grandgirard and Leib 2010; Koedel et al. 2010). The bacterial concentration in infected CSF can reach a similar value to the bacterial concentration of the broth-culture in vitro (Small et al. 1986).
The maternal immune system during pregnancy
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Online, 2021
The innate arm of the immune system is the first line of defense and includes (i) epithelial cells, (ii) macrophages, (iii) neutrophils, (iv) natural killer (NK) cells, and (v) complement. Innate sentinel cells include epithelial cells and macrophages that sample the local environment and rapidly respond when pathogens are detected. Neutrophils and NK cells are the primary effector cells of the innate immune system. Eosinophils and basophils play an important role in allergic and parasitic infections and will not be discussed in detail in this chapter. Serum complement does just that—“complement” immune processes by weakening or marking pathogens for destruction.
In this issue: Role of specific and non-specific immunity in disease
Published in International Reviews of Immunology, 2018
The innate sentinel cells express various families of pattern recognition receptors (PRRs) which sense unique biomolecules associated with pathogen known as pathogen-associated molecular patterns (PAMPs), to induce appropriate immune responses. The first two review articles of this issue by Dolasia et al. and Vidya et al broadly focus on PRRs and role in shaping the pathogen-specific adaptive immunity mediated through B and T lymphocytes. The first review article by Dolasia et al. discusses the effector immune responses induced upon sensing of microbial pathogens by Toll-like receptors(TLRs) and NOD-like receptors (NLRs). The authors highlighted the potential of TLRs/NLRs ligand based therapeutics. The second review article by Vidya et al. describes the different PAMPs sensed by TLRs and the various molecules involve in signaling to activate key transcription factors and MAP kinases to induce an anti-microbial state. The authors also discuss the influence of host genetics in the development of innate immune responses. Collectively, both articles proposed development of PRR ligand-based therapeutics and corresponding diagnostics for infectious diseases (Figure 1).
Dendritic Cells Currently under the Spotlight; Classification and Subset Based upon New Markers
Published in Immunological Investigations, 2021
Samaneh Soltani, Mahdi Mahmoudi, Elham Farhadi
In late 2011, the Nobel Prize laureate in Physiology or Medicine, Prof. Ralph Steinman, was honored for his efforts in the identification of dendritic cells (DCs) and determining their function in adaptive immunity. These cells are specialized sentinel cells that initiate both the innate and adaptive immune responses (Liu and Cao 2015). As they are rarely seen in circulation, they usually comprise 1% or less of whole hematopoietic cells (O’Keeffe et al. 2015). DCs, which are considered as surveillant cells, consist of different subsets (Clark et al. 2019).