Polymorphonuclear neutrophils (PMNs) are the most abundant circulating leukocytes, and the first cells recruited to sites of tissue inflammation. Using a fixation method to preserve native CD marker expression prior to immunophenotyping, we identified a distinct population of “primed for recruitment” PMNs in healthy mouse and human blood that has high expression of adhesion and activation markers compared with the bulk resting-state PMNs. In response to acute tissue inflammation, primed PMNs (pPMNs) were rapidly depleted from the circulation and recruited to the tissue. One hour after acute peritoneal insult, pPMNs became the dominant PMN population in bone marrow (BM) and blood, returning to baseline levels with resolution of inflammation. PMN priming was induced by the granulopoietic factors granulocyte-macrophage–colony-stimulating factor (GM-CSF) and granulocyte–colony-stimulating factor (G-CSF). High levels of pPMNs were observed in neutropenic mice and in pediatric neutropenic patients who were resistant to infection, highlighting an important role of this population in innate immune function.
Oral microbial habitat is composed of wide variety of species. These species play a significant role in maintaining the well being of the oral cavity by contributing in various ways. However the proper functioning of these oral microbes can be detrimental for the human oral cavity if the conditions are not suitable such as redox potential (Eh), pH of a site, the activity of the host defenses, and the presence of antimicrobial agents. The oral microbial community represents the best-characterized group associated with the human host. There are strong correlations between the qualitative composition of the oral microbiota and clinically healthy or diseased states. Amongst the bacteria of more than 700 species now identified within the human oral microbiota, it is the streptococci that are numerically predominant. Interactions between mucosal surfaces and microbial microbiota are key to host defense, health, and disease. These surfaces are exposed to high numbers of microbes and must be capable of distinguishing between those that are beneficial or avirulent and those that will invade and cause disease. Our understanding of the mechanisms involved in these discriminatory processes has recently begun to expand as new studies bring to light the importance of epithelial cells and novel immune cell subsets such as T(h)17 T cells in these processes. In this review article we have tried to find out the factors responsible for maintaining oral microbial habitat intact and the reasons which cause changes in its composition.
In this disadvantaged population with poor oral hygiene, diabetes has had a strongly negative influence on oral health: diabetic patients have fewer teeth, more plaque, and a higher prevalence of moderate to severe periodontal disease than non-diabetics.
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