The invariant (i) natural killer (NK)T cells represent a unique subset of T lymphocytes which express the V alpha14 chain of the T cell receptor (TCR), that recognizes glycolipid antigens presented by the nonpolymorphic major histocompatibility complex (MHC) class I-like antigen presentation molecule CD1d, and they participate in protection against some microbial pathogens. Although iNKT cells have originally been regarded as T cells co-expressing NKR-P1B/C (NK1.1: CD 161), they do not seem to consistently express this marker, since NK1.1 surface expression on iNKT cells undergoes dramatic changes following facultative intracellular bacterial infection, which is correlated with functional changes of this cell population. Accumulating evidence suggests that NK1.1 allows recognition of "missing-self", thus controling activation/inhibition of NK1.1-expressing cells. Therefore, it is tempting to suggest that iNKT cells participate in the regulation of host immune responses during facultative intracellular bacterial infection by controlling NK1.1 surface expression. These findings shed light not only on the unique role of iNKT cells in microbial infection, but also provide evidence for new aspects of the NK1.1 as a regulatory molecule on these cells.
Animals ; Humans ; Listeria Infections/*immunology ; Listeria monocytogenes/*immunology ; Natural Killer T-Cells/*immunology/*microbiology

Opportunistic bacteria in apical periodontitis (AP) may pose a risk for systemic dissemination. Mucosal-associated invariant T (MAIT) cells are innate-like T cells with a broad and potent antimicrobial activity important for gut mucosal integrity. It was recently shown that MAIT cells are present in the oral mucosal tissue, but the involvement of MAIT cells in AP is unknown. Here, comparison of surgically resected AP and gingival tissues demonstrated that AP tissues express significantly higher levels of Vα7.2-Jα33, Vα7.2-Jα20, Vα7.2-Jα12, Cα and tumour necrosis factor (TNF), interferon (IFN)-γ and interleukin (IL)-17A transcripts, resembling a MAIT cell signature. Moreover, in AP tissues the MR1-restricted MAIT cells positive for MR1-5-OP-RU tetramer staining appeared to be of similar levels as in peripheral blood but consisted mainly of CD4 subset. Unlike gingival tissues, the AP microbiome was quantitatively impacted by factors like fistula and high patient age and had a prominent riboflavin-expressing bacterial feature. When merged in an integrated view, the examined immune and microbiome data in the sparse partial least squares discriminant analysis could identify bacterial relative abundances that negatively correlated with Vα7.2-Jα33, Cα, and IL-17A transcript expressions in AP, implying that MAIT cells could play a role in the local defence at the oral tissue barrier. In conclusion, we describe the presence of MAIT cells at the oral site where translocation of oral microbiota could take place. These findings have implications for understanding the immune sensing of polymicrobial-related oral diseases.
Adult ; Aged ; Female ; Humans ; Immunity, Mucosal ; immunology ; Male ; Microbiota ; Middle Aged ; Mucosal-Associated Invariant T Cells ; Natural Killer T-Cells ; immunology ; Periapical Periodontitis ; microbiology ; surgery

OBJECTIVETo investigate the effect of microbial immune enteral nutrition composed of probiotics, deep sea fish oil, glutamine and nutrison on postoperative immune status, insulin resistance and infectious complication morbidity in patients with abdominal infection.

METHODSFrom September 2010 to April 2013 in Shandong Liaocheng City Hospital, 96 patients with upper gastrointestinal perforation were prospectively randomized into the treatment group (microbial immune enteral nutrition, n=48) and the control group(conventional enteral nutrition, n=48). Number of T cell subsets (CD3(+), CD4(+), CD8(+), CD4(+)/CD8(+)) and natural killer (NK) cell, procalcitonin (PCT), fasting blood glucose (FBG), fasting insulin (FINS), insulin resistance index (InHOMA-IR) calculated by the homeostasis model assessment(HOMA) were detected before operation and on days 3 and 7 after operation and compared between the two groups. The incidence of postoperative infectious complication was collected and compared as well.

RESULTSThere were no significant differences in immune indexes and insulin resistance-associated indexes between the two groups before operation and on the day 3 after operation(all P>0.05). On postoperative day 7, CD4(+), CD4(+)/CD8(+) and NK cells in treatment group were significantly higher than those in control group [(39.1±4.3)% vs. (30.1±5.7)%, P=0.043; 1.76±0.21 vs. 1.36±0.12, P=0.038; (19.3±4.8)% vs. (13.3±3.2)%, P=0.032], while FINS, lnHOMA-IR and PCT in treatment group were significantly lower than those in control group [(7.3±1.7) mU/L vs. (10.2±2.1) mU/L, P=0.041; 0.60±0.05 vs. 0.88±0.06, P=0.039; (0.12±0.07) μg/L vs. (0.35±0.12) μg/L, P=0.028]. Postoperative infectious complication morbidity was significantly lower in treatment group as compared to control group [18.8%(9/48) vs. 39.6%(19/48), P=0.025].

CONCLUSIONMicrobial immune enteral nutrition composed of probiotics, deep sea fish oil, glutamine and nutrison can improve the immune status, decrease the level of insulin resistance, and reduce the incidence of postoperative infectious complication for patients with abdominal infection due to upper gastrointestinal perforation.

Abdominal Injuries ; Calcitonin ; Calcitonin Gene-Related Peptide ; Enteral Nutrition ; Fish Oils ; Glutamine ; Humans ; Insulin Resistance ; Killer Cells, Natural ; Postoperative Complications ; immunology ; microbiology ; prevention & control ; Postoperative Period ; Probiotics ; Protein Precursors ; T-Lymphocyte Subsets

Animals ; Anti-Bacterial Agents ; administration & dosage ; Escherichia coli ; Female ; Galactosylceramides ; immunology ; Gastric Mucosa ; pathology ; Gastritis, Atrophic ; pathology ; Helicobacter Infections ; complications ; drug therapy ; Helicobacter pylori ; pathogenicity ; Humans ; Inflammation ; pathology ; Intestines ; microbiology ; Levofloxacin ; Lymphocyte Activation ; Male ; Natural Killer T-Cells ; microbiology ; Ofloxacin ; administration & dosage ; Sphingomonas ; Stomach ; pathology