Killer T cells in influenza

Antigen-specific CD8+ T cells play an important role in virus clearance. Here we review the current understanding of influenza virus-specific CD8+ T cell immunity in experimental mouse models and humans. The characteristics and nature of CD8+ T cell killing are discussed, as is the selection and maintenance of the influenza-specific effector and memory repertoires. Consideration is given to vaccine strategies and to the effects of ageing. Understanding the complexities of CD8+ T cell mediated immunity and memory has the potential for improving vaccine design, particularly to combat pandemics caused by newly emerging influenza viruses.

The honeymoon killer : plea bargaining and intimate femicide : a response to Watson

In October 2003, US citizen Christina Thomas died while scuba diving on Queensland’s Great Barrier Reef. Following over five years of delays, her husband David Watson accepted a plea bargain to which he pleaded guilty to manslaughter on the basis of criminal negligence. Watson was initially sentenced to four and a half years imprisonment, suspended after 12 months, however this was later increased on appeal to suspension after 18 months. Using Watson as a framework for analysis, this article examines some of the limitations of an inefficient justice system, with a particular focus on the private nature of the plea bargaining process, and the potentially favourable representations and sentencing of men who kill a female intimate partner. The authors argue that the need to respond to court inefficiency and under-resourcing in the criminal courts creates pressures that can result in a desire for increased efficiency being prioritised above other justice concerns, and this allows for existing flaws within the operation of the criminal justice system to be exacerbated, and excused.

Enhanced cytotoxic function of natural killer and natural killer T-like cells associated with decreased CD94 (Kp43) in the chronic obstructive pulmonary disease airway

Background and objective: Natural killer (NK) and natural killer T (NKT)-like cells represent a small but important proportion of effector lymphocytes that we have previously shown to be major sources of pro-inflammatory cytokines and granzymes. We hypothesized that these cells would be increased in the airway in chronic obstructive pulmonary disease (COPD), accompanied by reduced expression of the inhibitory receptor CD94 (Kp43) and increased expression of cytotoxic mediators granzyme B and perforin.
Methods: We measured NK and NKT-like cells and their expression of CD94 in the blood of COPD patients (n = 71; 30 current and 41 ex-smokers), smokers (16) and healthy controls (25), and bronchoalveolar lavage fluid (BALF) from a cohort of subjects (19 controls, 12 smokers, 33 COPD). Activation was assessed by measuring CD69 in blood and the cytotoxic potential of NK cells by measuring granzymes A and B, and using a cytotoxicity assay in blood and BALF.
Results: In blood in COPD, there were no significant changes in the proportion of NK or NKT-like cells or expression of granzyme A or NK cytotoxic potential versus controls. There was, however, increased expression of granzyme B and decreased expression of CD94 by both cell types versus controls. The proportion of NK and NKT-like cells were increased in BALF in COPD, associated with increased NK cytotoxicity, increased expression of granzyme B and decreased expression of the inhibitory receptor CD94 by both cell types.
Conclusions: Treatment strategies that target NK and NKT-like cells, their cytotoxicity and production of inflammatory mediators in the airway may improve COPD morbidity.

Leukocyte numbers and function in subjects eating n-3 enriched foods: selective depression of natural killer cell levels

Introduction : While consumption of omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) has been recommended for those at risk of inflammatory disease such as rheumatoid arthritis, the mechanism of their anti-inflammatory effect remains to be clearly defined, particularly in relation to the dose and type of n-3 LCPUFA. The objective of this study was to determine whether varying the levels of n-3 LCPUFA in erythrocyte membrane lipids, following dietary supplementation, is associated with altered numbers and function of circulating leukocytes conducive to protection against inflammation. Methods : In a double-blind and placebo-controlled study, 44 healthy subjects aged 23 to 63 years consumed either standard or n-3 LCPUFA-enriched versions of typical processed foods, the latter allowing a target daily consumption of 1 gram n-3 LCPUFA. After six months, peripheral blood leukocyte and subpopulation proportions and numbers were assessed by flow cytometry. Leukocytes were also examined for lymphoproliferation and cytokine production, neutrophil chemotaxis, chemokinesis, bactericidal, adherence and iodination activity. Erythrocytes were analyzed for fatty-acid content. Results : Erythrocyte n-3 LCPUFA levels were higher and absolute leukocyte and lymphocyte numbers were lower in subjects consuming n-3 enriched foods than in controls. There were no changes in the number of neutrophils, monocytes, T cells (CD3+), T-cell subsets (CD4+, CD8+) and B cells (CD19+). However, natural killer (NK) (CD3-CD16+CD56+) cell numbers were lower in n-3 supplemented subjects than in controls and were inversely related to the amount of eicosapentaenoic acid or docosahexaenoic acid in erythrocytes. No significant correlations were found with respect to lymphocyte lymphoproliferation and production of IFN-γ and IL-2, but lymphotoxin production was higher with greater n-3 LCPUFA membrane content. Similarly, neutrophil chemotaxis, chemokinesis, bactericidal activity and adherence did not vary with changes in erythrocyte n-3 LCPUFA levels, but the iodination reaction was reduced with higher n-3 LCPUFA content. Conclusion : The data show that regular long-term consumption of n-3 enriched foods leads to lower numbers of NK cells and neutrophil iodination activity but higher lymphotoxin production by lymphocytes. These changes are consistent with decreased inflammatory reaction and tissue damage seen in patients with inflammatory disorders receiving n-3 LCPUFA supplementation.

Identification of natural killer cell receptor genes in the genome of the marsupial Tasmanian devil (Sarcophilus harrisii)

Within the mammalian immune system, natural killer (NK) cells contribute to the first line of defence against infectious agents and tumours. Their activity is regulated, in part, by cell surface NK cell receptors. NK receptors can be divided into two unrelated, but functionally analogous superfamilies based on the structure of their extracellular ligand-binding domains. Receptors belonging to the C-type lectin superfamily are predominantly encoded in the natural killer complex (NKC), while receptors belonging to the immunoglobulin superfamily are predominantly encoded in the leukocyte receptor complex (LRC). Natural killer cell receptors are emerging as a rapidly evolving gene family which can display significant intra- and interspecific variation. To date, most studies have focused on eutherian mammals, with significantly less known about the evolution of these receptors in marsupials. Here, we describe the identification of 43 immunoglobulin domain-containing LRC genes in the genome of the Tasmanian devil (Sarcophilus harrisii), the largest remaining marsupial carnivore and only the second marsupial species to be studied. We also identify orthologs of NKC genesKLRK1, CD69, CLEC4E, CLEC1B, CLEC1A and an ortholog of an opossum NKC receptor. Characterisation of these regions in a second, distantly related marsupial provides new insights into the dynamic evolutionary histories of these receptors in mammals. Understanding the functional role of these genes is also important for the development of therapeutic agents against Devil Facial Tumour Disease, a contagious cancer that threatens the Tasmanian devil with extinction.

Valor prognóstico de células TCD8+ E natural killer em carcinoma epidermóide oral e orofaringeano tratado com radioterapia e quimioterapia

The most common malignant neoplasm of the oral cavity and oropharynx are squamous cell carcinoma. Injuries to the same stage and subjected to the same treatment protocol have sometimes different evolutionary courses. The scope of this study was to investigate, through a retrospective cohort, associations between the number of CD8 + T cells and natural killer, identified immunohistochemically in the inflammatory infiltrate in a series of cases of oral squamous cell carcinoma and orofaringeano, and the level of tumor response to radiotherapy and chemotherapy, overall survival and relapse-free survival of patients. We identified 54 patients with unresectable disease were treated exclusively with radiotherapy and chemotherapy. The median follow-up was 22 months. The sample was characterized by the predominance of male subjects, median age 60 years, all were smokers. The most frequent site was the tongue and 81.5% were in stage IV. Patients with disease in the oral cavity had a worse response to treatment (p = 0.006), worse relapse-free survival (p = 0.007), worse overall survival (p = 0.007). The advanced T stage was shown a negative prognostic factor (p= 0.006) for the clinical treatment response made. Immunohistochemistry was performed to select CD8 + cells (anti-CD8) and NK cells (anti-CD57). Lymphocytes positive and negative markings were counted using the program ImageJ ®. Two groups were created for each marking evaluated: Group I patients with more than 50% cells positive, Group II: less than 50% of labeled cells. For CD8 + cells detected in 38 (70.3%) of Group I were CD8 + and 16 (29.7%) Group II CD8 +. For NK cells, 26 (48.15%) Group I NK and 28 (51.85%) Group II NK. Regarding the clinical response to treatment, we observed that 39% of patients achieved a complete response and 25.9% remained without recurrence at the end of follow-up. These results were better in Group I CD8 + (p = 0.2). Identified that 72.2% of patients progressed to death, this finding had no association with the immunohistochemical data. There was no statistically significant differences between the number of CD8 + and NK cells and the ability of tumor response to radiotherapy and chemotherapy, or with overall survival and relapse-free survival of patients. However, especially in relation to a learned response, we found that this group of patients with advanced disease have a low count of CD8 + T cells active. Believing in the role that the immune response plays in the local fight against neoplastic cells, however, our results do not support the use of quantitative analysis of CD8 + T cells and NK cells as a prognostic factors for oral squamous cell carcinoma and oropharynx

Natural killer activity in a medium-term multi-organ bioassay for carcinogenesis

Natural killer (NK) cell activity was evaluated after the initiation and promotion steps in a medium-term multi-organ bioassay for carcinogenesis. NK cell activity was assessed in vitro by Cr-51 release assay at the 4th and 30th weeks of the experiment. Male Wistar rats were sequentially initiated with N-diethylnitrosamine (DEN i.p.), N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN drinking water), N-methyl-N-nitrosourea (MNU i.p.), dihydroxy-di-N-propylnitrosamine (DHPN drinking water) and N,N'-dimethylhydrazine (DMH s.c.) at subcarcinogenic doses for 4 weeks (DMBDD initiation). One group was evaluated at the 4th week and the other was maintained without any further treatment until the 30th week. Two initiated groups were exposed through the diet to 2-acetylaminofluorene (2-AAF) or phenobarbital (PB), from the 6th until the 30th week, Five additional groups were studied to evaluate the effects of each initiator on NK activity. All groups submitted to initiation only, initiation plus promotion, or promotion only, developed significantly more preneoplastic lesions than the untreated control group. The main target organs for tumor development in the initiated animals n ere the liver and the colon, irrespective of treatment with 2-AAF or PB. NK cell activity was not affected bal exposure to genotoxic carcinogens after initiation, at the 4th week. Treatments only with PB or 2-AAF did not change NK cell activity, However, decreased NK cell activity was registered in the group only initiated with DMBDD and in the group given DMBDD+2-AAF. This late depression of NK cell activity at the 30th week could be related to the production of suppressing molecules by the tumor cells.

Infiltrating CD8(+) T lymphocytes, natural killer cells, and expression of IL-10 and TGF-beta 1 in chemically induced neoplasms in male Wistar rats

The present study aimed to estimate the number of CD8(+) T and natural killer (NK) infiltrating cells and the expression of interleukin-10 (IL-10) and transforming growth factor beta 1 (TGF-beta1) in chemically induced neoplasms in an initiation-promotion bioassay for carcinogenesis. Male Wistar rats were treated with N-nitrosodiethylamine, N-methyl-N-nitrosourea, N-butyl-N-(4-hydroxybutyl) nitrosamine, dihydroxy-di-N-propylnitrosamine, and 1,2-dimethylhydrazine for 4 weeks. Two groups were subsequently exposed through diet to phenobarbital (0.05%) or 2-acetylaminofluorene (0.01%) for 25 weeks. An untreated group was used as a control. Immune cells and cytokines were immunohistochemically evaluated in neoplasms and in surrounding normal tissues at the liver, kidneys, lung, and small and large intestines. When compared to the respective normal tissues, an increased number of NK cells was verified infiltrating the colon, lung, and kidney neoplasms, while the number of CD8+ T cells decreased in the intestine and lung neoplasms. Expression of IL-10 was found mainly in kidney tumors. TGF-beta1 was expressed mainly in the liver and kidneys tumors. The results indicate that the differential occurrence of immune cells between neoplastic and normal tissues could be dependent upon tumor microenvironment.

Occurrence of coagulase-positive Staphylococcus in various food products commercialized in Botucatu, SP, Brazil and detection of toxins from food and isolated strains

The aim of this work was to assess the microbiological quality of commercialized desserts, sandwiches and finger food in Botucatu, SP, for human consumption. A total of 172 food samples were analyzed for fecal coliforms and coagulase-positive Staphylococcus and 69 (40.1%) were in disagreement with the standards established by Decree No. 12 (Brazilian Food Sanitation Standard, 2001). Coagulase-positive Staplylococcus was isolated from 26 (15.1%) samples. Toxins were not isolated directly from foods but 27 (54%) coagulase-positive Staphylococcus strains were enterotoxigenic, and toxin type C was the most frequently detected. These results suggest that these products may act as an important vehicle of transmission for well-established pathogens. (c) 2006 Elsevier Ltd. All rights reserved.

Enhanced natural killer activity and production of pro-inflammatory cytokines in mice selected for high acute inflammatory response (AIRmax)

Strains of mice with maximal and minimal acute inflammatory responsiveness (AIRmax and AIRmin, respectively) were developed through selective breeding based on their high- or low-acute inflammatory responsiveness. Previous reports have shown that AIRmax mice are more resistant to the development of a variety of tumours than AIRmin mice, including spontaneous metastasis of murine melanoma. Natural killer activity is involved in immunosurveillance against tumour development, so we analysed the number and activity of natural killer cells (CD49b(+)), T-lymphocyte subsets and in vitro cytokine production by spleen cells of normal AIRmax and AIRmin mice. Analysis of lymphocyte subsets by flow cytometry showed that AIRmax mice had a higher relative number of CD49b(+) cells than AIRmin mice, as well as cytolytic activity against Yac.1 target cells. The number of CD3(+) CD8(+) cells was also higher in AIRmax mice. These findings were associated with the ability of spleen cells from AIRmax mice in vitro to produce higher levels of the pro-inflammatory cytokines tumour necrosis factor-alpha, interleukin-12p40 and interferon-gamma but not the anti-inflammatory interleukin-10. Taken together, our data suggest that the selective breeding to achieve the AIRmax and AIRmin strains was able to polarize the genes associated with cytotoxic activity, which can be responsible for the antitumour resistance observed in AIRmax mice.

Natural killer activity in mice infected with rabies virus and submitted to P-acnes (Propionibacterium acnes) as immunomodulator

The natural killer (NK) activity and lethality were evaluated in swiss mice experimentally infected with street rabies virus and submitted to immunomodulation by P. acnes (formerly Corynebacterium parvum). The infected animals were sacrificed at different times and spleen non-adherent cells were obtained through ficoll-hypaque gradient and depletion of glass-adherent cells. Immunosuppression was observed in rabies virus infected mice correlated with lower NK activity in clinically ill animals. Higher NK activity and percentual of survival were observed in the group submitted to P. acnes. The increased survival correlated with higher NK activity induced by P. acnes suggests a protective role of this natural barrier against rabies virus infection in mice. (C) 2000 Elsevier B.V. Ltd. All rights reserved.

Neutralization of snake venom phospholipase A(2) toxins by aqueous extract of Casearia sylvestris (Flacourtiaceae) in mouse neuromuscular preparation

Aqueous extract of Casearia sylvestris (Flacourtiaceae) has been shown to inhibit enzymatic and biological properties of some Bothrops and Crotalus venoms and their purified phospholipase A(2) (PLA(2)) toxins. In this work we evaluated the influence of C sylvestris aqueous extract upon neuromuscular blocking and muscle damaging activities of some PLA(2)S (crotoxin from C. durissus terrificus, bothropstoxin-I from B.jararacussu, piratoxin-I from B. pirajai and myotoxin-II from B. moojeni) in mouse phrenic-diaphragm preparations. Crotoxin (0.5 mu M) and all other PLA2 toxins (1.0 mu M) induced irreversible and time-dependent blockade of twitches. Except for crotoxin, all PLA2 toxins induced significant muscle damage indices, assessed by microscopic analysis. Preincubation of bothropstoxin-I, piratoxin-I or myotoxin-II with C. sylvestris extract (1:5 (w/w), 30 min, 37 degrees C significantly prevented the neuromuscular blockade of preparations exposed to the mixtures for 90 min; the extent of protection ranged from 93% to 97%. The vegetal extract also neutralized the muscle damage (protection of 80-95%). Higher concentration of the C. sylvestris extract (1: 10, w/w) was necessary to neutralize by 90% the neuromuscular blockade induced by crotoxin. These findings expanded the spectrum of C. sylvestris antivenom activities, evidencing that it may be a good source of potentially useful PLA2 inhibitors. (c) 2007 Elsevier B.V.. All rights reserved.