Influence of ethanol on TNF-alpha and IFN-gamma producing CD4+ and CD8+ T cells in surgical infectious mice model

Alkoholkranke haben ein erhöhtes Risiko, postoperativ an einer häufig durch Klebsiella pneumoniae (K. pneumoniae) verursachten Pneumonie zu erkranken. Die beiden Zytokine Tumornekrosefaktor-alpha (TNF-α) und Interferon-gamma (IFN-γ) sind bei der Abwehr von K. pneumoniae wichtig. Um die Auswirkung einer präoperativen Alkoholbehandlung auf die Immunantwort bei K. pneumoniae Pneumonie zu untersuchen, wurde ein operatives, infektiöses Mausmodell etabliert. 50 weibliche Balb/c Mäuse wurden acht Tage intraperitoneal mit Alkohol (3 mg/g Körpergewicht) oder Kochsalz behandelt, bevor am achten Tag eine mediane Laparotomie erfolgte. Am zweiten postoperativen Tag wurde die Hälfte der Tiere jeder Gruppe intranasal mit K. pneumoniae infiziert. 24 Stunden später wurden die Tiere getötet. Lunge und Leber wurden für die mikrobiologische und histologische Untersuchung sowie die Milz für die Zellisolation entnommen. Die Anzahl TNF-α und IFN-γ produzierender CD4+ und CD8+ T-Zellen der Milz wurde durchflusszytometrisch untersucht. Ergänzend erfolgten Gewichtskontrollen und die Erhebung eines klinischen Scores. Nach Infektion mit K. pneumoniae und Ethanolbehandlung zeigte sich eine signifikante Reduktion von TNF-α produzierenden CD4+ und CD8+ T-Zellen und IFN-γ produzierenden CD4+ Zellen. Die Anzahl IFN-γ produzierender CD8+ T-Zellen blieb unverändert. Histologisch war ein schwererer Verlauf der Klebsiellenpneumonie zu verzeichnen. Damit einher ging eine signifikante Gewichtsreduktion und ein schlechterer klinischer Score. Eine Ethanolbehandlung in diesem operativen, infektiösen Tiermodell führte nach Infektion mit K. pneumoniae zu einer Immunsuppression, die vermutlich ausgeprägtere histologische Lungenschäden und ein schlechteres Befinden der Tiere zur Folge hatte. Somit tragen T-Lymphozyten scheinbar durch ihr inadäquat sezerniertes Zytokinmuster zur Entstehung und Unterhaltung einer Klebsiellenpneumonie bei.The risk of bacterial pneumonia caused by Klebsiella pneumoniae (K. pneumoniae) is increased in alcoholic patients. Tumor necrosis factor alpha (TNF-α) and Interferon gamma (IFN-γ) are critical mediators of antibacterial host defence in Klebsiella pneumonia. A surgical infectious mice model was established in order to assess the impact of preoperative ethanol treatment on immune response during K. pneumoniae pneumonia. Fifty female Balb/c mice were treated with ethanol (3 mg/g body weight) or saline solution intraperitoneally for eight days. On the eighth day all mice underwent a median laparotomy. In half of each group K. pneumoniae was administered intranasally two days post surgery. Mice were killed twenty-four hours after infection. Lung and liver were extracted for microbiological and histological assessment as well as spleen for cell isolation. The number of TNF-α und IFN-γ producing splenic T cells were determined by FACS analysis. Additionally weights were registered and clinical appearance was assessed. The combination of infection with K. pneumoniae and ethanol treatment caused a significant decrease of TNF-α producing CD4+ and CD8+ T cells and IFN-γ producing CD4+ T cells. IFN-γ producing CD8+ T cells were not affected. Furthermore, the histological assessment showed a distinct deterioration of the pulmonary structure. Mice exhibited significant weight loss and a degraded clinical appearance. Ethanol treatment in this surgical infectious murine model led to immunosuppression after infection with K. pneumoniae. This immunosupression probably aggravated lung tissue damage as well as worsened the state of health. The inadequate cytokine pattern of T cells apparently contributes to the development of severe pneumonia

Differential T cell response against BK virus regulatory and structural antigens: A viral dynamics modelling approach.

BK virus (BKV) associated nephropathy affects 1-10% of kidney transplant recipients, leading to graft failure in about 50% of cases. Immune responses against different BKV antigens have been shown to have a prognostic value for disease development. Data currently suggest that the structural antigens and regulatory antigens of BKV might each trigger a different mode of action of the immune response. To study the influence of different modes of action of the cellular immune response on BKV clearance dynamics, we have analysed the kinetics of BKV plasma load and anti-BKV T cell response (Elispot) in six patients with BKV associated nephropathy using ODE modelling. The results show that only a small number of hypotheses on the mode of action are compatible with the empirical data. The hypothesis with the highest empirical support is that structural antigens trigger blocking of virus production from infected cells, whereas regulatory antigens trigger an acceleration of death of infected cells. These differential modes of action could be important for our understanding of BKV resolution, as according to the hypothesis, only regulatory antigens would trigger a fast and continuous clearance of the viral load. Other hypotheses showed a lower degree of empirical support, but could potentially explain the clearing mechanisms of individual patients. Our results highlight the heterogeneity of the dynamics, including the delay between immune response against structural versus regulatory antigens, and its relevance for BKV clearance. Our modelling approach is the first that studies the process of BKV clearance by bringing together viral and immune kinetics and can provide a framework for personalised hypotheses generation on the interrelations between cellular immunity and viral dynamics

Results of the model fitting for the hypotheses on dominant immune modes of action.

<p>Results of the model fitting for the hypotheses on dominant immune modes of action.</p

Fitting of immune response data.

<p>The calculated values for the immune response (lines) are plotted against the observed values (plus sign). Note the difference of time scales between the rows.</p

Immune function curve parameters.

<p>Immune function curve parameters.</p

Parameter for the viral load clearance model under hypothesis VPε-sLTμ.

<p>Parameter for the viral load clearance model under hypothesis VPε-sLTμ.</p

Schematic representation of the ODE model.

<p>Healthy cells produce other healthy cells (rate proportional to <i>g</i>) and die at rate <i>d</i>. The virus triggers the conversion of healthy cells into infected cells (rate <i>β</i>). Infected cells die at rate <i>d·k</i> and produce the virus at rate <i>p</i>, which is cleared at rate <i>c</i>. The immune system can intervene through three different mechanisms: blocking virus production (<i>ε(t)</i>), enhancing infected cell death (<i>μ(t)</i>) and blocking infection (<i>ν(t)</i>).</p

Modelled time course of BKV viral load clearance for hypothesis VPε-sLTμ.

<p>The results of the model (Eqs <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1005998#pcbi.1005998.e005" target="_blank">3</a>–<a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1005998#pcbi.1005998.e014" target="_blank">5</a>) under hypothesis VPε-sLTμ (<a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1005998#pcbi.1005998.s002" target="_blank">S2 Table</a>) using the parameters in <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1005998#pcbi.1005998.t004" target="_blank">Table 4</a> are plotted: viral load (<i>V</i>(t)) is shown as a black line, the immune responses virus production blockage (<i>ε</i>(t)) and accelerated killing of infected cells (<i>μ</i>(t)) are shown in green and red, respectively. Observed viral load values are shown as black plus signs. Please note the difference of time scales between the rows.</p