The human immune response to bacterial blood stream infection (sepsis) and systemic viral infection are fairly well understood, but we lack details on the most early phases. Better knowledge of these events would be important for the prevention and treatment of severe bacterial or viral disease. From models of infection, we have data showing that bacteria replicate in a specific type of cells in the spleen from where the bacteria then seed to the blood to cause blood stream infection. In order to gain more relevant data for humans, we have developed a spleen perfusion model using pig organs. This model confirms our previous work and most importantly will now allow us to study these events in human organs. In order to move novel treatment strategies into human trials, we propose to test early events during infection using human spleens and the cells and tissues derived thereof. This research is expected to provide data on the relevance of the early events in bacterial and viral disease, in particular on the role of immune cells. The research includes work with human cells and tissue obtained from human spleens. In these settings, we will test pharmacological prevention and treatment of severe bacterial or viral infection (sepsis). The expected outcome of this work on human organs and tissue is expected to provide evidence that allows to move new treatment options into clinical trial. This study is a preclinical research project and does not involve any intervention on patients, but it involves human tissue. The source of the human splenic tissue for our research will be spleen tissue removed during radical surgery. The present application relates exclusively to the ethical approval for the use of spleen tissue removed during radical surgery and discarded. The utilisation of the spleen or splenic tissue for research purposes does not alter in any way the surgical procedures at any stage and importantly the research will involve only anonymity samples.