The 2011 Nobel Prize for Medicine was awarded to Bruce Beutler of the United States, Jules Hoffman of Luxembourg and Ralph Steinman of Canada for their groundbreaking research that changed the existing understanding of the immune system, revealing the key principles of its activation. The immune system enables the body to defend itself with the release of antibodies and killer cells that respond to viruses and bacteria. Their research opens the path for the development of new drugs and protection against immunodeficiency, as well as the development of preventive measures and treatments of infections, cancer and inflammatory diseases.

The basic functions of the immune system are to recognize the exceptional diversity of pathogens, activate effector mechanisms for killing them and provide maximum protection from tissue damage. Effector activation mechanisms of innate and acquired immunity precede the receptor recognition of various structural components of microorganisms. The original structural components of pathogens (structural “templates”) recognize Toll-like receptors (TLR) and NOD-like receptors (NLR). (The aforementioned families of receptors are expressed primarily at the surface and in the cytoplasm of immune cells of innate immunity, such as neutrophils, macrophages and dendritic cells. The interaction between receptors and target structures activates the immune cells to create various cytokines and other mediators of innate immunity, with the goal of eliminating the pathogens. In addition to effector cells of innate immunity, macrophages and dendritic cells are also presenter cells that express HLA molecules and costimulatory molecules that allow them to present very specific structures (antigens) of microbial lymphocytes T and B and the activation of effector mechanisms of acquired immunity. Unlike the receptors of innate immunity, antigen-specific T-cell receptors (TCR) and B lymphocyte receptors (BCR) are highly specific to the structure presented in the HLA Class I and II molecules. In the microenvironment, cytokines of innate immunity are important in the activation of acquired cellular and humoral immunity, which in addition to their specificity are characterized by their ability to recognize antigens. Excessive activation of the receptors of innate immunity can lead to autoinflammatory diseases or the activation of autoimmune diseases. By contrast, dendritic cells, as the most effective presenter cells in the activation of acquired immunity, are used as vaccines in the treatment of some malignancies.

Professor Branko Malenica is a senior scientist at the University Hospital Center Zagreb and head of the Functional Testing Laboratory, Division of Immunology, Clinical Institute of Laboratory Diagnostics. He was born in Split in 1947, and graduated from the School of Medicine, University of Zagreb, in 1970. From 1972 to 1974, he pursued postgraduate studies in experimental biology at the University of Zagreb and earned a doctorate at the same institution in 1978. From 1978 to 1993, he held the positions of research associate, senior research associate and senior scientist at the Central Institute for Tumors and Allied Diseases in Zagreb. From 1983 to 1985, he was a visiting professor at the Max Planck Institute in Tübingen, Germany, in the Immunogenetics Laboratory under Prof. Jan Klein. Since 1993, he has been the head of the Functional Testing Laboratory, Division of Immunology, University Hospital Center Zagreb. His scientific interests are immunopathogenesis and the immunodiagnostics of autoimmune and malignant diseases. Professor Malenica is a professor of oncology and immunology at the Faculty of Science, Faculty of Pharmacy and Biochemistry, and the School of Medicine at the University of Zagreb. He has published 105 papers (42 in CC) in foreign and domestic journals and books.