Cellular Microbiology and Immunology

The program explores the cellular and molecular mechanisms that govern host-bacteria interactions, with a particular focus on pathogenic and commensal bacteria. Through an integrated approach combining microbiology, immunology, and -omics technologies, students will acquire an in-depth understanding of host-bacteria relationships, gaining insight into how these interactions contribute to the maintenance of health, promote disease development, or represent innovative targets for the development of novel therapeutic strategies.

The teaching activities are structured around the following topics:
· Fundamental principles of bacterial microbiology, ranging from bacterial taxonomy to the strategies employed by pathogenic bacteria to colonize the host, evade immune defenses, and cause disease. Major bacterial virulence factors, mechanisms of pathogenicity, and bacterial toxins will be examined, with particular emphasis on their impact on host cells.
· Mechanisms of recognition and molecular communication between bacteria and the innate immune system. The main functions of epithelial cells and antimicrobial peptides, as well as the activation and effector functions of phagocytes, including macrophages and neutrophils, are discussed. Cellular and molecular mechanisms of phagocytosis and neutrophil extracellular trap (NET) formation will be discussed. The role of Natural Killer cells and the complement system in host defense against pathogenic microorganisms will be examined, including their activation, cooperation, and protective functions. Innate Lymphoid Cells (ILCs), their classification, roles in mucosal immunity, and contribution to tissue homeostasis will also be addressed. Particular attention will be devoted to the immune evasion strategies employed by pathogenic microorganisms to escape innate immune responses. Antigen capture and presentation will be explored through the study of antigen-presenting cells (APCs), dendritic cells, and Major Histocompatibility Complex (MHC) class I and class II molecules. Mechanisms by which pathogenic microorganisms inhibit antigen presentation and modulate immunogenicity will also be discussed.
· Adaptive immunity: interactions between bacteria and T and B lymphocytes will be examined in depth. Mechanisms underlying the differentiation and activation of CD8+ and CD4+ T lymphocytes, their roles in host defense against intracellular and extracellular pathogens, and the processes driving the polarization of distinct T-helper cell subsets will be examined. Particular emphasis will be placed on the immunomodulatory strategies employed by pathogenic microorganisms to alter T-cell receptor (TCR) signaling, modulate B-cell activation, and influence the polarization of immune responses. The contribution of dysregulated host-microbe interactions to the development of autoimmune and chronic inflammatory diseases will also be discussed.
· Interactions between the human microbiota and the immune system: the composition, protective functions, and immunological roles of the microbiota will be analyzed, with particular focus on the mechanisms through which commensal bacteria contribute to the activation and regulation of innate and adaptive immune responses. Next-Generation Sequencing (NGS) technologies, omics approaches such as metagenomics and metatranscriptomics, third-generation sequencing technologies, and the major databases used in contemporary biomedical research will also be introduced. Host-microbiota interactions involved in the development of dysbiosis - including its definition, causes, and the mechanisms through which pathogenic microorganisms elude the protective and immunological functions of the microbiota - will also be analyzed. The impact of dysbiosis on chronic and immune-mediated diseases, as well as the microbiota-based therapeutic interventions, including prebiotics, probiotics, postbiotics, and engineered probiotics, will be examined with emphasis on their mechanisms of action and immunomodulatory potential. The microbiota as a target for personalized medicine will be addressed, highlighting emerging therapeutic opportunities for the management of dysbiosis-associated disorders. Particular attention will also be given to the Gut-Brain Axis and Gut-Lung Axis, focusing on the bidirectional communication between the intestinal microbiota, the central nervous system, and the respiratory tract, as well as the molecular and cellular mechanisms involved in neurodegenerative diseases.
· Interactions among the microbiota, pathogenic bacteria, and cancer: the mechanisms through which specific microorganisms contribute to tumor initiation and progression will be analyzed, including chronic inflammation, immune modulation, and remodeling of the tumor microenvironment. The role of the microbiota in regulating antitumor immune responses will also be examined, highlighting emerging therapeutic opportunities arising from the modulation of microbial communities.
· The principles of modern vaccinology, examining how advances in our understanding of host-microbe interactions have revolutionized vaccine development. The mechanisms through which antigens activate innate and adaptive immune responses will be discussed, together with the principles of classical vaccinology and reverse vaccinology, mRNA vaccine platforms, recombinant proteins, and the strategies leading to the induction of protective immunological memory.

The Laboratory activities will provide students with the opportunity to directly investigate host-bacteria interactions: using intestinal and pulmonary cell lines, students will evaluate the adhesion, invasion, and persistence capabilities of different bacterial strains while simultaneously assessing host inflammatory responses through immunological assays and the analysis of key mediators involved in host-pathogen communication.