There is a need for techniques capable of identifying the antigenic epitopes targeted by polyclonal antibody responses during deliberate or natural immunization. than two days including the time required for antibody-mediated library selection. Moreover compared with traditional plaque selecting the new technology (named Phage-based Representation OF Immuno-Ligand Epitope Repertoire or PROFILER) provides superior resolution in epitope recognition. PROFILER seems ideally suited to streamline and guideline rational antigen design adjuvant selection and quality control of newly produced vaccines. Furthermore this method is also susceptible to Urapidil hydrochloride find important applications in additional fields covered by traditional quantitative serology. Intro Measuring the total concentration of antigen-specific serum antibodies is definitely a fundamental step in the analysis of infectious and autoimmune diseases and is Urapidil hydrochloride used to monitor the effectiveness of vaccination which is the most powerful tool to preserve human being health and to reduce the costs of medical care. However a purely quantitative analysis of serum antibodies is definitely a poor indication of the complexity of the antibody response which involves the activation of thousands of different B cell clones and the secretion of a wide variety of antibodies each directed against a different region of the immunizing antigen(s) . For reasons that are only partially understood the antibodies induced by any immunizing antigen are not equally directed against the various portions of the antigen molecule . Often within an antigen you will find areas that are strongly reactive with antibodies (i.e. immunodominant areas) flanked by domains that seem to be partially or completely overlooked by the immune system. Anti-microbial vaccination induces the production of a great variety of antigen-specific antibodies only a minority of which possesses the ability to protect against target infections  . In other words only particular antibodies – those directed against specific “hot places” of the antigen molecule – have immunoprotective activities. Therefore it has been proposed that pathogens sometimes adopt the strategy of incorporating in the context of their virulence factors immunodominant areas that function as “decoys” by preventing the immune system from focusing on the “sizzling places” . Although the exact nature and function of such “decoy” epitopes are still ill-defined it is well established that selective removal of immunodominant non-protective areas can boost Urapidil hydrochloride the ability of the antigen to protect against illness after immunization . In view of these considerations it would be helpful particularly in the course of preclinical studies and clinical tests involving vaccines to establish whether the immune response is definitely optimally targeted against the antigenic residues important for immune-mediated safety. To this end a method capable of providing a Urapidil hydrochloride detailed analysis of the good specificity of vaccine-induced antibody repertoires would be useful to lead rational antigen design and selection of appropriate adjuvants. Indeed the ability of particular adjuvants to broaden the antibody repertoire and to provide extended protection of antigen areas targeted by polyclonal reactions is becoming progressively obvious  . Moreover because the spectrum of antibody specificities varies with age and Rabbit Polyclonal to GIMAP2. physiology repertoire profiles may be useful to specifically tailor vaccine formulations for different age groups and for high-risk populations   . The recent development of high-throughput methods for repertoire data collection – from solitary cell mass spectroscopy and multicolor circulation cytometry to massively parallel sequencing of immunoglobulin transcripts – gives today an opportunity to analyze large samples of lymphocyte repertoires   . Although these methods provide extensive information concerning the diversity of clonotypes and immunoglobulin gene utilization they have limited usefulness by their nature in sampling the antibody repertoire in terms of epitope specificity. Libraries consisting of phage particles or cells expressing on their surface peptides of various lengths have been widely used in epitope mapping    . These techniques are however labor-intensive time consuming and can determine only a limited quantity of epitopes. We describe here a novel approach based on the combined use of phage-displayed antigen-specific libraries and massive parallel sequencing of the entire populace of affinity-selected phages. This.