oa Editorial [ Hot topic: Novel Vaccines and Adjuvants (Guest Editor: Luigi Buonaguro)]

The “mini hot topic” issue on Novel Vaccines and Adjuvants aims to present the most updated information on newly developed concepts in vaccines and adjuvants targeted to cancers as well as infectious diseases. Safety problems related to traditional attenuated or inactivated vaccines, together with broadening the vaccine concept to human diseases other than infectious (i.e. cancer), have considerably fuelled the vaccinology field in the search for the optimal safe and immunogenic vaccine model. In particular, the lack of an effective vaccine for HIV/AIDS is strongly pushing the entire vaccinology field to generate and validate new concepts, including novel strategies for antigen delivery and presentation, novel priming and boost protocols. Each of these strategies has a specific immunogenic property which can be used in standalone or combinatorial approaches, broadening the possibility of inducing specific or both arms of the immune response. Compared to the traditional vaccines, however, most of these novel approaches show a significantly low immunogenicity. This drawback, coupled to the need of inducing both arms of the adaptive immune response (humoral and cellular), is intensely driving the identification and design of novel adjuvants (including novel adjuvant's concepts) to significantly increase the number of available options besides the standard alum in human vaccines. In particular, the development of a completely novel class of adjuvants hitting the mucosal sites is of high relevance for the whole field. The recent acquisitions on the key role of innate immunity, and in particular of dendritic cells and their pathogen recognition receptors (including Toll-Like Receptors) in triggering and amplifying the adaptive immune response, have a multiplication effect on the number of “arrows” in the armamentarium of modern vaccinology. Dendritic cells can be specifically targeted, ex vivo or in vivo, to improve the antigen delivery and presentation to effector lymphocytes. Ligands of Toll-Like Receptors appears to be efficient adjuvants for significantly improving not only the immunogenicity of delivered antigens but also the specificity of the elicited immune response. All these different perspectives are greatly contributing to fill the pieces of our knowledge on mechanisms underlying the effective elicitation of protective immune responses by vaccines. This will enable the switch from the “empirical” to the “knowledge-based” age of the vaccinology which should lead to the development of even more successful vaccines for preventive as well as therapeutic intervention strategies. The papers included in the present Mini Hot Topic Issue on “Novel Vaccines and Adjuvants” will significantly contribute in describing some of the most significant aspects of this exciting and evolving field.