SummaryInnate immunity is a semi-specific and widely distributed form of immunity, which represents the first line of defence against pathogens. This type of immunity is critical to maintain homeostasis and prevent microbe invasion, eliminating a great variety of pathogens and contributing with the activation of the adaptive immune response. The components of innate immunity include physical and chemical barriers, humoral and cell-mediated components, which are present in all jawed vertebrates. The understanding of innate defence mechanisms in non-mammalian vertebrates is the key to comprehend the general picture of vertebrate innate immunity and its evolutionary history. This is also essential for the identification of new molecules with applications in immunopharmacology and immunotherapy. In this review, we describe and discuss the main elements of vertebrate innate immunity, presenting core findings in this field and identifying areas that need further investigation.

No abstract

No abstract

HER-1 and HER-2 are tumor-associated antigens overexpressed in several epithelial tumors, and successfully targeted by therapeutic approaches against cancer. Vaccination with their recombinant extracellular domains has had encouraging results in the pre-clinical setting. As complex humoral responses targeting multiple epitopes within each antigen are the ultimate goal of such active immunotherapy strategies, molecular dissection of the mixture of antibody specificities is required. The current work exploits phage display of antigenic versions of HER-1 and HER-2 domains to accomplish domain-level epitope mapping. Recognition of domains I, III and IV of both antigens by antibodies of immunized mice was shown, indicating diverse responses covering a broad range of antigenic regions. The combination of phage display and site-directed mutagenesis allowed mutational screening of antigen surface, showing polyclonal antibodies’ recognition of mutated receptor escape variants known to arise in patients under the selective pressure of the anti-HER-1 antibody cetuximab. Phage-displayed HER domains have thus the potential to contribute to fine specificity characterization of humoral responses during future development of anti-cancer vaccines.

Subunit vaccines based on the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2, are among the most promising strategies to fight the COVID-19 pandemic. The detailed characterization of the protein primary structure by mass spectrometry (MS) is mandatory, as described in ICHQ6B guidelines. In this work, several recombinant RBD proteins produced in five expression systems were characterized using a non-conventional protocol known as in-solution buffer-free digestion (BFD). In a single ESI-MS spectrum, BFD allowed very high sequence coverage (≥ 99 %) and the detection of highly hydrophilic regions, including very short and hydrophilic peptides (2-8 amino acids), the His6-tagged C-terminal peptide carrying several post-translational modifications at Cys538 such as cysteinylation, glutathionylation, cyanilation, among others. The analysis using the conventional digestion protocol allowed lower sequence coverage (80-90 %) and did not detect peptides carrying some of the above-mentioned post-translational modifications. The two C-terminal peptides of a dimer [RBD(319-541)-(His)6]2 linked by an intermolecular disulfide bond (Cys538-Cys538) with twelve histidine residues were only detected by BFD. This protocol allows the detection of the four disulfide bonds present in the native RBD and the low-abundance scrambling variants, free cysteine residues, O-glycoforms and incomplete processing of the N-terminal end, if present. Artifacts that might be generated by the in-solution BFD protocol were also characterized. BFD can be easily implemented and we foresee that it can be also helpful to the characterization of mutated RBD.