Aberrant Her2/neu expression is associated with the development of epithelial-derived human carcinomas and for this reason it is considered a good target for immunologic intervention. To define methods to circumvent immunologic tolerance and to elicit immunity against the Her2/neu tumor-associated antigen in a suitable animal model, we have isolated the cDNA encoding the rhesus monkey homolog of human Her2/neu (RhErbB2) to construct DNA plasmids and adenoviral vectors for the development of a cancer vaccine against this protein. To further increase the immunogenic potency of these vectors, a synthetic codon-optimized RhErbB2 cDNA (RhErbB2OPT) was constructed and characterized. Genetic vaccination of rhesus monkeys was effective in inducing a response against RhErbB2 in immunized animals; importantly, the elicited immunity was associated with natural RhErbB2 polymorphisms, thus distinguishing responses against “self ” and “nonself ” epitopes. In particular, the postpriming response recognized mainly nonself epitopes whereas the boosted response cross-reacted with self epitopes. Our findings are particularly relevant in the investigation of the impact of TAA polymorphisms on the efficacy of a cancer vaccine strategy.

The COVID-19 pandemic, once a global crisis, is now largely under control, a testament to the extraordinary global efforts involving vaccination and public health measures. However, the relentless evolution of SARS-CoV-2, leading to the emergence of new variants, continues to underscore the importance of remaining vigilant and adaptable. Monoclonal antibodies (mAbs) have stood out as a powerful and immediate therapeutic response to COVID-19. Despite the success of mAbs, the evolution of SARS-CoV-2 continues to pose challenges and the available antibodies are no longer effective. New variants require the ongoing development of effective antibodies. In the present study, we describe the generation and characterization of neutralizing mAbs against the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein by combining plasmid DNA and recombinant protein vaccination. By integrating genetic immunization for rapid antibody production and the potent immune stimulation enabled by protein vaccination, we produced a rich pool of antibodies, each with unique binding and neutralizing specificities, tested with the ELISA, BLI and FACS assays and the pseudovirus assay, respectively. Here, we present a panel of mAbs effective against the SARS-CoV-2 variants up to Omicron BA.1 and BA.5, with the flexibility to target emerging variants. This approach ensures the preparedness principle is in place to address SARS-CoV-2 actual and future infections.

Background/Objectives: The ErbB protein family plays a critical role in the progression of various solid tumors, and HER3 has been implicated in resistance mechanisms to multiple cancer therapies due to its ability to form heterodimers with other ErbB receptors, thereby activating pathways that promote tumor growth and survival. This study aimed to generate and characterize humanized monoclonal antibodies against HER3 to inhibit its function and evaluate their potential as therapeutic agents. Methods: Murine monoclonal antibodies TK-A3 and TK-A4 were humanized and tested for binding to ErbB3 and competition with neuregulin-1β (NRG). Specificity was assessed by ELISA, and epitope identified by X-ray crystallography. Downstream signaling was analyzed by western blot for phosphorylated ErbB3, Akt, and MAPK. Antitumor activity was evaluated in vitro and in a pancreatic cancer xenograft model. A toxicology study was also conducted. Results: TK-hu A3 and TK-hu A4 bound specifically to ErbB3 without cross-reactivity to other ErbB receptors. The ErbB3-TK-hu A3 Fab structure revealed the binding epitope. Both antibodies competed with NRG, inhibiting ErbB3, Akt, and MAPK phosphorylation in a dose-dependent manner. They suppressed cancer cell survival in vitro, and TK-hu A3 significantly delayed tumor growth in vivo. The toxicology study indicated good tolerability. Conclusions: TK-hu A3 emerged as the lead candidate, showing specific HER3 targeting, strong pathway inhibition, and antitumor efficacy in vivo. Beyond standalone use, it could support novel strategies such as T-cell engagers, ADCs, CAR-T, and bispecific antibodies. These findings highlight TK-hu A3 as a promising therapy for HER3-positive, treatment-resistant cancers, meriting further development.

Background Coronavirus disease 2019 (COVID-19) emerged in late December 2019 and was declared pandemic in March 2020 by the World Health Organization, causing clinically acute respiratory manifestations and corresponding symptoms, pathological inflammation and multi-organ dysfunctions. The total commitment of the scientific community to develop therapeutics to deal with this global emergency in the shortest possible period was unprecedented. In a very short time, several vaccines were approved by the EMA (European Medicines Agency) and the FDA (Food and Drug Administration). Despite this, it is conceivable that COVID-19 will continue to spread globally through evolving variants in more or less cyclic waves. With these perspectives, it is essential to quickly develop additional therapeutic tools to deal with the next wave of infection. Methods In the present study we describe the development and characterization of neutralizing mouse monoclonal antibodies (mAbs) against the receptor binding domain (RBD) of the SARS-CoV-2 Spike (S) protein. Results The mAbs identified are able to specifically detect the RBD of SARS-CoV-2 Spike protein in all tested applications, including enzyme-linked immunosorbent assay (ELISA), flow cytometry (FACS) and bio-layer interferometry. In addition, we show that these mAbs efficiently block entry of both SARS-CoV-2 pseudoparticles carrying the spike protein of the original SARS-CoV-2 strain and a broad set of variants of concern (VOC). Conclusions Here we report a panel of monoclonal antibodies that target RBD and inhibit SARS-CoV-2 variants infection and enable the isolation of novel therapeutic tools to neutralize SARS-CoV-2 virus