Vaccination protocols based on targeting of the idiotype expressed on malignant B cells have so far provided encouraging results in clinical trials. The essential requirement to induce an immune response is the inclusion of carriers to overcome T-cell tolerance. Chemical cross-linking of idiotypic protein is so far the method of choice to induce protective responses in human studies. Meanwhile, a flurry of alternative strategies to simplify vaccine production is being tested in murine model. Thanks to the advance in antibody engineering the two relevant antigenic domains of the lymphoma immunoglobulin can be assembled into an appropriate format, genetically linked to molecules that act as immunological adjuvants and directly delivered as plasmid DNA. Upon immunization, rejection of tumor cells may depend on cellular or humoral mechanisms, whose relative importance has not been entirely estimated. We have recently analyzed the specificity of anti-idiotypic antibodies induced by DNA vaccination and characterised the elements contributing to optimal anti-idiotypic responses.
The rotavirus (RV) VP4 spike protrudes as a trimeric structure from the five-fold axes of the virion triple-layer. Infectious RV particles need to be proteolytically cleaved in VP4 into two subunits, VP8* and VP5*, constituting both the distal part and central body of the virus spike. Modification of VP4 has been challenging as it is involved in biological processes such as the interaction with sialic acid and integrins, cell tropism and hemagglutinin activity. Using RV reverse genetics, four loops in the lectin domain of the VP8* subunit were engineered independently to harbor a small biotin acceptor peptide (BAP) tag and then tested for their ability to rescue virus. Only a single recombinant virus, rRV/VP4-BAP, harboring VP4 with a modified loop at position K145-G150 was rescued. This rRV/VP4-BAP internalizes, replicates, and generates virus progeny, demonstrating that the VP4 spike of RV particles can be genetically manipulated by the incorporation of at least 15 exogenous amino acids. VP4-BAP had a similar distribution as VP4 in infected cells by localizing in the cytoskeleton and surrounding viroplasms. However, compared to wild-type RV, rRV/VP4-BAP featured a reduced replication fitness and impaired viroplasm stability. Upon treatment with 1,6-hexanediol, a drug disrupting liquid-liquid phase-separated condensates, the kinetic of rRV/VP4-BAP viroplasm recovery was delayed, and their size and numbers reduced when compared to viroplasms of wild type RV. Moreover, siRNA silencing of VP4 expression in RV strain SA11 showed similar recovery patterns as rRV/VP4-BAP, revealing a novel function of VP4 in viroplasm stability.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.