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Introducción: Las estrategias vacunales para potenciar respuestas de linfocitos T CD8+ citotóxicos (CTL) constituyen un reto debido a la necesidad de favorecer la presentación cruzada de antígenos (Ag) exógenos por las células presentadoras de antígenos (APC). Con este propósito se han empleado liposomas que encapsulan proteínas formadoras de poros (PFP) de origen bacteriano. Objetivo: explorar la habilidad de liposomas que co-encapsulan el Ag ovoalbúmina (OVA) y sticholysina II (StII), una PFP producida por Stichodactyla helianthus, de inducir una respuesta de CTL, funcional en un modelo tumoral. Métodos: Liposomas que co-encapsulaban OVA y StII se prepararon mediante deshidratación-rehidratación (Lp/OVA/StII). Se evaluó la respuesta de CTL, así como la actividad antitumoral en un escenario preventivo. La capacidad de StII de estimular la maduración de las células dendríticas (DC) in vitro fue también explorada. Resultados: Lp/OVA/StII potenció la respuesta de CTL específica a OVA y una actividad antitumoral en ratones retados con el tumor E.G7-OVA. StII indujo la maduración de las DC in vitro, lo que resultó dependiente del receptor tipo Toll 4 (TLR4), con una contribución en la respuesta de CTL inducida por la formulación liposomal in vivo. Lp/OVA/StII favoreció in vitro la presentación cruzada de OVA y la activación de células T CD8+ por macrófagos, pero no por DC. Estos resultados son la primera evidencia de que StII encapsulada en liposomas funciona como una plataforma vacunal para inducir una respuesta de CTL robusta, con una contribución que va más allá de su habilidad de formar poros en membranas.

Actinoporins (APs) are soluble pore-forming proteins secreted by sea anemones that experience conformational changes originating in pores in the membranes that can lead to cell death. The processes involved in the binding and pore-formation of members of this protein family have been deeply examined in recent years; however, the intracellular responses to APs are only beginning to be understood. Unlike pore formers of bacterial origin, whose intracellular impact has been studied in more detail, currently, we only have knowledge of a few poorly integrated elements of the APs’ intracellular action. In this review, we present and discuss an updated landscape of the studies aimed at understanding the intracellular pathways triggered in response to APs attack with particular reference to sticholysin II, the most active isoform produced by the Caribbean Sea anemone Stichodactyla helianthus. To achieve this, we first describe the major alterations these cytolysins elicit on simpler cells, such as non-nucleated mammalian erythrocytes, and then onto more complex eukaryotic cells, including tumor cells. This understanding has provided the basis for the development of novel applications of sticholysins such as the construction of immunotoxins directed against undesirable cells, such as tumor cells, and the design of a cancer vaccine platform. These are among the most interesting potential uses for the members of this toxin family that have been carried out in our laboratory.

Rhenium (Re) is widely used in the diagnosis and treatment of cancer due to its unique physical and chemical properties. Re has more valence electrons in its outer shell, allowing it to exist in a variety of oxidation states and to form different geometric configurations with many different ligands. The luminescence properties, lipophilicity, and cytotoxicity of complexes can be adjusted by changing the ligand of Re. This article mainly reviews the development of radionuclide 188Re in radiotherapy and some innovative applications of Re as well as the different therapeutic approaches and imaging techniques used in cancer therapy. In addition, the current application and future challenges and opportunities of Re are also discussed.

Liposomes containing phosphatidylcholine have been widely used as adjuvants. Recently, we demonstrated that B-1 cells produce dipalmitoyl phosphatidylcholine (DPPC)-specific IgM upon immunization of BALB/c mice with DPPC-liposomes encapsulating ovalbumin (OVA). Although this preparation enhanced the OVA-specific humoral response, the contribution of anti-DPPC antibodies to this effect was unclear. Here, we demonstrate that these antibodies are secreted by B-1 cells independently of the presence of OVA in the formulation. We also confirm that these antibodies are specific for phosphocholine. The anti-OVA humoral response was partially restored in B-1 cells-deficient BALB/xid mice by immunization with the liposomes opsonized with the serum total immunoglobulin (Ig) fraction containing anti-phosphocholine antibodies, generated in wild type animals. This result could be related to the increased phagocytosis by peritoneal macrophages of the particles opsonized with the serum total Ig or IgM fractions, both containing anti-phosphocholine antibodies. In conclusion, in the present work it has been demonstrated that phosphocholine-specific antibodies improve T-dependent antibody responses against OVA carried by DPPC-liposomes.