Development of a vaccine candidate based on virus-like particles and an immuno-stimulant adjuvant against Zika virus capable of inducing a strong mucosal response.

LUCIANA AGOSTINA FASSOLA; GUILLERMO ALBRIEU-LLINÁS; FELICITAS ANTONINO; LUCIA L RUPIL; PERALTA, DAMIÁN O.; MARIANELA C SERRADELL

San Luis

Congreso; LXXI Reunión Científica Anual de la Sociedad Argentina de Inmunología SAI; 2023

Sociedad Argentina de Inmunología SAI

Virus-like particles (VLPs) are a type of subunit vaccines that possess diverse applications in therapeutics, immunization, and diagnostics. On one hand, VLPbased vaccines are being extensively used because of their efficacy, safety and diversity. On the other hand, Giardia lamblia variable surface proteins (VSPs) have been shown to act as adjuvants and endure extreme conditions. These protozoan proteins can be used to generate oral vaccines due to their outstanding resistance to proteases and to changes in pH, immunogenicity and absence of toxicity. Previously, using an Influenza viral model, it was shown that surface decorated VLPs with VSPs triggered a successful immune response after oral and subcutaneous immunization with hemagglutinin glycoprotein. Considering the increasing global impact of arboviruses, our goal is to develop a safe and effective vaccine against Zika virus (ZIKV, Flavivirus) using VLP-VSP in conjunction with specific viral antigens. ZIKV infection causes an acute febrile disease including rash, conjunctivitis and arthralgia, and it is also associated with complications such as Guillain-Barré syndrome and complex congenital disorders. So far, there are no available vaccines against ZIKV, which is spread not only by hematophagous mosquitoes but also sexually among humans. In this context, for an optimal Zika vaccine, ensuring safety is of utmost importance, particularly when considering its administration to pregnant women. Additionally, the vaccine should elicit a robust mucosal response to effectively counteract sexual transmission. In this sense, the VLP-VSPs platform fulfills the safety criteria owing to the absence of viral genome and its adaptability foradministration through various routes. At the outset, we amplified and insertedthe gene encoding the ZIKV-E into a mammalian vector (pEZIKV). We then verified its accurate expression in different cell lines through immunofluorescence observation. For the production of VLPs, we co-transfected HEK cells that constitutively express specific r Giardia VSP (VSP1267) with two plasmids: one encoding the Murine Leukemia Virus capsid, promoting the subsequent selfassembly of the VLPs (pMLV-Gag) and pEZIKV. This approach led to the successful expression of the ZIKV E glycoprotein in VLP-VSP constructs. The proper assembly was confirmed by Western blotting and transmission electron microscopy (TEM), using anti-Zika E antibodies. Finally, we assessed the immune response in Balb/c mice by administering VLP-VSP-EZIKV through bothoral and subcutaneous routes. The presence of anti-ZIKV antibodies, confirmed by ELISA, verified the humoral response in both serum and mucosal samples. Additionally, ongoing analysis of the cytokine profile is underway. The data were analyzed by one-way ANOVA followed by Tukey’s multiple comparison test. Our findings demonstrate the capacity to produce targeted antibodies using a secure vaccine that can accommodate various administration protocols.