Vylan Nguyen

Introduction: Cytomegalovirus (CMV) is the most common cause for non-genetic sensorineural hearing loss and congenital infection in childhood¹. More than 50% of symptomatic cases among neonates present with central nervous system abnormalities². Long term effects include the virus’ contribution to atherosclerotic progression and cardiovascular disease³. While ganciclovir and Valganciclovir antivirals can be given to affected transplant patients, such medications may be teratogenic and have long term effects on neonates; further failure of hyperimmune globulin to reduce congenital infection highlights lacks of intervention methods after infection has occurred⁴. Although counseling-based intervention with hygiene is the best prevention method available, a primary infection in the mother is highly likely to cross the placenta and infect the fetus². Previous research found MF59- adjuvanted monomeric glycoprotein B (gB), a trimeric virion complex, to be 50% efficient in preventing CMV infection⁵. Methods: Cross-linked and native human CMV gB was isolated and purified via size exclusion and affinity and chromatography before transfer to view on a transmission electron microscopy⁵. DNA constructs of recombinant gB, antigenic domain (AD) 2, AD4, and AD5 were codon-optimized for expression in human cells; trimeric AD5 design was based on the gB crystal structure⁶. Trimeric AD5 was designed and docked to I5350 and Ferritin nanoparticles and subsequently assembled and given to mice on days 0, 21, and 35 of experiment, and sera was collected on day 45 to measure binding and neutralization titers⁶. The binding of sera and mAbs to the tested proteins were determined using an ELISA assay, where antibody binding was shown using either goat anti-human IgG antibody coupled to alkaline phosphatase (AP) or goat anti-mouse IgG antibody, also coupled to AP. Results: Detailed resolution of the gB structure reveals tripod-like structure with fusion loops towards anchoring membrane, allowing for novel potential for vaccine development with increased specificity in structure targeting⁵. AD5 is the main target of gB neutralizing antibodies, inducing significant antibody titers⁶. When fused to hyper-stable nanoparticles, especially Ferritin, antigen stability and effectiveness is increased; trimeric AD5 (trAD5)- nanoparticles elicit higher neutralization compared to soluble, monomeric AD5 and gB_ECD⁶. Conclusion: For future vaccine development, increasing specificity towards AD5 may increase neutralization effect of vaccine⁶. Incorporating AD5 into a nanoparticle-based vaccine, along with novel visualization of the gB structure, can allow for specific, self- assembling of large complexes with multiple gB trimers against CMV^5,6. Future work may yield higher efficacy than the MF-59 adjuvanted gB vaccine previously tested⁵.

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