Stearns, K. | Search bioRxiv

bioRxiv2025

Stabilized Full-Length Measles Fusion Protein Elicits Potent Immunity and Protection In Vivo

Measles virus (MeV) is a highly contagious pathogen that causes significant morbidity and mortality in populations with low vaccination coverage. Infection typically leads to immune amnesia and, in rare cases, fatal neurological disease. While current live-attenuated vaccines are highly effective, they primarily elicit neutralizing antibodies against the hemagglutinin (H) glycoprotein, with a less robust response to the fusion (F) protein, a key protein for viral entry. To improve the immunogenicity of the F protein, we designed and characterized stabilized, prefusion MeV F protein antigens. We engineered both soluble ectodomains (FECTO) and full-length, membrane-embedded proteins (FFL) with mutations that confer thermal stability. Cryo-electron microscopy confirmed that these engineered antigens faithfully maintain the native prefusion conformation. When evaluated in a cotton rat model, immunization with either FECTO or FFL constructs induced neutralizing antibodies and elicited protection against viral challenge. The most stable full-length construct (FFL 3M) elicited a more potent neutralizing antibody response than its ectodomain counterpart. Importantly, no evidence of vaccine-enhanced respiratory disease was observed. These findings establish that a thermostable, full-length F protein is a superior immunogen to its soluble ectodomain. This work presents a promising candidate for next-generation, non-replicating measles vaccines intended to complement current vaccination strategies and provide a safe option for immunocompromised individuals and others who cannot receive live-virus vaccines. One-Sentence SummaryA prefusion-stabilized, full-length measles Fusion glycoprotein immunogen induces strong neutralizing responses and offers protection against challenge with wild-type virus.

immunology↗

bioRxiv2019

Alpha-1 Antitrypsin Antisense Oligonucleotide Modulates Protease-Antiprotease Imbalance without Further Aggravating Smoke-induced Lung Injury

Alpha-1 antitrypsin (AAT) is a serum protease inhibitor that prevents lung injury from protease production during cigarette smoking but causes severe liver disease once mutated. A custom AAT antisense oligonucleotide (ASO) was found to be beneficial for the AATD liver disease by blocking the mutated AAT transcripts. Here we hypothesized that knock-down of AAT aggravates murine lung injury during smoke exposure and acute exacerbations of chronic obstructive pulmonary disease (COPD). C57BL/6J mice were randomly divided into 4 groups for each of the injury models, smoking (inhale for 3 months at 150mg/m3) and smoke-flu (inhale for 2 weeks and intranasal influenza virus). The ASO and control (No-ASO) were injected subcutaneously at 10ml/kg of body weight, starting with smoking or four days prior to influenza infection weekly at 50mg/kg. ASO treatment during a 3 month smoke exposure significantly increased the expression of Cela1 mRNA and decreased the serum and lung AAT expression. However, despite the decrease in AAT, neither the inflammatory cell counts in the bronchoalveolar lavage fluid (BALF) nor the lung structural changes were significantly affected by ASO treatment. We observed significant differences in inflammation and emphysema due to smoke exposure alone. With the smoke-flu model, similarly the major differences were found between smoke-flu and room air control, with no additional effect with ASO treatment. Off-target effects or compensatory mechanisms may account for this finding. Alternatively, the reduction of AAT with ASO treatment was not robust enough to lead to lung injury. The result also suggest that the AAT ASO approach for treating liver disease is relatively safe at the specified dose as it did not lead to detrimental outcomes in the lung. These potential mechanisms need to be further investigated in order to fully understand the impact of AAT inhibition on protease-antiprotease imbalance in the murine smoke exposure model.

physiology↗