bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/2025.02.04.636391

Replication-Deficient Whole-Virus Vaccines Against Cytomegalovirus Induce Protective Immunity in a Guinea Pig Congenital Infection Model

Schleiss, M. R.·Fernandez-Alarcon, C.·Bierle, C. J.·Geballe, A. P.·Badillo-Guzman, A. J.·Tanna, C. E.·Tsriwong, K.·Blackstad, M.·Wang, J. B.·McVoy, M. A.
View original source ↗Export metadata ↓

Abstract

Vaccines are needed to prevent congenital cytomegalovirus (CMV) infections. This study used the guinea pig cytomegalovirus (GPCMV) model to examine replication-deficient whole-virus vaccines against maternal viremia and congenital infection. Two recombinant GPCMVs, GP51-DD and GP52-DD, were engineered with destabilization domains fused to essential viral late proteins GP51 and GP52. These viruses, predicted to replicate in the presence of the synthetic ligand Shield-1 but not in its absence, were evaluated for Shield-1-dependence in vitro and for safety, immunogenicity, and efficacy in a pregnancy/challenge model. GP52-DD was profoundly Shield-1-dependent, producing no detectable infectious progeny in its absence. In contrast, the replication of GP51-DD was delayed in the absence of Shield-1, but the virus reached similar peak titers with or without the compound. GPCMV-seronegative guinea pigs received two subcutaneous injections of placebo (sham-immunized), GP51-DD, GP52-DD, or wild-type GPCMV (WT-GPCMV). DNAemia post-vaccination was detected in only one of 14 dams in each of the GP51-DD- and GP52-DD-immunized groups compared to 10/10 control animals immunized with WT-GPCMV, confirming the recombinant viruses were attenuated. GPCMV-specific antibody responses were similar in all three vaccinated groups. When immunized dams were bred and challenged with virulent GPCMV, DNAemia was detected in all sham-immunized controls and in 44% of GP52-DD-immunized dams (at significantly reduced levels) but was absent in dams immunized with GP51-DD or WT-GPCMV. Notably, immunization with GP52-DD, GP51-DD, or WT-GPCMV significantly reduced congenital GPCMV transmission (protective efficacies of 89%, 94%, and 100%, respectively). Thus, the replication-deficient GP52-DD vaccine was attenuated and protected against intrauterine GPCMV transmission. ImportanceCongenital cytomegalovirus (CMV) infections could be prevented by a vaccine, but most of the vaccine designs that have advanced to clinical trials have been subunit vaccines. These viral envelope glycoprotein-targeting designs have not yielded an effective vaccine that provides durable immunity. A vaccine that confers immune responses to a broader repertoire of viral immunogens, such as vaccines based on the whole virus, could enhance protection. However, there are concerns about the safety of live attenuated CMV vaccines. Using the guinea pig/guinea pig cytomegalovirus model of congenital infection, this study demonstrates that two replication-deficient whole virus vaccines are attenuated in animals while also being highly immunogenic, providing protective immunity against maternal viremia and fetal infection at levels similar to that conferred by a wild-type virus.

Source connections

Explore related subjects

immunologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Schleiss, M. R., Fernandez-Alarcon, C., Bierle, C. J., Geballe, A. P., Badillo-Guzman, A. J., Tanna, C. E., Tsriwong, K., Blackstad, M., Wang, J. B., McVoy, M. A.. 2025-02-10. Replication-Deficient Whole-Virus Vaccines Against Cytomegalovirus Induce Protective Immunity in a Guinea Pig Congenital Infection Model. https://doi.org/10.1101/2025.02.04.636391

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Melanoma suppresses galectin-9-glycan axis in dendritic cells and galectin-9 restoration limits T regulatory cell expansion

Dendritic cells (DCs) are key orchestrators of anti-tumor adaptive immune responses. Their function is tightly regulated by galectins, a family of carbohydrate-biding proteins that decode extracellular glycans into intracellular signaling. Here, we show that exposure to melanoma-conditioned media (CM) induces loss of galectin-9 (gal-9) at the DC surface. Notably, gal-9 loss, independent of transcriptional regulation, was associated with the acquisition of an immunosuppressive phenotype in CD14cDC2 cells following tumor exposure, with higher-molecular weight fractions of the melanoma secretome as mediators. Notably, gal-9 depletion was mirrored with a reduction in gal-9 ligands on the cell surface, particularly GalNAc-containing glycoepitopes, pointing towards a melanoma-exploited gal-9-glycan axis as a DC-evasive strategy. Interestingly, restoring gal-9 surface levels in CM-exposed CD14cDC2 cells prevented the expansion of regulatory T cells (Tregs), postulating gal-9 as a novel immunomodulatory molecule in DC-mediated Treg induction during melanoma progression. Altogether, our data suggest that melanoma-derived factors remodel the DC glycan-gal-9 axis to enhance T cell differentiation towards regulatory phenotypes and dampen anti-tumor immunity. This identifies the gal-9/glycan axis in CD14cDC2 cells as a vulnerable node in melanoma immune evasion and as a potential therapeutic target.

immunology↗
bioRxiv2026

Repeated shrimp allergen exposure drives 5-lipoxygenase-dependent avoidance and selective gut-brain activation

Peripheral immune processes can shape animal behavior, yet how noninfectious inflammatory reactions affect neural activity and behavioral outputs remains poorly understood. We developed an optimized murine model of shrimp allergy using whole shrimp extract to examine how a complex dietary allergen elicits integrated immune, neural, and behavioral responses. Sensitized mice received repeated oral shrimp challenges and were assessed for allergic pathology, food preference, affective-like behaviors, and neuronal activation in the brain. Repeated exposure increased total IgE and shrimp-specific IgG1, induced mast cell activation, accelerated gastrointestinal transit, caused mild hypothermia consistent with oral anaphylaxis, and increased intestinal length. Shrimp-sensitized mice did not avoid shrimp solution after sensitization alone. Instead, avoidance emerged only after repeated oral challenges and strengthened over time. This delayed aversion occurred without detectable changes in locomotor activity or measures of anxiety-like or depressive-like behavior at the time points tested. Repeated shrimp exposure increased cFOS expression in the area postrema, nucleus of the tractus solitarius, central amygdala, and paraventricular nucleus of the thalamus, implicating brainstem and limbic-thalamic pathways involved in visceral sensing and aversion. Pharmacological inhibition of 5-lipoxygenase partially reversed avoidance and reduced circulating mast cell protease-1 in allergic mice. These findings establish a robust whole-shrimp allergy model and show that a complex food allergen engages gut-brain pathways to promote 5-lipoxygenase-dependent avoidance. The delayed, selective nature of this response supports immune-mediated food aversion as a shared output of food allergy, while suggesting that its kinetics and neural recruitment vary with allergen identity and inflammatory context.

immunology↗
bioRxiv2026

Targeting IL-2 to inflamed tissues via oxidation-specific epitopes enables third-generation bispecific IL-2 therapeutics

Interleukin-2 (IL-2) is essential for the survival and activation of regulatory T cells (Tregs). Low-dose native IL-2 (IL-2LD) therapy restores immune regulation in vivo and has shown reproducible clinical benefit across multiple autoimmune, inflammatory, and neuroimmune diseases. Attempts to improve IL-2 through engineered variants (muteins) have mainly focused on enhancing Treg selectivity by reducing IL-2 receptor {beta}-chain binding, but this strategy profoundly diminishes biological potency, likely contributing to the limited clinical efficacy of IL-2 muteins. Here, we develop a ''third-generation IL-2'' that combines site-specific targeting and bifunctionality. We generated a bivalent fusion protein linking IL-2 to a single-chain antibody recognizing oxidation-specific epitopes (OSEs), which are abundantly expressed at inflamed sites. Targeting OSEs provides not only site-specific localization, but also true bifunctionality as both anti-OSE antibodies and IL-2LD independently show therapeutic benefit in limiting inflammation. We first show that IL-2IT has bifunctional biological activities in vitro. In vivo, IL-2IT had increased specificity for Treg over Teff activation, which we attribute to a conformation-dependent modulation of IL-2 receptor engagement. Importantly, IL-2IT provided precise delivery to inflamed tissues in models of psoriasis and colitis. Altogether, this resulted in superior therapeutic benefit in multiple clinical settings, including in atherosclerosis models. Thus, our strategy illustrates a generalizable approach to cytokine engineering that preserves native signaling while achieving spatial control. Specifically, our findings validate OSE targeting as an efficient strategy to guide therapeutics to sites of inflammation and establish OSE-IL-2 as a promising bispecific Treg engager for treating inflammation.

immunology↗