# Development of VLP vaccine for RSV

> **NIH NIH R44** · SIGMOVIR BIOSYSTEMS, INC. · 2020 · $1,000,000

## Abstract

Respiratory syncytial virus (RSV) is a significant human pathogen severely
impacting neonates and young children, but no vaccine exists to protect this vulnerable
population. Furthermore, direct vaccination of neonates is likely ineffective due to the
immaturity of their immune system, and neonate immunization is potentially unsafe. The
current view is that maternal vaccination is the best and safest approach to protection of
neonates through the passive transfer of maternal neutralizing antibodies in utero to the
fetus after maternal immunization. However, a complicating issue is that most people
have experienced RSV infections during their lifetimes. Thus, any maternal vaccine
must induce high levels of protective antibodies in the presence of pre-existing, but very
poorly neutralizing, anti-RSV antibodies.
 In our STTR phase IIa project, we tested our novel RSV VLP vaccine candidates
in pregnant cotton rats, a surrogate human model, to determine the effect of prior RSV
exposure on induction of protective immune responses in these animals and to assess
maternal antibody transfer, protection, and safety in offspring of the immunized dams.
Our results showed that a single VLP immunization of RSV primed cotton rats stimulated
high titers of NA. Furthermore, VLP immunization of dams protected their offspring from
RSV challenge and decreased pathology in pups' lungs compared to pathology
observed after RSV infection of offspring of unimmunized dams. We also found that
maternal immunizations with VLPs containing different versions of the pre-fusion F
protein varied significantly in the extent of protection of offspring of vaccinated dams. We
identified one version of pre-fusion F VLPs that improved protection of offspring ten-fold
compared to the originally tested pre-F VLP.
 It is our goal to move our VLP vaccine candidates toward clinical trials as a
maternal vaccine. To this end, we propose three specific tasks using cotton rats as
human surrogates.
Task 1: Develop protocols and processes for production and purification of cost
effective GMP VLP vaccine candidates on a large scale.
Task 2: Refine parameters of protection of neonates after maternal immunization.
Task 3: Assess and improve protective responses in mothers post-delivery.

## Key facts

- **NIH application ID:** 9897525
- **Project number:** 5R44AI109926-05
- **Recipient organization:** SIGMOVIR BIOSYSTEMS, INC.
- **Principal Investigator:** JORGE C BLANCO
- **Activity code:** R44 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $1,000,000
- **Award type:** 5
- **Project period:** 2014-02-15 → 2022-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9897525

## Citation

> US National Institutes of Health, RePORTER application 9897525, Development of VLP vaccine for RSV (5R44AI109926-05). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9897525. Licensed CC0.

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