# Armed nanobodies as anti-infectives and anti-tumor agents

> **NIH NIH R01** · BOSTON CHILDREN'S HOSPITAL · 2024 · $542,900

## Abstract

Summary
A nanobody that recognizes immunoglobulin light chains, conjugated to a molecular entity that recognizes a
virus-infected or a cancerous cell, is an effective therapeutic: A single injection of fusion constructs comprising
an anti-kappa light chain nanobody (VHHkappa) and zanamivir, a small molecule that targets influenza
neuraminidase, protects mice from a lethal challenge with both A- and B-strains of influenza. In the model that
established protection by VHHkappa adducts against influenza, the underlying mechanism of action involves
antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC), but the
relative contribution of each is not known. We shall therefore use FcgR common g chain-deficient mice and C3-
deficient mice to assess the relative contributions of ADCC and CDC. The generation of Fc constructs of different
Ig isotypes and bearing FcR-engagement disabling mutations, similarly modified with zanamivir, will be used to
complement this analysis.
Having established proof-of-concept for influenza and optimized parameters for elimination of influenza virus-
infected cells, we will explore nanobodies that recognize other pathogens (Ebola virus, SARS-CoV-2, HIV) in
combination with VHHkappa in a series of collaborative experiments. The agents to be developed may inspire
novel immunomodulatory therapeutics, to be used as a stand-alone approach, or in combination with approved
drugs. The possibilities of post-exposure prophylaxis against viral infections (Ebola, SARS-CoV-2, HIV) in the
absence of pre-existing immunity, deserve particular emphasis. We shall further enhance the activity of the
proposed VHHkappa fusions through the generation of the corresponding drug adducts, using cytotoxic drugs such
as maytansinoids as compounds that have shown clinical utility. Enveloped viruses (e.g., HIV, SARS-CoV-2)
export viral proteins to the surface of the infected cell during budding. Infected cells can thus be distinguished
from uninfected cells based on the surface display of viral proteins.
We now extend these in vivo observations to fusions of VHHkappa with anti-checkpoint (PD-L1, CTLA-4)
nanobodies. We generated maytansinoid-modified VHHkappa fusions with the anti-PD-L1 and anti-CTLA-4 VHHs.
Our preliminary data show enhanced anti-tumor activity in the MC38 and B16.F10 mouse tumor models in
comparison with commonly used monoclonal antibodies. However, not all such fusions (examples: fusions of
VHHkappa with nanobodies that recognize Class II MHC or CD8) have shown the intended depletion efficacy in
vivo. This proposal seeks to establish the parameters -including biodistribution and surface expression levels of
the targeted molecules- that determine success or failure of VHHkappa fusions. The availability of VHHs that
recognize human kappa light chains suggest the possibility of clinical translation of this approach.

## Key facts

- **NIH application ID:** 10858819
- **Project number:** 1R01AI182177-01
- **Recipient organization:** BOSTON CHILDREN'S HOSPITAL
- **Principal Investigator:** Hao Wu
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $542,900
- **Award type:** 1
- **Project period:** 2024-07-19 → 2029-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10858819

## Citation

> US National Institutes of Health, RePORTER application 10858819, Armed nanobodies as anti-infectives and anti-tumor agents (1R01AI182177-01). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10858819. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*