Department of Immunology Harvard Medical School ......Department of Cancer Immunology and Virology Harvard Medical School Department of Immunology VHH Antibodies Small size (15 kDa)

The importance of inducing an adaptive response

Stephanie DouganMichael Dougan

Dana-Farber Cancer InstituteDepartment of Cancer Immunology and Virology

Harvard Medical SchoolDepartment of Immunology

VHH Antibodies

Small size (15 kDa) allows deep tissue penetration

Rapidly cleared after injection

Antibody targets: PD-L1, MHC class II, CD11b, CTLA-4, Tim3, CD47, CD8, PD-1, VISTA

Cross-reactive with human, or human-specific versions available

Phase II trial of a humanized VHH showed very little immunogenicity

Collaboration with Hidde Ploegh

Finding VHHs from live camelids by phage display

Sortase handles allow for easy molecular assembly

Ingram, Schmidt, Ploegh. Exploiting Nanobodies’ Singular Traits. Ann Rev Imm 2018

VHH against murine CD47

Sockolosky JT*, Dougan M* et al. PNAS 2016

VHH against murine CD47


Mouse CD47 Human CD47

A4 blocks binding of CD47 to mSIRPα


A4 outperforms miap301


A4 augments phagocytosis by the anti-B16 antibody TA99

Bone marrow derived macrophages cultured with CFSE labeled B16 cells for 2 hours

A4 augments phagocytosis of hEGFR-CT26 cells

Bone marrow derived macrophages cultured with CFSE labeled hEGFR-CT26 cells for 2 hours

A4 augments phagocytosis of via IFN-inducible PD-L1

Bone marrow derived macrophages cultured with CFSE labeled B16 cells for 2 hours

A4 augments phagocytosis of Tregs via CTLA-4

A4 stains CD47 brightly on many hematopoietic tissues


A4

aCD47

A4 alone does not cause anemia

CD47-IgG2a “microbody” as a model for anemia irAE

Ingram JR et al. PNAS 2017

A4 synergizes with PD-1 blockade in B16 melanoma


CT26 model is non-responsive


B16 melanoma

Underwhelming performance of A4


Underwhelming performance of A4 – inefficient blockade of CD47?


B16 engineered to secrete A4 locally – blocks its own CD47 in vitro


B16 engineered to secrete A4 locally – blocks its own CD47 in vivo


B16 engineered to secrete A4 locally + anti-tumor Ab leads to near complete survival


Vaccination can supply anti-tumor antibodies


Possible role for Treg phagocytosis


Concluding thoughts part I

Cross-linking of red blood cells can lead to fatal anemia – may be dependent on epitope positioning

Near complete coverage of CD47 is required for efficacy in melanoma – better local delivery is needed

Synergy with multiple antibodies including anti-PDL1 (IFN-inducible), anti-CTLA4 (Tregs), polyclonal Abs from vaccination

Role for engagement of Sirpα on other cell types

Heckler and Dougan, Gastroenterology 2018

Productive immunity is polyfunctional

Acknowledgements

Stephanie and Michael Dougan lab: Kevin Roehle, Eleanor Clancy-Thompson, Lestat Ali, Tamara Biary, Stephanie Crowley, Daniel Heid, Katherine Ventre, Max Heckler, Aladdin Bhuiyan, Patrick Lenehan, Gui Zhen Chen, Jana Tegethoff, Patrick Bruck, Jessica Ingram

BRIDGE project

Hidde Ploegh

Chris GarciaJonathan Sockolosky

David Knipe Steve AlmoMichael Walsh

Documents

Department of Immunology Harvard Medical School ......Department of Cancer Immunology and Virology Harvard Medical School Department of Immunology VHH Antibodies Small size (15 kDa)