(4ax) Exploiting Immune Function and Response for Biopharmaceutical Engineering

Biopharmaceutical drugs are defined as therapeutics and in vivo diagnostics engineered from a biological source. Nearly half of all clinically approved biopharmaceuticals are comprised of subunit vaccine and antibody-based therapeutics; of which, their development has been heavily reliant on applied immunology (i.e., hybridomas and recombinant vaccine antigens). Here, I will describe novel approaches that exploit immune function and response for vaccine and antibody engineering.

Subunit vaccine development is often focused on antigen targeting and adjuvancy schemes that respectively facilitate delivery of antigen to dendritic cells and elicit their activation. Here I will present a novel polymer nanoparticle-based vaccine platform, which targets lymph node? residing dendritic cells via interstitial flow and activates these cells by in situ complement activation. After intradermal injection, interstitial flow transported ultra-small nanoparticles (25 nm) highly efficiently into lymphatic capillaries and their draining lymph nodes. The surface chemistry of these nanoparticles activated the complement cascade, generating a danger signal in situ and potently activating dendritic cells. Using nanoparticles conjugated to the model antigen ovalbumin, the generation of humoral and cellular immunity was shown in mice in a size- and complement- dependent manner. Such a vaccine technology platform is both effective and inexpensive, and therefore allows it to be explored in global health applications.

The ability of humoral B cell immunity to generate a vastly diverse antibody repertoire as a response to stimuli (i.e., immunization) has been substantially exploited for monoclonal antibody discovery. Here, I will present a novel technology for monoclonal antibody discovery that exploits high-throughput DNA sequencing of B cell antibody repertoires from immunized mice. It was found that antigen-specificity of antibodies could be identified based on sequence analysis of the immune repertoire; subsequently we utilized automated synthetic gene construction for the production of antigen-specific antibodies in recombinant expression systems. This work illustrates the potential to apply high-throughput DNA sequencing for molecular and protein engineering applications. Taken within the context of the rapid advances and declining costs for DNA sequencing and gene synthesis, this technology offers a powerful alternative to conventional methodologies for monoclonal antibody discovery (e.g., hybridoma and phage/microbial display screening). In addition to antibody discovery technology, we have also engineered antibody effector functions. We have used a bacterial display screening system to isolate aglycosylated IgG antibody variants that bind with high affinity and selectivity to activating Fcγ receptors on the surface of immune cells. Importantly, anti-Her2 aglycosylated IgG variants (targeting breast cancer specific receptors) bound to FcγRI and exhibited a unique ability to activate human monocyte-derived dendritic cells (mDCs) to kill target breast cancer cells. The antibody-mediated activation of mDC cytotoxicity may be of clinical value in antibody-mediated immunotherapy.

1. S.T. Reddy, X. Ge, A. Miklos, R. Hughes, S.H. Kang, K.H. Hoi, C. Chrysostomou, S.P. Hunicke-Smith, B.L. Iverson, P.W. Tucker, A.D. Ellington, G. Georgiou, Isolation of monoclonal antibodies without screening by mining the variable gene repertoire of plasma cells, Nature Biotechnology, 28 (9): 965-969, (2010).

Featured by:Cell: Select Leading Edge in Biotechnology Nov 2010; Biotechniques News 10/5/2010

2. S.T. Reddy, S.M. Carroll, K.H. Hoi, X. Ge, and G. Georgiou, Quantitative analysis of the naive B cell repertoire in a humanized mouse model, (In preparation).

3. S.T. Reddy, K.H. Hoi, X. Ge, C. Chrysostomou, P.W. Tucker, A.D. Ellington, G. Georgiou, High-throughput DNA sequencing of B cell populations in secondary lymphoid organs of immunized mice reveals distinct immunoglobulin repertoires, (In preparation).

4. J.J. Lavinder, S.T. Reddy, K.H. Hoi, X. Ge, A.D. Ellington, G. Georgiou, Isolation of monoclonal antibodies from multiple species by high-throughput DNA sequencing and bioinformatic analysis, (In preparation).

5. S.T. Jung, S.T. Reddy, T.H. Kang, M.J. Borrok, I. Sandie, P.W. Tucker, G. Georgiou, Aglycosylated IgG variants expressed in E. coli that selectively bind FcγR1 potentiate tumor cell killing by monocyte-dendritic cells, Proc. Nat. Acad. Sci. USA, 107(2): 604-609, (2010).

Featured by:Nature Biotech Research Highlights, 28(1): 45, (2010); Nature Science-Business Exchange , 3(3): 1-5, (2010)

6. A. Mercanzini, S.T. Reddy, D. Velluto, P. Colin, A. Maillard, J.C. Bensadoun, J.A. Hubbell, P. Renaud, Controlled release nanoparticle embedded coatings reduce the tissue reaction to neuroprostheses, J. Cont. Rel., 145(3): 196-202, (2010).

- Cover article

7. H.Y. Lim, J.M. Rutkowski, J. Helft, S.T. Reddy, M.A. Swartz, G.J. Randolph, V. Angeli, Hypercholesterolemic mice exhibit lymphatic vessel dysfunction and degeneration. Am. J. Pathol., 175(3): 1328-37, (2009).

8. M.A. Swartz, J.A. Hubbell, and S.T. Reddy. Lymphatic drainage function and its immunological implications: From dendritic cell homing to vaccine design. Seminars Immunol, 20(2): 147-56, (2008).

9. S.T. Reddy, A.J van der Vlies, E. Simeoni, V. Angeli, G.J. Randolph, L.K. Lee, M.A. Swartz, and J.A. Hubbell. Exploiting lymphatic transport and complement activation in nanoparticle vaccines. Nature Biotechnology, 25(10): 1159-64, (2007).

Featured by:Nature Nanotechnology Research Highlights, 10(1): (2007); Faculty of Biology 6.0 ? Must Read

10. S.T. Reddy, M.A. Swartz, and J.A. Hubbell. Targeting dendritic cells with biomaterials: developing the next generation of vaccines. Trends Immunol. 27(12): 573-579, (2006).

11.S.T. Reddy, A. Rehor, H.G. Schmoekel, J.A. Hubbell, and M.A. Swartz. In vivo targeting of dendritic cells in lymph nodes with poly(propylene sulfide) nanoparticles. J. Control. Rel. 112(1): 26-34, (2006).

- Top 10 most cited article - J. Controlled Release 2007

12. S.T. Reddy, D.A. Berk, R.K. Jain, and M.A. Swartz. A sensitive in vivo model for quantifying interstitial convective transport of injected macromolecules and nanoparticles. J. Appl. Physiol, 101(4): 1162-1169, (2006).