[CCoE Notice] Cullen College Dissertation Defense Announcement - Suman Nandy - ChBE

[Hutchinson, Inez A]

[Dissertation Defense Announcement at the Cullen College of Engineering]

Developing novel applications of engineered protein A: Bioseparations, Diagnostics, and Process Analytics



Suman Nandy



December 1, 2023; 3:00 PM

Location: Agrawal Engineering Research Building (AERB), Room 126



Zoom:
https://urldefense.com/v3/__https://us02web.zoom.us/j/89095209706?pwd=dDZMZ2lKOEI2RHJob1VLS3pVNk0zZz09__;!!LkSTlj0I!FcIAS9ofU_MpMrcWJt_2ihlg9_e7X_us6a0gONyl6F-k9Crt3dZCsFGkbYWnSIMwq2aZnzW_8_s7WE_IvTAjGSb09G0$ 

Meeting ID: 890 9520 9706

Passcode: 787037



Committee Chair:
Richard C. Willson, Ph.D.



Committee Members:
Patrick C. Cirino, Ph.D. | Mehmet Orman, Ph.D. | Mehmet Sen, Ph.D. | Dmitri Litvinov, Ph.D. |

Katerina Kourentzi, Ph.D.| Binh Vu, Ph.D.| Ujwal Patil, Ph.D.



Abstract

Antibodies are a rapidly-growing class of pharmaceuticals due to their ability to specifically target and treat a wide range of diseases, ranging from cancers to infectious diseases and autoimmune disorders. Purification of antibodies utilizes affinity chromatography for high-specificity and cost-effective capture of antibodies from complex cell culture fluid. The most widely used affinity ligands are based on Staphylococcus aureus protein A (SpA), an antibody-binding virulence factor that aids in the organism’s pathogenicity. Since the protein A adsorbent accounts for a large fraction of the overall raw material and operating costs of antibody production, improvements in the affinity ligand and in chromatography operation can directly contribute to reducing the costs of many of the top drugs globally.



The first project described here focuses on enhancing SpA stability by topology engineering. A cyclized protein A ligand could offer exopeptidase resistance, reduced chromatographic ligand leaching after single-site endopeptidase cleavage, and enhanced IgG binding properties by preorganization, potentially reducing conformational entropy loss upon binding. In this work, we designed, purified, and characterized a cyclic trimer of the SpA Z domain (Z3). Interactions of cyclic and linear Z3 with human IgG1 were characterized by differential scanning fluorimetry, surface plasmon resonance, and isothermal titration calorimetry. We observed that cyclization reduces conformational heterogeneity but found functional near-equivalence between cyclic and linear proteins.



We also sought to advance the real-time control of protein A column loading, to prevent the loss of expensive antibodies due to overloading and avoid expensive protein A capacity wastage by too-conservative underloading. Here, we developed an in-line, fiber optic-based antibody detection sensor consisting of a flow cell and a replaceable sensor tip, covalently functionalized with fluorophore-labeled engineered protein A. The fiber-optic sensor demonstrates repeatable and concentration-dependent fluorescence enhancement in the presence of human IgG and maintains its specificity in the presence of CHO cell culture fluid.

[Engineered For What's Next]


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