Pegylation of antibody fragments improves their local bioavailability following pulmonary delivery
(2014)
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- Authors
- Supervisors
- Vanbever, Rita
- Abstract
- In the field of therapeutic proteins, monoclonal antibodies (mAbs) are gaining momentum as an important class of biopharmaceuticals. They are of particular therapeutic interest due to their high specificity in binding to their target molecules. Antibody fragments can provide an effective alternative to full-length antibodies. Although inhalation of antibody constructs is an attractive approach for local targeted therapy, the therapeutic efficacy of inhaled proteins is limited due to efficient pulmonary defense mechanisms (mucociliary clearance, alveolar macrophage uptake, enzymatic degradation, and transportation to the bloodstream) provided by nature. To this end, attachment of polyethylene glycol (PEG) chains to proteins can be used to increase their retention within the lung in intact form. The main objective of this thesis was to evaluate the effects of PEGylation of antibody fragments on their local bioavailability and therapeutic efficacy following delivery to the respiratory tract. As such, a mono-PEGylated F(ab')2 anti-interleukin-17A (anti-IL-17A) antibody fragment (98 kDa) with one branched chain of 40 kDa was produced using amino-directed PEGylation. The conjugate presented only a slight decrease in its binding activity and in its in vitro inhibitory potency offering interesting potential for in vivo studies. Anti-IL-17A was chosen for modification as it can be used for the neutralization of IL-17, an interleukin that is implicated in asthma pathogenesis. An in vivo pharmacokinetic study demonstrated that the mono-PEGylated anti-IL-17A antibody fragment remained significantly longer in the lungs than its unconjugated counterpart following administration to the respiratory tract. To further generalize the observation, the study was repeated using another PEGylated protein, a murine Fab’ anti-IL-13 (47 kDa) linked to a single branched 40 kDa PEG. The outcome was positively confirmed. Moreover, the PEGylated anti-IL-17A F(ab’)2 showed improved therapeutic efficacy to reduce lung inflammation in a murine model of house dust mite-induced lung inflammation. The data obtained in this work suggested mucoadhesion as the principal property offered by PEG to antibody fragments that led to their pulmonary retention, rather than increased hydrodynamic size, enzymatic stability or escape from alveolar macrophages. This thesis thus indicated that PEGylation of proteins with large PEGs offers enhanced local activity due to their increased lung retention compared to their unconjugated counterparts. Furthermore, mucoadhesion of the conjugates offered by PEG appears to play a key role in their prolonged residency in the lungs. This approach opens promising perspectives in the field of pulmonary drug delivery of proteins.
- Affiliations
Citations
Koussoroplis, S. (2014). Pegylation of antibody fragments improves their local bioavailability following pulmonary delivery. https://hdl.handle.net/2078.5/199739