HighIn VivoProduction of a Model Monoclonal Antibody on Adenoviral Gene Transfer

Abstract

The therapeutic potential of monoclonal antibodies (MAbs) for treating a variety of severe or life-threatening diseases is high. Although intravenous infusion appears to be the simplest and most obvious mode of administration, it is not applicable in many long-term treatments. It might, however, be advantageously replaced by gene/cell therapies, rendering treatments cost-effective and eliminating the short- and long-term side effects associated with injection of massive doses of antibodies. Grafting of ex vivo genetically modified cells of various types has already been used for in vivo production and systemic delivery of MAbs in mice. However, although sustained for long periods of time, serum levels of ectopic MAbs were low. We show here that in vivo administration to mice of a first-generation adenoviral vector expressing a model MAb also permits achievement of the same goal, but with 100 to 200 times better efficiency that in any other case of gene transfer described thus far. We also investigated for possible anti-idiotypic response against the ectopic MAb. None was detected in the animals expressing the lowest levels of ectopic MAb production; a response was detected among the highest producers. In the latter case, however, the response was low and could not exert any significant neutralizing activity. In conclusion, our work indicates that high levels of circulating ectopic MAb can be obtained on direct in vivo gene transfer without inducing an anti-idiotypic response sufficiently robust to exert a neutralizing effect. This observation is encouraging in the perspective of clinical applications of this technology.

Gene Therapy Using Adenovirus-Mediated Full-length Anti-HER-2 Antibody for HER-2 Overexpression Cancers

“…In addition, we proved that the well-balanced coexpression of heavy and light chain was gained by this strategy. Adenovirus has been used for in vivo full-length antibody gene transfer and induced mouse mAb serum concentration >200 Ag/mL for >1 month in mice, although the antibody against adenoviral backbone was detected in the serum, indicating the possibility and rationality of adenoviral vector applied for delivering therapeutic antibody (41). However, mouse mAb expressed in mice activates much lighter and milder immune response than humanized mAb; moreover, there was no confirmation of antibody bioactivity in vitro and therapeutic effect in vivo reported in Noel's article.…”

Growth inhibition of an established A431 xenograft tumor by a full-length anti-EGFR antibody following gene delivery by AAV

“…However, the production of antibodies for both preclinical and clinical functions continues to be a bottleneck for antibody therapeutics. [4][5][6][7] The expression and purification of sufficient amounts of candidate antibodies required for preclinical in vivo validation studies can often be a labor, time and cost-intensive process. 4,5,[8][9][10] For most antibody therapies in the clinic, delivery requires lengthy infusions of large amounts of antibody.…”

“…This can result in suboptimal systemic levels and may create considerable side effects for the patient. 4,7,11 Particularly for the treatment of chronic disease such as cancer, high and sustained antibody levels often in the range of several hundreds of mgs per milliliter are required for therapeutic efficacy. 12 As an alternative to conventional methods, a gene-based delivery approach could expedite antibody delivery by bypassing in vitro expression and purification and advancing directly into antibody production in vivo.…”

Oncolytic Adenovirus Expressing Monoclonal Antibody Trastuzumab for Treatment of HER2-Positive Cancer

“…In such approaches, nontarget organs are used for production of an antibody into the systemic circulation, from which it must diffuse into tumors, just like with systemic delivery. In addition, these attempts have been hampered by low transduction, short-term expression, and/or immunological eradication of input virus, thus resulting in low antibody levels, including those found in the tumor (20)(21)(22)(23). Moreover, highdose viral transduction of the liver is not without its risks (41).…”

“…To date, gene therapy approaches featuring monoclonal antitumor antibodies have focused on production of antibodies from normal cells (20)(21)(22)(23). Meanwhile, it has remained unknown whether full-length antibodies can be produced directly from cancer cells because antibody production in humans is normally restricted to plasma cells (24).…”