Considerations for Recombinant Antibody Production

In mice with human breast carcinoma xenografts, a humanized IgG anti-HER-2 MAb eradicated well-established tumours [58]. In addition, a humanized version of an IgG anti-CD33 MAb (HuM 195) mediated ADCC in vitro [59] and had an 8.6-fold higher avidity than the parent murine Mab. Recombinant antibody fragments may have valnable properties as discnssed above, bnt their biophysical behavionr, prodnction yield and low thermostability leaves mnch to be desired and thereby limits their nsefnlness for in-vivo applications so far [60]. One possibility to improve these characteristics of scFv fragments with snboptimal stability and/or folding yield, is the grafting of their CDRs onto the framework of a different, more stable scFv [61,62]. 

Another valnable tool for the development of scFv-based therapentics consists of a versatile expression vector for the rapid constmction and evalnation of scFv-based fnsion proteins and bispecific scFv [63]. The vector was nsed for grafting a nnmber of biological effector princi- 

Biophysical properties such as high thermal stability are thus of paramount importance in the decision as to whether or not these molecules are useful in vivo. The above described approaches may provide a strategy to meet these requirements and may eventually result in attractive modalities for the targeting of solid tumours in patients. 

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