1) Phage antibody libraries are a variant of the phage antigen libraries first invented by George Pieczenik.
2) All the recombinant antibody techniques rely on cloning the specific gene segments to create the libraries of antibodies. These libraries are specifically different in only few amino acids which decide their specificity.
3) These techniques are applied to improve the specificity with which antibodies recognize antigens, their stability in various environmental conditions, their therapeutic efficacy, and their detectability in diagnostic applications.
Monoclonal antibodies production from the fungal species is preferred over the E. coli as:
a) Antibodies produced from the fungal systems are extracellular which make protein separation process easier. However recovery of antibodies from the E. coli is very intricate due to its periplasm.
b) Common fungal organism exploited for the production of monoclonal antibodies with single chain is the Aspergillus niger.
c) Ward et al. expressed full-length IgGs in A. niger using an N-terminal fusion to glucoamylase for both light and heavy chains. They relied on the endogenous KexB protease in A. niger to cleave off the fusion during the secretion of the antibody. (Ward M et al , 2004)
d) Monomeric scFv production in P. pastoris was also demonstrated and optimized. (Cunha et al, 2004)
Figure7-3.4.1: Flow diagram of human mAb discovery process
(Acknowledgement: http://www.crucell.com/)
Improvements in the microbial production of antibodies and fragments have resulted from host-cell engineering to give increased and optimized productivity. There is also a trend of producing antibodies or fragments with increased circulating half-life
7-3.4.1 Applications of recombinant Monoclonal Antibodies:
a) Diagnostic Applications: Monoclonal antibodies can be used as a specific probe for developing biosensors and microarray systems.
b) Therapeutic Applications:
- Transplant rejection can be detected immediately with the MAB and CD marker conjugates.
- Most common monoclonal antibodies like Abciximab, Cetuximab are widely prescribed for the cardiovascular diseases and cancer respectively. For breast cancer treatment MAB like Herceptin is a breakthrough invention.
- For treatment of infectious diseases Palivizumab and Briakinumab are widely used whereas for the inflammatory diseases Infliximab are commonly used.
c) Future applications: By exploiting monoclonal antibodies we can combat against the terrorists who can cause threat using biological organisms (Bioterrorism).