With recombinant
lysate, a recombinant protein is an artificially produced (and often purified)
protein. The recombinant process occurs, in general terms, when recombinant DNA
encoding a protein is introduced into a host organism to express foreign
proteins. This process requires the use of specialized expression vectors
together with restructuring by foreign coding sequences.
Tim Sandle has
written a review of recombinant lysate for use with the bacterial endotoxin
test.
The idea for the
use of recombinant lysate is to provide a reagent that reacts in the same way
as the natural cascade within the four species of horseshoe crab: (Limulus
polyphemus, Tachypleus tridentatus, Tachypleus gigas, and Carcinoscorpius
rotundicauda). The cloning technology serves an alternative to the fishing
and bleeding of horseshoe crabs (where bleeding is performed through a large
dorsal blood sinus called the pericardium). In addition, the use of recombinant
technology to substitute the specific pathway seeks to address the concern with
some lysates that also detect beta glucans through the activation of factor G.
A further advantage with recombinant lysates stems from the production of the
test reagent through the use of cell culture. This may result in the supply of a more
consistent product.
From around 2003
recombinant lysate has been commercially available, albeit not recognized by
any compendia until 2016. However, it has only been in the past few years that
manufacturing has become more consistent and subsequently a number of quality
control testing laboratories have been looking into the use of recombinant
lysate. This somewhat gradual process is attributable to a clash between
drivers (seeking to conserve horseshoe crabs, albeit with the mortality rate an
imprecise and often contested figure)4 and points of hesitancy (regulatory
uncertainty, lack of standardization, imprecise validation requirements and so
on). As of 2021, recombinant lysate will become an established alternative to
the traditional LAL test within Europe but within the U.S., when a new chapter
appears, a greater level of comparative validation will be required in order to
show equivalence. While this disparity is understandable, and this article
attempts to show this through a discussion of the historical perspective, the
current situation is a disservice to laboratory users. Much of what has been
written on rFC to date has looked at things from a U.S.-centric perspective
(rather than U.S. and European) and from a supplier or regulatory perspective;
this article embraces the laboratory user perspective.
The reference is:
Sandle, T. (2020) Historical
Milestones and Industry Drivers in the Development of Recombinant Lysate for
Bacterial Endotoxin Testing, American Pharmaceutical Review, at: https://www.americanpharmaceuticalreview.com/Featured-Articles/569887-Historical-Milestones-and-Industry-Drivers-in-the-Development-of-Recombinant-Lysate-for-Bacterial-Endotoxin-Testing/
Posted by Dr. Tim Sandle,
Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)