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Novel super-high affinity sheep monoclonal antibodies against CEA bind colon and lung adenocarcinoma
J Osborne1, P Harrison, R Butcher
1KS Biomedix Ltd., Guildford, Surrey, United Kingdom.
Abstract:
We have developed technology to create monoclonal antibodies (MAbs) using lymphocytes from immunized sheep. The affinities of these sheep monoclonal antibodies (SMA) can be several orders of magnitude higher than mouse MAbs. This paper reports the development and validation of a modified enzyme-linked immunoadsorbent assay (ELISA) method to select high-affinity antibodies of the desired specificity at the first screen. Using this method, we have isolated high affinity SMA to carcinoembryonic antigen (CEA), a marker of colon cancer. Comparisons of our novel SMA with mouse MAbs using the new ELISA and BIAcore technology (BIAcore AB, Stevenage, Herts, UK) have confirmed that we have made super-high affinity antibodies to CEA. One of these has a t(1/2) for dissociation of 8 days, which could provide a longer therapeutic window than is available with murine monoclonals currently being used in the clinic. This antibody has a specific tissue staining profile; it thus appears to be an excellent candidate for use in the clinic.
Insights
Researchers developed sheep monoclonal antibodies (SMA) with higher affinity than mouse MAbs for colon cancer marker CEA. A new ELISA method efficiently selects these high-affinity SMA for potential clinical use.
Area of Science:
- Immunology
- Biotechnology
- Oncology
Background:
- Murine monoclonal antibodies (MAbs) are crucial in cancer diagnostics and therapeutics.
- Existing MAbs often have limitations in affinity and therapeutic window.
- Sheep lymphocytes offer a promising source for developing high-affinity antibodies.
Purpose of the Study:
- To develop and validate a modified ELISA for selecting high-affinity sheep monoclonal antibodies (SMA).
- To isolate high-affinity SMA targeting carcinoembryonic antigen (CEA), a colon cancer marker.
- To compare the affinity and characteristics of novel SMA with existing mouse MAbs.
Main Methods:
- Immunization of sheep and isolation of lymphocytes for antibody production.
- Development and application of a modified enzyme-linked immunosorbent assay (ELISA) for antibody screening.
- Affinity and kinetic analysis using BIAcore technology.
Main Results:
- Successfully developed technology for producing high-affinity SMA from immunized sheep.
- Isolated high-affinity SMA targeting carcinoembryonic antigen (CEA).
- Demonstrated superior affinity of SMA compared to mouse MAbs, with one antibody exhibiting an 8-day dissociation half-life.
Conclusions:
- The developed ELISA method is effective for selecting high-affinity SMA.
- Novel SMA targeting CEA show potential for improved colon cancer diagnostics and therapeutics.
- The superior affinity and dissociation half-life of these SMA suggest a broader therapeutic window compared to current murine antibodies.