Synthetic human monoclonal antibodies toward staphylococcal enterotoxin B (SEB) protective against toxic shock syndrome.

Abstract

Staphylococcal enterotoxin B (SEB) is a potent toxin that can cause toxic shock syndrome and act as a lethal and incapacitating agent when used as a bioweapon. There are currently no vaccines or immunotherapeutics available against this toxin. Using phage display technology, human antigen-binding fragments (Fabs) were selected against SEB, and proteins were produced in Escherichia coli cells and characterized for their binding affinity and their toxin neutralizing activity in vitro and in vivo. Highly protective Fabs were converted into full-length IgGs and produced in mammalian cells. Additionally, the production of anti-SEB antibodies was explored in the Nicotiana benthamiana plant expression system. Affinity maturation was performed to produce optimized lead anti-SEB antibody candidates with subnanomolar affinities. IgGs produced in N. benthamiana showed characteristics comparable with those of counterparts produced in mammalian cells. IgGs were tested for their therapeutic efficacy in the mouse toxic shock model using different challenge doses of SEB and a treatment with 200 μg of IgGs 1 h after SEB challenge. The lead candidates displayed full protection from lethal challenge over a wide range of SEB challenge doses. Furthermore, mice that were treated with anti-SEB IgG had significantly lower IFNγ and IL-2 levels in serum compared with mock-treated mice. In summary, these anti-SEB monoclonal antibodies represent excellent therapeutic candidates for further preclinical and clinical development.

• Authors: Hatice Karauzum, Gang Chen, Laura Abaandou, Mahta Mahmoudieh, Atefeh R Boroun, Sergey Shulenin, V Sathya Devi, Eric Stavale, Kelly L Warfield, Larry Zeitlin, Chad J Roy, Sachdev S Sidhu, M Javad Aman
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 287 Issue 30 Pg. 25203-15 (Jul 20 2012) ISSN: 1083-351X [Electronic] United States
• PMID: 22645125 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Antibodies, Monoclonal
• Enterotoxins
• Immunoglobulin Fab Fragments
• Interleukin-2
• Recombinant Proteins
• enterotoxin B, staphylococcal
• Interferon-gamma

Topics

• Animals
• Antibodies, Monoclonal (genetics, immunology, pharmacology)
• Antibody Affinity (genetics)
• Enterotoxins (antagonists & inhibitors, immunology, toxicity)
• HEK293 Cells
• Humans
• Immunoglobulin Fab Fragments (genetics, immunology, pharmacology)
• Interferon-gamma (genetics, immunology)
• Interleukin-2 (genetics, immunology)
• Mice
• Mice, Inbred BALB C
• Recombinant Proteins (genetics, immunology, pharmacology)
• Shock, Septic (chemically induced, genetics, immunology, therapy)
• Time Factors
• Nicotiana (genetics)