Synthetic human monoclonal antibodies toward staphylococcal enterotoxin B (SEB) protective against toxic shock syndrome.
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.
Integrated Biotherapeutics, Inc, Gaithersburg, Maryland 20878, USA.
Hatice
H
Karauzum
Gang
G
Chen
Laura
L
Abaandou
Mahta
M
Mahmoudieh
Atefeh R
AR
Boroun
Sergey
S
Shulenin
V Sathya
VS
Devi
Eric
E
Stavale
Kelly L
KL
Warfield
Larry
L
Zeitlin
Chad J
CJ
Roy
Sachdev S
SS
Sidhu
M Javad
MJ
Aman
D000818:Animals; D000911:Antibodies, Monoclonal / Q000235:genetics / Q000276:immunology / Q000494:pharmacology*; D000915:Antibody Affinity / Q000235:genetics; D004768:Enterotoxins / Q000037:antagonists & inhibitors* / Q000276:immunology / Q000633:toxicity; D057809:HEK293 Cells; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000235:genetics / Q000276:immunology / Q000494:pharmacology*; D007371:Interferon-gamma / Q000235:genetics / Q000276:immunology; D007376:Interleukin-2 / Q000235:genetics / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D012772:Shock, Septic / Q000139:chemically induced / Q000235:genetics / Q000276:immunology / Q000628:therapy*; D013997:Time Factors; D014026:Nicotiana / Q000235:genetics
D000911:Antibodies, Monoclonal; D004768:Enterotoxins; D007140:Immunoglobulin Fab Fragments; D007376:Interleukin-2; D011994:Recombinant Proteins; C031818:enterotoxin B, staphylococcal; D007371:Interferon-gamma