scholarly journals Computational Construction of a Single-Chain Bi-Paratopic Antibody Allosterically Inhibiting TCR-Staphylococcal Enterotoxin B Binding

2021 ◽  
Vol 12 ◽  
Author(s):  
Ganggang Bai ◽  
Yanhong Ge ◽  
Yuhong Su ◽  
Shuo Chen ◽  
Xingcheng Zeng ◽  
...  
Keyword(s):  
Mhc Class Ii ◽  
Bispecific Antibody ◽  
Staphylococcal Enterotoxin ◽  
Staphylococcal Enterotoxin B ◽  
Single Chain ◽  
Mhc Ii ◽  
Enterotoxin B ◽  
Dynamics Simulations ◽  
Class Ii Antigen ◽  
Tcr Activation

Staphylococcal enterotoxin B (SEB) simultaneously crosslinks MHC class II antigen and TCR, promoting proliferation of T cells and releasing a large number of toxic cytokines. In this report, we computationally examined the possibility of using a single-chain biparatopic bispecific antibody to target SEB and prevent TCR binding. The design was inspired by the observation that mixing two anti-SEB antibodies 14G8 and 6D3 can block SEB-TCR activation, and we used 14G8-6D3-SEB tertiary crystal structure as a template. Twelve simulation systems were constructed to systematically examine the effects of the designed bispecific scFV MB102a, including isolated SEB, MB102a with different linkers, MB102a-SEB complex, MB102a-SEB-TCRβ complex, MB102a-SEB-TCR-MHC II complex, and MB102a-SEB-MHC II. Our all atom molecular dynamics simulations (total 18,900 ns) confirmed that the designed single-chain bispecific antibody may allosterically prevent SEB-TCRβ chain binding and inhibit SEB-TCR-MHC II formation. Subsequent analysis indicated that the binding of scFV to SEB correlates with SEB-TCR binding site motion and weakens SEB-TCR interactions.

scholarly journals Potent Neutralization of Staphylococcal Enterotoxin B by Synergistic Action of Chimeric Antibodies

2010 ◽  
Vol 78 (6) ◽  
pp. 2801-2811 ◽  
Author(s):  
Mulualem E. Tilahun ◽  
Govindarajan Rajagopalan ◽  
Nalini Shah-Mahoney ◽  
Rebecca G. Lawlor ◽  
Ashenafi Y. Tilahun ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Population ◽  
T Cell Activation ◽  
Mammalian Cells ◽  
Cell Activation ◽  
Staphylococcal Enterotoxin ◽  
Staphylococcal Enterotoxin B ◽  
Mhc Ii ◽  
Genes Encoding ◽  
Enterotoxin B

ABSTRACT Staphylococcal enterotoxin B (SEB), a shock-inducing exotoxin synthesized by Staphylococcus aureus, is an important cause of food poisoning and is a class B bioterrorism agent. SEB mediates antigen-independent activation of a major subset of the T-cell population by cross-linking T-cell receptors (TCRs) with class II major histocompatibility complex (MHC-II) molecules of antigen-presenting cells, resulting in the induction of antigen independent proliferation and cytokine secretion by a significant fraction of the T-cell population. Neutralizing antibodies inhibit SEB-mediated T-cell activation by blocking the toxin's interaction with the TCR or MHC-II and provide protection against the debilitating effects of this superantigen. We derived and searched a set of monoclonal mouse anti-SEB antibodies to identify neutralizing anti-SEB antibodies that bind to different sites on the toxin. A pair of non-cross-reactive, neutralizing anti-SEB monoclonal antibodies (MAbs) was found, and a combination of these antibodies inhibited SEB-induced T-cell proliferation in a synergistic rather than merely additive manner. In order to engineer antibodies more suitable than mouse MAbs for use in humans, the genes encoding the VL and VH gene segments of a synergistically acting pair of mouse MAbs were grafted, respectively, onto genes encoding the constant regions of human Igκ and human IgG1, transfected into mammalian cells, and used to generate chimeric versions of these antibodies that had affinity and neutralization profiles essentially identical to their mouse counterparts. When tested in cultures of human peripheral blood mononuclear cells or splenocytes derived from HLA-DR3 transgenic mice, the chimeric human-mouse antibodies synergistically neutralized SEB-induced T-cell activation and cytokine production.

scholarly journals Structural basis for the neutralization and specificity of Staphylococcal enterotoxin B against its MHC Class II binding site

mAbs ◽  
2013 ◽  
Vol 6 (1) ◽  
pp. 119-129 ◽  
Author(s):  
Tian Xia ◽  
Shuaiyi Liang ◽  
Huajing Wang ◽  
Shi Hu ◽  
Yuna Sun ◽  
...  
Keyword(s):  
Binding Site ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Staphylococcal Enterotoxin ◽  
Structural Basis ◽  
Staphylococcal Enterotoxin B ◽  
Enterotoxin B

scholarly journals The toxicity of staphylococcal enterotoxin B in mice is mediated by T cells.

1990 ◽  
Vol 171 (2) ◽  
pp. 455-464 ◽  
Author(s):  
P Marrack ◽  
M Blackman ◽  
E Kushnir ◽  
J Kappler
Keyword(s):  
Weight Loss ◽  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Cell Function ◽  
Class Ii ◽  
Staphylococcal Enterotoxin ◽  
Staphylococcal Enterotoxin B ◽  
Rapid Weight Loss ◽  
Enterotoxin B

Staphylococcal enterotoxin B (SEB) has been shown in the past to be a potent T cell stimulant in mouse or man. The toxin acts as a superantigen that is, it binds to class II MHC proteins and, as such a complex, stimulates T cells bearing particular V beta s as part of their receptors. The toxin also has several pathological effects, causing, in mice, rapid weight loss, thymus atrophy, immunosuppression, and, at high doses, death. The data in this paper show that at least one of these effects, weight loss, is T cell mediated. Staphylococcal enterotoxin-mediated weight loss is MHC dependent, and is almost absent in animals expressing MHC class II molecules, which, complexed with SEB, are poor T cell stimulants. Also, mice that lack T cell function, genetically or because of cyclosporin A treatment, lose no or less weight than controls in response to SEB. Finally, animals bred such that they express few T cells bearing V beta s with which SEB can interact lose much less weight in response to the toxin than littermate controls that have higher numbers of reactive T cells. It is therefore suggested that the pathological effects of the staphylococcal, T cell-stimulating toxins in mouse and man may be partially or wholly the consequence of massive T cell stimulation.

scholarly journals Construction of a Single-Chain Variable-Fragment Antibody against the Superantigen Staphylococcal Enterotoxin B

2010 ◽  
Vol 76 (24) ◽  
pp. 8184-8191 ◽  
Author(s):  
Pawan Kumar Singh ◽  
Ranu Agrawal ◽  
Dev Vrat Kamboj ◽  
Garima Gupta ◽  
M. Boopathi ◽  
...  
Keyword(s):  
Phage Display ◽  
Staphylococcal Enterotoxin ◽  
Scfv Antibody ◽  
Affinity Constant ◽  
Enzyme Linked Immunosorbent Assay ◽  
Staphylococcal Enterotoxin B ◽  
Single Chain Variable Fragment ◽  
Single Chain ◽  
High Affinity ◽  
Enterotoxin B

ABSTRACT Staphylococcal food poisoning (SFP) is one of the most prevalent causes of food-borne illness throughout the world. SFP is caused by 21 different types of staphylococcal enterotoxins produced by Staphylococcus aureus. Among these, staphylococcal enterotoxin B (SEB) is the most potent toxin and is a listed biological warfare (BW) agent. Therefore, development of immunological reagents for detection of SEB is of the utmost importance. High-affinity and specific monoclonal antibodies are being used for detection of SEB, but hybridoma clones tend to lose their antibody-secreting ability over time. This problem can be overcome by the use of recombinant antibodies produced in a bacterial system. In the present investigation, genes from a hybridoma clone encoding monoclonal antibody against SEB were immortalized using antibody phage display technology. A murine phage display library containing single-chain variable-fragment (ScFv) antibody genes was constructed in a pCANTAB 5E phagemid vector. Phage particles displaying ScFv were rescued by reinfection of helper phage followed by four rounds of biopanning for selection of SEB binding ScFv antibody fragments by using phage enzyme-linked immunosorbent assay (ELISA). Soluble SEB-ScFv antibodies were characterized from one of the clones showing high affinity for SEB. The anti-SEB ScFv antibody was highly specific, and its affinity constant was 3.16 nM as determined by surface plasmon resonance (SPR). These results demonstrate that the recombinant antibody constructed by immortalizing the antibody genes from a hybridoma clone is useful for immunodetection of SEB.

T cell activation and retargeting using staphylococcal enterotoxin B and bispecific antibody: An effective in vivo antitumor strategy

1997 ◽  
Vol 45 (3-4) ◽  
pp. 180-183 ◽  
Author(s):  
Lewis E. Porter ◽  
Heidi Nelson ◽  
I. Ethem Gecim ◽  
David C. Rice ◽  
Claude Thibault ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Bispecific Antibody ◽  
Staphylococcal Enterotoxin ◽  
Staphylococcal Enterotoxin B ◽  
Enterotoxin B

scholarly journals Mutations defining functional regions of the superantigen staphylococcal enterotoxin B.

1992 ◽  
Vol 175 (2) ◽  
pp. 387-396 ◽  
Author(s):  
J W Kappler ◽  
A Herman ◽  
J Clements ◽  
P Marrack
Keyword(s):  
T Cell ◽  
Mhc Class Ii ◽  
Cell Receptor ◽  
Class Ii ◽  
Staphylococcal Enterotoxin ◽  
Staphylococcal Enterotoxin B ◽  
Rapid Weight Loss ◽  
Functional Regions ◽  
T Cell Stimulation ◽  
Enterotoxin B

Staphylococcal enterotoxin B (SEB) is both a superantigen and toxin. As a superantigen, SEB can bind to major histocompatibility complex (MHC) class II molecules to form a ligand for alpha/beta T cell receptors bearing particular V beta elements. As a toxin, SEB causes rapid weight loss in mice sometimes leading to death. We show here that both of these functions map to the NH2-terminal portion of the toxin. Three regions were identified: one important in MHC class II binding, one in T cell recognition, and one in both functions. These results support the conclusion that the toxicity of SEB is related to massive T cell stimulation and release of cytokine mediators and show that the residues interacting with MHC and the T cell receptor are intertwined.

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