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Functional Assays

Toxin neutralization assays (TNA) evaluate candidate compound’s ability to protect against cytotoxic effects of toxins.

Neutralization of toxin can be measured in vitro by monitoring the reduction in SAg induced interferon-gamma production. IBT Bioservices offers toxin neutralization assays for Staphylococcal Enterotoxin A (SEA), Staphylococcal Enterotoxin B (SEB), Staphylococcal Enterotoxin C (SEC)and TSST-1. Additionally, as part of our product line we offer SEK expressed in E. coli that can be used a control for ELISAs, Westerns as well as a mitogen or to activate cytokines in PBMC. Hemolytic toxin neutralization assays exploit hemolytic activity of toxin to provide rapid/sensitive test for neutralization against Hla and non-canonical leucocidin pairs. Leucocidins act as synergistic pairs to induce damage of monocytes, macrophages, and neutrophils. Gamma-hemolysins also act synergistically but affect both leukocytes and red blood cells.

See table below for the functional assays we currently offer.
Assay Type Antigen Model Details
Hemagglutinin Inhibition Assay H1N1, H3N2, H5N1, H7N9, H10N8
Hemolytic Toxin Neutralization Assay Alpha hemolysin
Non-canonical leukocidin pairs
Leukocidin Toxin Neutralization Assay PVL Luk S/Luk F
Luk ED
Hlg AB
Hlg CB
Superantigen Toxin Neutralization Assay Staphylococcal Enterotoxin A
Staphylococcal Enterotoxin B
Staphylococcal Enterotoxin C
Filovirus GP VSV-pseudotyped Assay Ebola
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Fig. 1 Survival after challenge with INFV H1N1 A/Pert/261/2009 (Tamiflu-resistant strain). Inoculum 1xLD90=1.0E+05 PFU/mouse
Survival after challenge with INFV H1N1 A/Pert/261/2009 (Tamiflu-resistant strain) 1.0E+05 PFU/mouse
Survival and weight change in BALB/c mice challenged with INFV A/ Texas/36/91 (H1N1) and treated with antiviral Osletamivir Phosphate (Tamiflu)
Lung viral load and Survival (30 % weight loss cut-off) in BALB/c mice challenged with INFV H3N2 A/HK/1/68.

Alpha (UK) – B. 1.1.7 / 501Y.V1

amino acid mutations: del69–70 HV, del144 Y, N501Y, A570D, D614G, P681H, T761I, S982A, D1118H

Beta (South Africa) – B.1.351

amino acid mutations: K417N, E484K, N501Y, D614G, A701V

Gamma (Brazil) – P.1

amino acid mutations: L18F, T20N, P26S, D138Y, R190S, K417T, E484K, N501Y, D614G, H655Y, T1027I

Epsilon (Ca, USA) B.1.427

amino acid mutations: L452R, D614G

SARS-CoV-2 Parental Strain Wild Type (Wuhan)
SARS-CoV-2 D614G Variant

amino acid mutations: D614G

Epsilon (Ca, USA) B.1.429

amino acid mutations: S13I, W152C, L452R, D614G

SARS-CoV-2 Delta Variant

amino acid mutations: L452R, E484Q

Wishing You a Happy Thanskgiving!

In observance of Thanksgiving our offices will be closed Thursday November 24th through Sunday November 27th. We will resume normal business hours Monday November 28th. Please excuse any delayed responses during this period.

We look forward to assisting you with all your preclinical product and testing needs after the holiday. Happy Thanksgiving!

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