Ustekinumab drug level ELISA

Sample

Serum, Plasma (EDTA, Heparin)

Species Reactivity

Human

Detection Method

sELISA

Intended Use

The Ustekinumab ELISA has been especially developed for the quantitative analysis of free ustekinumab in serum and plasma samples.

Storage

The kit is shipped at ambient temperature (10-30°C) and should be stored at 2-8°C for long term storage. Keep away from heat or direct sunlight. The strips of microtiter plate are stable up to the expiry date of the kit in the broken, but tightly closed bag when stored at 2-8°C.

Precision

Intra-assay and inter-assay CVs < 30%

Sensitivity

The lowest detectable level (Lowest detection limit, LOD) that can be distinguished from the zero standard is 2.5 ng/mL
Functional sensitivity (Limit of quantification-LOQ): 3 ng/mL

General Description

Ustekinumab is a human immunoglobulin (Ig) G1 kappa monoclonal antibody directed against interleukin (IL)-12 and IL-23. It was generated via recombinant human IL-12 immunization of human Ig (hu-Ig) transgenic mice. It is a targeted biologic disease-modifying anti-rheumatic drug (bDMARDs) that is used in the management of various inflammatory conditions that involve the activation of IL-12 and IL-23 signalling pathways. Interleukin (IL)-12 and IL-23 are heterodimeric cytokines that evoke immune and inflammatory responses, such as natural killer cell activation and CD4+ T-cell differentiation and activation. The role of IL-12 and IL-23 were implicated in a variety of chronic inflammatory conditions, such as psoriasis and inflammatory bowel diseases. They modulate lymphocyte function, including T-helper (Th) 1 and Th17 cell subsets, as CD4+ T cells can differentiate into T-helper (Th) effector lineages based on the environment. Th cells can further activate the downstream pro-inflammatory mediators and transcription factors such as TNFα and IFNγ that drive innate and adaptive immunity. IL-12 and IL-23 share a common p40 subunit, paired with p35 and p19 subunits of IL-12 and IL-23, respectively. The antigen-binding fragment (Fab) of ustekinumab binds the D1 domain of the p40 subunit of IL-12 and IL-23 in a 1:1 ratio. This prevents IL-12 and IL-23 from binding to the IL-12Rβ1 receptor chain of IL-12 (IL-12Rβ1/β2) and IL-23 (IL12Rβ1/23R) receptor complexes on the surface of NK and T cells. Ustekinumab only binds to IL-12 and IL-23 that are unbound to IL-12Rβ1, so it is unlikely to initiate Fc effector functions, such as ADCC or CDC. Inhibition of the IL-12/23 signalling pathway leads to profound suppression of both the Th1 and Th17 cell lineage of cytokines and chemokines and their inflammatory pathways.