Anti-human EBI3 mAb (MT23A14), unconjugated

The IL-12 cytokine family

The IL-12 cytokine family consists of IL-12, IL-23, IL-27, IL-35, and IL-39. The existence of IL-39 in human remains, however, to be confirmed. The proteins are heterodimers of different subunits which are either unique or shared by several family members. IL-12 is a heterodimer, (p70), consisting of two covalently linked subunits, p35 and p40. The p40 subunit is shared with IL-23 which is a heterodimer of p40 and a unique p19 subunit. The p40 subunit also exists as a monomer and homodimer. The EBI3 subunit is shared with IL-27, IL-35, and IL-39.

Mabtech supplies monoclonal antibodies with defined subunit specificities to p40, p35, p19, p28, and EBI3. Since both IL-12 and IL-23 heterodimers contain the p40 subunit, capture immunoassays based on antibodies to p40 will detect both cytokines. Such assays can also detect p40 monomers and dimers. The EBI3 assays will detect IL-27, IL-35, and IL-39.

In our IL-12 and IL-23 assays, the same capture antibodies to p40 (MT86/221) are used. Different detection antibodies enable the detection of IL-12 (p70), IL-12/-23 (p40), and IL-23.

Application guide: mAbs to human IL-12, IL-23, IL-27 and EBI3

IL-12 products

Find out which analyte combinations we have evaluated in T cell FluoroSpot and which combinations are affected by capture effects or not. 

Co-stimulation with anti-CD28

Anti-CD28 mAb provides a co-stimulatory signal to antigen-specific responses by binding to CD28 on T cells. The addition of an anti-CD28 mAb to the cell culture enhances antigen-specific responses and can counteract capture effects. For example, the presence of IL-2 capture antibodies may result in reduced activation of T cells, as capturing of IL-2 decreases the amount of available IL-2 and thereby dampens the IL-2-mediated stimulation of T cells. The addition of anti-CD28 mAb restores IFN-γ responses (depicted in the below images). Further optimization may be necessary, depending on the cells and stimuli used. Too high concentrations of the anti-CD28 mAb may result in an elevation of non-specific cytokine secretion.

How to investigate capture effects

Our FluoroSpot Plus kits are evaluated for capture effects, and in studies of T cell responses we recommend co-stimulation with anti-CD28. With FluoroSpot Flex, it is possible to combine and build your own kit. For guidance look at our analyte combination table (above). Capture effects can be investigated by quantifying spot numbers in wells coated with single capture antibodies and compared to wells coated with a mixture of the capture antibodies. The compensatory effect of the anti-CD28 mAb may be assessed by comparing cells cultured with and without the anti-CD28 mAb.