While incubation of PBMC with anti-CD3ε or the anti-CD28 agonist antibody TGN1412 antibodies resulted in robust cytokine production for a number of cytokines, including those associated with cytokine release syndrome (CRS) (TNFα, IL-6, IL-2, IFNγ, and IL-1β), incubation of donor PBMC with LY3300054 did not result in significant levels of cytokine release for any of the evaluated cytokines over a broad range of concentrations from 0.003 to100 μg/ml (Additional file 1: Figure S5). Here, IL6 is linked to congenital rubella syndrome.