Figure 3.

Effect of interleukin (IL)-21 on cytokine and chemokine production by Mycobacterium tuberculosis (Mtb)-stimulated monocytes in the presence of natural killer (NK) cells. Freshly isolated monocytes from 6 latent tuberculosis infection (LTBI)⁺ individuals were cultured with CD3-CD56⁺ cells in the presence or absence of γ-Mtb as mentioned under Methods. Few cells were cultured with recombinant IL-21. After 48 hours, culture supernatants were collected, and (A) IL-1β, (B) macrophage-inflammatory protein (MIP)-1β, (C) IL-10, and (D) interfereon (IFN)- γ production were measured by enzyme-linked immunosorbent assay. The mean values, standard errors, and P values are shown.