Figure 3.

Induction of (a) proliferation and (b) secretion of tumour necrosis factor-α (TNF-α), (c) interferon-γ (IFN-γ) and (d) interleukin-10 (IL-10) by pulmonary cells, isolated on the indicated days after primary Chlamydia pneumoniae infection from wild-type, CD8-depleted and nude mice, in response to in vitro stimulation with inactivated C. pneumoniae. In the late stage of infection (days 18–33), data from typically two different time-points are combined. In panel (d) the scale is one-tenth that of panels (b) and (c). The proliferation index was calculated as described in the Materials and methods. Cytokine secretion results are expressed as C. pneumoniae-induced cytokine secretion after subtraction of the background secretion. BD, below the detection limit; ND, not determined.