Figure 3.
SP-D modulation of antigen presentation of E. coli HB101-OVA by lung antigen-presenting cells and BMDCs. (A) Low-density CD11c-positive lung cells (squares) or BMDCs (circles) were incubated with E. coli expressing OVA in the presence (filled symbols) or absence (open symbols) of 8 μg SP-D/ml for 3.5 h at 37°C. The cells were washed and incubated with OVA258–276−specific T-cell hybridomas for 24 h, and the amount of IL-2 in the supernatant was measured by ELISA. (B) Low-density CD11c-positive lung cells from mice exposed to LPS 36 h in advance or nonstimulated BMDCs incubated with E. coli HB101-OVA and T-cell hybridomas, as described in (A). Data are means (± SE) of duplicate or triplicate analyses, and reflect a representative experiment from a set of at least three independent experiments. * Significant difference in the absence or presence of SP-D with P < 0.05, estimated using Student's t-test. (C) Summary of the effect of SP-D on the antigen presentation by mouse lung antigen-presenting cells (LAPCs), low-density density CD11c cells from mice exposed to LPS 36 h in advance (LAPCs + LPS), and BMDCs. Ratio in parenthesis are the number of antigen-presenting cells versus the number of E. coli HB101-OVA (the ratio at which maximal IL-2 signal was observed in the absence SP-D).