FIG. 4.

SP-B mRNA expression in the lungs of P. carinii-infected mice. Steady-state levels of SP-B mRNA were measured in the lung by S1 nuclease protection assays. (A) mRNA levels in reconstituted (light gray) and nonreconstituted (dark gray) P. carinii-infected SCID mice at 9 weeks post exposure (W.P.E.). Reconstituted mice were examined at 12 DPR during the peak inflammatory phase. P. carinii-free SCID mice were used as normal controls. (B) SP-B levels during the progression of P. carinii infection in nonreconstituted SCID mice. Again, P. carinii-free SCID mice were used as normal controls. (C) SP-B levels in normal (control), CD4⁺-depleted, and CD4⁺- and CD8⁺-depleted mice at 34 days after inoculation with P. carinii. In all experiments SP-B mRNA levels were normalized to murine ribosomal protein L32 and then expressed as percentages of the control. Each value is the mean ± 1 standard error for four mice. ∗, experimental groups that are statistically different (P < 0.05) from the control group.