Figure 8.

SOCS secretion in the lung in vivo is regulated by immunomodulatory substances and dysregulated in association with cigarette smoking. (A) Mice (three per group) were subjected to intrapulmonary administration of 50 µl saline alone or saline containing 15 µg PGE₂ and/or LPS. BALF was harvested 3 h later, pooled, concentrated, and subjected to WB analysis for SOCS3. (B) BALF from never smokers or healthy current smokers (n = 4 subjects per group) was concentrated and subjected to WB analysis for SOCS3 and SOCS1; results from three subjects per group are depicted, with each lane representing an individual subject (top); after densitometric analysis of blots from all four subjects per group, SOCS levels in BALF of smokers was expressed as a percentage of that in never smokers (bottom, left). SOCS3 levels were also determined by ELISA of sonicated BALF in n = 7 subjects per group (bottom, right); the mean level in never smokers was 0.26 ± 0.12 pg/µg protein, and that in smokers was expressed as a percentage of the never-smoker level. Error bars indicate SE. (C) Mice were subjected or not to 2 h/d of cigarette smoke for 3 or 7 d, and BALF from at least three mice in each group (as indicated by the individual lanes) was subjected to WB analysis for SOCS3; data at the bottom represent mean ± SE arbitrary densitometric units. *, P < 0.05 versus human never smokers (B) or unexposed mice (C). The blot shown is representative of two experiments (A), or the data are the mean from the number of human subjects (B) or mice (C) indicated.