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Insulin-like growth factor-I (IGF-I) circulates in human serum as a 7 kDa peptide but analysis of IGF-I cDNAs predicts two pro-hormone precursors (proIGF-IA and proIGF-IB) with distinct C-terminal E domains. The function of these precursors, and the E peptides generated on cleavage to mature IGF-I, is unknown, largely because of a lack of tools for distinguishing precursors from constituent peptides. We used a synthetic Ea peptide to develop monoclonal antibodies (MAbs) which can recognize the carboxy-terminal sequence of proIGF-IA. These were characterized using proIGF-IA generated by transfected HEK293 cells. The anti-proIGF-IA MAbs immunoprecipitated two peptides (19--21 and 14 kDa) which were also recognized by MAbs to mature IGF-I. The proIGF-IA MAbs could also detect peptides of 9 and 4 kDa predicted to be Ea peptides. Treatment with N -glycosidase proved the 19--21 kDa and 9 kDa bands to be glycosylated proIGF-IA and Ea peptide respectively. Using these antibodies, we have identified proIGF-IA secreted from the IM9 B-lymphocyte cell line. This work paves the way for studies on proIGF-IA and Ea peptide regulation and function., (Copyright 2001 Harcourt Publishers Ltd.)

Two patients with acute respiratory failure requiring mechanical ventilation were found to have eosinophilic alveolitis on bronchoalveolar lavage and lung biopsy studies. Neither patient had evidence of lung infection or parasitic disease and both rapidly improved following treatment with corticosteroids. Lung eosinophilia in this setting is unusual, since the stress reaction that accompanies severe illness usually causes a rapid drop in circulating eosinophil levels. Eosinophilic alveolitis in such patients may be a useful clinical marker for non-infectious acute lung injury that is responsive to corticosteroid therapy.