Clara cell 10 kilodalton protein (CC10), the predominant product from nonciliated cells in the epithelial lining of bronchioles (Clara cells), has been shown to have immunomodulatory and anti-inflammatory activity, and may play roles in controlling inflammation in the airway. This study was designed to examine immunohistochemical expression of CC10 in epithelial cells in small airways (perimeter < 6 mm) of asthmatic and control nonsmokers who underwent lung resection because of peripheral lung carcinoma and to compare CC10-positive epithelial cell proportions with numbers of inflammatory cells in small airways of asthmatics. Significantly decreased proportions of CC10-positive epithelial cells and significantly increased numbers of T cells, activated eosinophils, and mast cells in small airways of asthmatics were found compared with those of control subjects. CC10-positive epithelial cell proportions inversely correlated with numbers of T cells and mast cells in small airways of asthmatics. Decreases of CC10-producing cells may give an accelerating cause for further aggravation of inflammatory responses in chronic asthma.

Clara cell 10-kDa protein (CC10), the predominant product from nonciliated cells in the epithelial lining of bronchioles (Clara cells), has been shown to have immunomodulatory and antiinflammatory activity and may play a role in controlling airway inflammation. This study was designed to measure serum CC10 concentrations in healthy and asthmatic nonsmokers. Serum CC10 concentrations in asthmatic nonsmokers were significantly lower than in healthy nonsmokers. Asthmatic patients with a long duration of the disease (≥10 years) had significantly lower serum CC10 levels than those with a short duration of the disease (<10 years). There was no significant difference in serum CC10 levels in asthmatic patients between the time of the asthmatic attack and the stable condition. Serum CC10 levels may reflect decreased production of CC10 caused by remodeling of the small airways in asthma.

Human protein 1/Clara cell Mr 10,000 protein consists of two identical subunits of seventy amino acid residues each. In the present study, eight clones of monoclonal antibodies against native protein 1 were prepared and their respective epitopes were immunochemically and immunohistochemically characterized using native protein 1, truncated recombinant protein 1 and synthesized peptides. Among the clones, three designated as TY-5, TY-7 and TY-8 recognized amino acid residues 7-16, residues 19-28, and residues 39-46, respectively, all of which comprise the hydrophobic cavity of protein 1, possibly associated with chemical binding function. With the exception of TY-4, the remaining clones recognized residues 61-68 which are exposed to solvent. The epitope of TY-4 remains undetermined. Proper selection and combination of clones and recombinant protein 1 may be useful for fundamental and clinical studies of protein 1.

A constitutive isotype of serum amyloid A (SAA4) is present mostly in high density lipoprotein (HDL) and a little in other lipoproteins. In this study, we developed an automated method for measuring SAA4 concentration in serum by kinetic nephelometry of anti-SAA4 antibody-coated latex agglutination. Rabbit antibodies generated by immunization of recombinant SAA4 were found to have no apparent reactivity with acute phase SAA. The values determined by this method and by the previous enzyme immunoassay showed good agreement (r = 0.862). Serum SAA4 values of 26 healthy adults ranged from 37-109 mg/L (mean; 62 mg/L). Their SAA4 concentrations were not significantly related with those of apolipoprotein A-I, A-II, B, C-II, C-III or E. Also, SAA4 did not correlate with cholesterol in preparation after removal of very low density lipoprotein and low density lipoprotein. These suggest the unique behavior of SAA4 in lipoprotein metabolism, while what contributes to variation of SAA4 levels in serum, especially in HDL, remains to be clarified.