Fig. 1

Schematic illustration of methods for liquefying respiratory samples and comparative cytometric analysis of sputum leukocytes. A DTT reduces disulfide bonds cross-linking mucins in the matrix, and the enzymatic method uses endogenous catalase from sputum samples for producing oxygen bubbles, which mechanically disrupts cross-linked mucins. B The enzymatic liquefaction of sputum samples improves the single-cell analysis of sputum-resident leukocytes by flow cytometry, ensures the cell viability and holds their activation status unaltered