Collagenase digestion down-regulates the density of CD27 on lymphocytes.

Collagenases are widely used for tissue digestion in experiments due to their potent hydrolysis of connective tissue. CD27, also known as tumor necrosis factor receptor superfamily 7 (TNFRSF7), is limited to be expressed on the cells of the lymphoid lineage. In our preliminary research, we found that CD27 on NK cells was almost disappeared with the digestion of type I collagenase for 90min. This phenomenon suggests that the process of tissue digestion may affect the density of CD27 on cells. In order to verify this, the lungs of mice were digested with types I and IV collagenase or grinded, respectively. The percentage of CD27(+) cells and the density of CD27 on cells were assayed by flow cytometry. The data presented that the percentage of CD27(+) cells and the density of CD27 on lymphocytes gradually decreased with the time of digestion with type I or IV collagenase. We also detected that the density of CD11b on NK cells was not affected by collagenase digestion. Collectively, the findings of the present study suggest that the collagenase digestion has a selective effect on the density of molecules on cells.