Upper respiratory tract epithelial cells as a component of local immunity against influenza

A conjugate of influenza virus and erythrocytes was used to detect and quantitatively determine the occurrence of respiratory epithelial cells carrying surface-associated antibody. The method was specific since uncoated erythrocytes, or erythrocytes coated with heterologous virus failed to attach. Epithelial cells carrying surface-bound anti-influenza virus antibodies (Ab) were found in the upper respiratory tract of 23 influenza patients and 117 healthy persons during and after an influenza A(H1N1) outbreak, and in 13 volunteers immunized with killed influenza A(H1N1) vaccine. Furthermore, the appearance of Ab-carrying cells correlated with that of circulating and secretory Ab in washings from the same individuals. The results suggest that the respiratory epithelial cells play an important role in the development and function of local anti-influenza immunity.