Use of the human colorectal adenocarcinoma (Caco-2) cell line for isolating respiratory viruses from nasopharyngeal aspirates.

The human colorectal adenocarcinoma-derived Caco-2 cell line was evaluated as a means isolating common respiratory viruses from nasopharyngeal aspirates for the diagnosis of respiratory diseases. One hundred eighty-nine direct immunofluorescence positive nasopharyngeal aspirates obtained from patients with various viral respiratory diseases were cultured in the presence of Caco-2 cells or the following conventional cell lines: LLC-MK2, MDCK, HEp-2, and A549. Caco-2 cell cultures effectively propagated the majority (84%) of the viruses present in nasopharyngeal aspirate samples compared with any positive cultures obtained using the panel cells (78%) or individual cell line MDCK (38%), HEp-2 (21%), LLC-MK2 (27%), or A549 (37%) cell lines. The differences against individual cell line were statistically significant (P = < 0.000001). Culture in Caco-2 cells resulted in the isolation of 85% (36/42) of viruses which were not cultivated in conventional cell lines. By contrast, 80% (24/30) of viruses not cultivated in Caco-2 cells were isolated using the conventional panel. The findings indicated that Caco-2 cells were sensitive to a wide range of viruses and can be used to culture a broad range of respiratory viruses.