Human bocavirus 1 infection of CACO-2 cell line cultures

- HBoV1 replicates within 24 h in standard and differentiated Caco-2 cells.
- DNA is detected in attached cell and supernatant medium.
- Immunofluorescence tests evidences HBoV1 infection.
- DNA replication occurred but infectious progeny particles were not produced.
- The viral genome presents deleterious mutations at NS1 and VP1/VP2 regions.

Human bocavirus 1 (HBoV1) is a parvovirus associated with pneumonia in infants. It has been detected in different tissues, including colorectal tumors. In this study, we investigated whether Caco-2 cell line, derived from human colon cancer, can be utilized as a model for HBoV1 replication. We demonstrate HBoV1 replication in Caco-2 cultures supplemented with DEAE-dextran after inoculation with respiratory material from infected patients presenting with acute respiratory infection. A viral cycle of rapid development is displayed. However, in spite of HBoV1 DNA 4-fold increment in the supernatants and monolayers by day 1, evidencing that the system allows the virus genome replication after the entry occurred, infectious progeny particles were not produced. These results are consistent with an infection that is limited to a single growth cycle, which can be associated to mutations in the NS1 and VP1/VP2 regions of HBoV1 genome. Further research will contribute to fully elucidate these observations.