In vitro Susceptibility of Human Cell Lines Infection by Bovine Leukemia Virus

Abstract

Evidence of the presence of bovine leukemia virus (BLV) in human beings and its association with breast cancer has been published in the literature, proposing it as a zoonotic infection. However, not enough evidence exists about transmission pathways nor biological mechanisms in human beings. This study was aimed at gathering experimental evidence about susceptibility of human cell lines to BLV infection. Malignant and non-malignant human cell lines were co-cultured with BLV-infected FLK cells using a cell-to-cell model of infection. Infected human cell lines were harvested and cultured for 3 to 6 months to determine stability of infection. BLV detection was performed through liquid-phase PCR and visualized through in situ PCR. Seven out of nine cell lines were susceptible to BLV infection as determined by at least one positive liquid-phase PCR result in the 3-month culture period. iSLK and MCF7 cell lines were able to produce a stable infection throughout the 3-month period, with both cytoplasmic and/or nuclear BLV-DNA visualized by IS-PCR. Our results support experimental evidence of BLV infection in humans by demonstrating the susceptibility of human cells to BLV infection, supporting the hypothesis of a natural transmission from cattle to humans.

Different Mutation Tolerance of Lentiviral (HIV-1) and Deltaretroviral (BLV and HTLV) Protease Precursors

“…The bovine leukemia virus (BLV) is also a member of the Deltaretrovirus genus; it is closely related to HTLV-1/2 and it is the causative agent of enzootic bovine leucosis, a disease characterized by the occurrence of the clonal lymphoid tumor of B-cell origin [2]. Humans are also exposed to the BLV infection; the human cells may be susceptible to BLV due to the transmission of the virus via consumption of infected foodstuffs [3,4], but the correlation of BLV with the development of diseases such as breast cancer is still controversial [5]. BLV is considered to be a valuable model system for understanding the HTLVs.…”