Critical Role of Dendritic Cells in Mouse Mammary Tumor Virus In Vivo Infection

Abstract

Mouse mammary tumor virus (MMTV) is a milk-transmitted betaretrovirus that causes

Expression of Murine APOBEC3 Alleles in Different Mouse Strains and Their Effect on Mouse Mammary Tumor Virus Infection

“…Control cells were treated with 3 mg/ml of the reverse transcriptase inhibitor azidothymidine (AZT; Sigma, Inc.) at 37°C for 2 h prior to infection. DCs and MEFs were infected by the spinoculation method as previously described (12). The cells were cultured for 24 h after infection prior to harvesting.…”

“…DNA was isolated from the draining lymph nodes of infected mice by using DNeasy (Qiagen, Inc.) according to the manufacturer's instructions. DNA was used for real-time quantitative PCR (RT-qPCR) to detect integrated proviruses, as previously described, using primers specific to the MMTV(RIII) long terminal repeat and were normalized to GAPDH (glyceraldehyde-3-phosphate dehydrogenase) (12,28). In some experiments, fluorescence-activated cell sorter (FACS) analysis was used to detect infection of DCs, MEFs, and mA3-transfected 293T-mTfR1 cells by pGR102ES virus; data are presented as percentages of GFP-positive cells.…”

A Novel Block to Mouse Mammary Tumor Virus Infection of Lymphocytes in B10.BR Mice

“…Dilutions of purified virus were tested for B-cell and Sagmediated T-cell activation in C3H/HeN mice in vivo, and the highest dilution giving the maximum Sag-dependent stimulation (usually 1:200) was used for subsequent experiments. All virus preparations were also tested for lipopolysaccharide contamination, as previously described (7,10,36).…”

“…MMTV first infects APCs in Peyer's patches, including dendritic and B cells (3,7,10,28,42). The infected APCs then present Sag to cognate CD4 ϩ T cells, causing their stimulation and subsequent bystander B-cell activation that is dependent on CD40-CD40L interactions (9).…”

“…Virus infection spreads to other lymphoid organs, and B, T, and dendritic cells become MMTV infected (13,28,42). T and B cells, as well as DCs, are capable of producing infectious virus (10,13), and infected lymphoid cells are required for virus spread within the mammary gland (18). Thus, MMTV represents a model system for the study of milk-borne retroviruses, such as HIV and human T-cell leukemia virus type 1, that initially infect lymphocytes in the gut mucosa (39,40,45).…”