Identification of human cytomegalovirus phosphoprotein 65 in C57BL/6 and BXSB mice as a potential trigger of systemic lupus erythematosus related serum markers

ABSTRACT

Objective: To investigate the potential role of human cytomegalovirus lower matrix phosphoprotein 65 (HCMV-pp65) in murine systemic lupus erythematosus (SLE). Methods: The prokaryotic plasmid pET-28b-pp65 was constructed to express the HCMVpp65 protein. BXSB mice and C57BL/6 mice were inoculated with pp65 eukaryotic plasmid pcDNA3.0-pp65 intramuscularly 5 times at 2-week intervals, and then the blood of the mice was subsequently collected via the retro-orbital vein. Indirect ELISAs were used to evaluate the concentration of anti-pp65 immunoglobulin G, anti-double-stranded DNA and antinuclear antibodies. Interleukin-1β and tumor necrosis factor-α were also determined by competitive ELISA. At the same time, 3 major SLE-related circulating microRNAs were examined by quantitative RT-PCR. Results: The early production of autoantibodies was observed in pp65-immunized male BXSB as well as C57BL/6 mice. Overexpression of interleukin-1β and tumor necrosis factor-α were detected in pp65-immunized male BXSB mice. Quantitative RT-PCR analyses showed that three SLE related microRNAs (microRNA-126, microRNA-125a, and microRNA-146a) were downregulated in peripheral blood mononuclear cells of pp65-immunized mice. Conclusions: Our findings indicate that HCMV-pp65 immunization strongly triggers the development and progression of SLE-like disease in both BXSB and C57BL/6 mice, which indicates that the immune responses induced by HCMV-pp65 may be involved in the development of SLE.