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Published on: October 21, 2013
Increased macrophage division in the synovial fluid of goats infected with caprine arthritis-encephalitis virus
1Department of Veterinary Microbiology and Pathology, Washington State University, Pullman 99164-7040.
Abstract:
Macrophages are a major component of the arthritic lesions induced by the lentivirus caprine arthritis-encephalitis virus (CAEV). Using autoradiography and the appearance of mitotic figures to detect dividing macrophages, we found that 2.1% +/- 0.2% of synovial fluid macrophages from uninfected goats are dividing and that after infection with CAEV the percentage increases three- to sixfold. The enhanced macrophage division was not associated with increased dividing of blood monoblasts. The amount of macrophage division correlated with two measures of arthritis: joint swelling and the number of synovial fluid macrophages. Induction of an immune response in the joints of CAEV-infected goats increased the number of dividing macrophages. The synovial fluid of infected animals was mitogenic for macrophages from infected animals in amounts that correlated with the amount of macrophage division occurring in the joints. Activated lymphocytes produced nondialyzable lymphokines mitogenic for macrophages from CAEV-infected goats but not from uninfected goats. These results suggest that in situ macrophage division contributes to the lesions induced by CAEV and that infection leads to greater responsiveness of macrophages to mitogenic factors produced by lymphocytes.
Insights
Caprine arthritis-encephalitis virus (CAEV) infection significantly increases macrophage division in joints, contributing to arthritis. Infected goats
Area of Science:
- Veterinary Medicine
- Immunology
- Virology
Background:
- Macrophages are key cells in the inflammatory lesions of caprine arthritis-encephalitis virus (CAEV) infection.
- The role of macrophage proliferation in CAEV-induced arthritis is not fully understood.
Purpose of the Study:
- To investigate the contribution of in situ macrophage division to CAEV-induced arthritis.
- To determine if CAEV infection alters macrophage responsiveness to mitogenic factors.
Main Methods:
- Autoradiography and mitotic figure analysis were used to quantify dividing macrophages in synovial fluid.
- Macrophage proliferation assays were performed using synovial fluid and lymphokines from infected and uninfected goats.
Main Results:
- CAEV infection increased synovial fluid macrophage division threefold to sixfold compared to uninfected goats.
- Macrophage division correlated with joint swelling and synovial fluid macrophage counts.
- Synovial fluid from infected goats was mitogenic for macrophages from infected goats, and activated lymphocytes produced mitogenic lymphokines.
Conclusions:
- In situ macrophage division is a significant factor in the pathogenesis of CAEV-induced arthritis.
- CAEV infection enhances macrophage sensitivity to lymphocyte-derived mitogenic factors, promoting disease progression.
