Older mice are more susceptible to proteoglycan-induced arthritis (PGIA). Researchers writing in BioMed Central's open access journal Immunity & Ageing have shown, for the first time, that young mice are completely resistant, but become fully susceptible to the disease with age.
Tibor Glant, from Rush University Medical Center, Chicago, worked with a team of researchers to investigate the effects of immunological senescence on susceptibility to arthritis. He said, "Our results suggest that, while the young can effectively regulate their immune response to proteoglycan, in older mice these mechanisms are partially lost. This 'physiological' loss of control may lead to sustained activation of autoreactive T cells and auto-antibody production, directing the immune system against self antigen and culminating in joint inflammation in genetically susceptible animals".
The researchers conclude that complex age-related changes in interactions between T cells and antigen presenting cells, and reduced generation of regulatory T cells, may lead to impaired immune regulation and the development of autoimmune disease. Glant said, "Increasing incidence of rheumatoid arthritis with age has been repeatedly shown in the human population, hopefully this mouse model will go some way towards explaining why".