Abstract
We examined doses and time of administration of lipopolysaccharide (LPS) which activates innate immunity via the Toll-like receptor 4. It has also been considered that LPS modifies the adaptive immunity response on mouse collagen-induced arthritis (CIA). DBA/1J male mice were immunized 200 μg of bovine type II collagen emulsified in CFA and boosted 21 days later. A single i.p. injection of LPS at doses of 4 or 40 μg/body was delivered on day 28. Freshly isolated peripheral leukocytes from intact, CIA, and CIA-LPS mice on day 35 and 42 were stained with mAbs and counted by FACSCalibur (BD Biosciences). The severity of visual scoring of CIA-LPS was slightly higher than that of CIA. On day 35, compared with CIA, CIA-LPS did not show the leukocyte number increment, and the proportion of granulocyte/lymphocyte increased. The percentage and number of CD11b/Ly6G positive neutrophils increased as same level as those in CIA. The number of CD19 positive (B) cells and CD3 positive (T) cells were significantly decreased. Among T cell subpopulations, the percentage of CD4 positive cells was significantly decreased. As to a dose, 4μg/body administrated mice showed the decrease on visual scoring variability within experiments. At a dose of 40 μg/body, the exacerbation of body condition including body weight loss was marked. These findings indicate that the relative increase of granulocyte percentage might be an essential factor that exacerbates joint inflammation, and the administration of 4 μg/body will be recommended to enhance CIA. [Jpn J Physiol 54 Suppl:S248 (2004)]
