Spleen lymphocyte kinetics in mice under normal and inflammatory conditions: an application of the transgenic mouse expressing beta-galactosidase (ROSA 26).

The purpose of this study was to develop a method for the measurement of the cell kinetics of spleen lymphocytes using the ROSA 26 transgenic mouse ubiquitously expressing beta-galactosidase (beta-gal). Spleen lymphocytes were isolated from ROSA 26 mice and intravenously inoculated into C57BL/6 mice under normal conditions and inflammatory conditions following lipopolysaccharide (LPS) treatment. Spleen lymphocyte accumulation in tissues was determined as a measurement of beta-gal activity. Spleen lymphocytes isolated from ROSA 26 mice have beta-gal activities of 1.45 x 10(-4) pg per cell. A good correlation between beta-gal activities and cell numbers was obtained (r2 = 0.999) over the range 1 x 10(3) to 1 x 10(7) cells, corresponding to 70 fg to 350 pg beta-gal activity. Spleen lymphocytes (4 x 10(7) cells) were intravenously inoculated into normal mice and subsequently each tissue was isolated and the corresponding beta-gal activity measured. Spleen lymphocyte accumulation was relatively high .in the spleen and lymph nodes. The accumulated spleen lymphocyte cell number was 1.39 x 10(7) cells/g spleen and 5.45 x 10(7) cells/g lymph node 1 h and 6h after inoculation, respectively, and this remained constant up to 24h. In the lung, lymphocyte accumulation was 3.98 x 10(7) cells/g tissue 10 min after inoculation then gradually fell to 7.09 x 10(5) cells/g tissue after 24h. In addition, the femoral muscle following intramuscular injection of LPS showed a high accumulation of spleen lymphocytes, whereas the untreated and contralateral femoral muscle had the same level as the background. In conclusion, spleen lymphocytes isolated from ROSA 26 mice can be used to measure beta-gal activity and the sensitivity is relatively high over the 70 fg to 350 pg range. This suggests that cells isolated from the ROSA 26 mouse can be applied to the study of cell kinetics.