Serial evaluation of absolute spleen cell numbers in Lewis lung tumor-bearing mice

Subcutaneous (sc) transposition of the spleen followed by fine needle biopsies (FNB) from the organ allows the evaluation of relative numbers of splenic cells in Lewis lung tumor-bearing mice. Absolute cell numbers (N) can be calculated when the aspirated cells are weighed on a precision balance (m) and counted (c) after resuspension in a defined volume (v): N = C X V/m X M. The weight from the whole spleen (M) is derived from a calibration curve. Splenic nucleated cells and their subsets--as determined by the use of monoclonal antibodies--can thus probably be evaluated with a degree of accuracy which was not possible before. Shifts of splenic cells from and to the organ can be monitored.