Typically, this can be done with a sterile falcon type cell strainer (comes in different mesh sizes) and a 50ml conical tube. We use an upside down plunger from a 1cc syringe to dissociate the tissue in the strainer. Good luck.
In our lab, we ofter seprate cell from spleen by grind on a piece of filter membrene than add into ficoll like separate peripheral blood, wich method is good to cell situation and for the next detection. Or you can use 1%RBC after grinding the spleen to get rid of red cells, which is not suitable for next culture, but is good and convienient for large quantity of cells.
We get LN cells by just simply grinding on the filter membrene too. But you should be careful, slowly and gently to avoiding mechenical damage to cells.