1856
The effect of a liposomal formulation of methylprednisolone ( MPL ) on the inhibition of lymphocyte proliferation in spleen cells was investigated following IV dosing in rats .
 spleen cells
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 spleen cells