8803
Using the [3H]thymidine proliferation assay , we determined reactivity to purified recombinant SSB ( rSSB ) in 20 patients with SS and 19 controls .
 purified recombinant SSB, rSSB
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:
 purified recombinant SSB, rSSB