837
For this reason , the particle forming capacity of derivatives of the HIV - 1 group specific core antigen p55 gag was assayed and compared dependent on various expression systems : recombinant bacteria , vaccinia - and baculoviruses were established encoding the entire core protein p55 either in its authentic sequence or lacking the myristylation consensus signal .
 HIV - 1 group specific core antigen p55 gag, core protein p55
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 HIV - 1 group specific core antigen p55 gag, core protein p55