11533
Vector stocks containing envelope proteins from three different SIVmac clones , namely , SIVmac239 ( T - lymphocyte tropic [ T - tropic ] ) , SIVmac316 ( macrophage tropic [ M - tropic ] ) , and SIVmac1A11 ( dualtropic ) , were tested .
 envelope proteins
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 envelope proteins