25051
Among these virulence factors is the cysteine peptidase gingipain B ( RgpB ) , which is the major virulence factor secreted by the periodontopathogen Porphyromonas gingivalis that attacks host vasculature and defense proteins .
 cysteine
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 cysteine