831
In two separate studies , specimens of saliva from 57 individuals over the age of 65 years ( mean age , 76 . 7 years ) and 37 persons under the age of 40 years ( mean age , 28 . 8 years ) were examined for concentrations of IgA as functions of volume , total protein , and electrolyte conductivity ; some were also tested for IgG and IgM content .
 GENE: IgA; GENE: IgG; GENE: IgM
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
Answer:
 GENE: IgA; GENE: IgG; GENE: IgM