Interestingly, naive CD4+ T cells exposed to phenylalanine or isoleucine acquire an activated Th1 phenotype, and the oral treatment of mouse models of AD with the prebiotic oligosaccharide GV-971 (which suppresses gut dysbiosis) reduced the concentration of phenylalanine and isoleucine, resulting in the amelioration of neuroinflammation and cognitive impairment (114). The gene discussed is CD4; the disease is Alzheimer disease.