REDUCED IMMUNE-RESPONSES IN RHESUS-MONKEYS SUBJECTED TO DIETARY RESTRICTION

Dietary restriction (DR) has emerged as a major paradigm in experiment al gerontology. The effects of DR on rodents are numerous and include reduced rates of immunologic aging, delayed morbidity, and increases i n longevity. The effects of DR on primate species remain largely unkno wn. We began a randomized trial of long-term, adult-onset DR in rhesus monkeys (Macaca mulatta) in 1989. This report describes some early di fferences in immunologic function after two to four years of DR. Perip heral blood mononuclear cells were studied for mitogen-induced prolife ration, natural killer (NK) cell lysis, and expression of cell surface antigens. Antibody response to influenza vaccine and the number of pe ripheral blood lymphoctyes were also measured. Unexpectedly, concanava lin A and pokeweed mitogen response measures were reduced in restricte d monkeys compared to controls (p less than or equal to .01). NK activ ity and antibody responses were also reduced (p < .05). Neither cell s urface antigens nor peripheral blood lymphocyte counts appear affected by DR thus far.