Suppression of Interleukin-2 Production and Activity by Factor(s) Released by Peripheral Blood Mononuclear Cells during Papillomavirus Infections

Supernatant fluids from cultured peripheral blood mononuclear cells (PBMC) obtained from patients with extensive papillomavirus infections such as condyloma acuminatum (CA) and epidermodysplasia verruciformis (EV) depressed the proliferative responses of T cells to phytohemagglutinin-P (PHA-P) and the production of interleukin-2 (IL-2) from those preparations. Fluids from the same cultures also inhibited the mitogenic activity of IL-2 on CTLL-2 cells as IL-2–dependent target cells. These soluble suppressor factors (SSF) from PBMC were present in significantly higher concentrations in fluids from cultured PBMC from patients in comparison to healthy controls. A soluble suppressor factor was characterized also from cultured rabbit PBMC after the rabbits had been infected with Shope papillomaviruses. This suppressor factor likewise inhibited IL-2 production and IL-2 activity.