Interleukin production by neonatal spleen cells during and as a result of antigen presentation: the effect of ultraviolet light.

Antigen presentation by neonatal murine spleen cells and the production of lymphokines and interleukins involved in the stimulation of a T-helper-2 (TH2) cell line (D10-G4.1) were studied as were the effects of ultra violet (UV)-irradiation on this system. Neonatal spleen cells are less capable than adult cells of performing the initial steps of the immune response required for antigen dependent activation of TH2 cells. These steps include soluble antigen processing and presentation and as a result reduced production of IL-4 and IL-1-Inducer Factor ("IL-1-IF") by the T-helper cells and reduced production of IL-1 and IL-2 by the antigen presenting cell population. Spontaneous membrane IL-1 activity is low in the neonate, however, when exposed to "IL-1-IF" they can express adult levels. Ultra-violet (UV) irradiation of the antigen presenting population has a damaging effect on all the above mentioned processes. Antigen processing and presentation, induction of D10 IL-4 production and proliferation, and IL-2 production demonstrate two different age related patterns of UV-irradiation induced damage: a dose dependent inhibition when adult cells are irradiated and an inverse effect in which low doses of irradiation were more inhibitory than higher doses when neonatal cells are irradiated. However, the secretion and membrane expression of IL-1 by both age groups are directly and totally inhibited by the range of UV-irradiation doses used and cannot be reinduced with a supplement of a crude "IL-1-IF". While the capacity to produced IL-1 is totally destroyed by UV-irradiation, the ability to produce IL-2 remains intact and remains responsive to an "IL-2-Inducer" activity during proper antigen presentation. The low responses of neonatal antigen presenting spleen cell populations and the damaging effect of UV on both neonatal and adult responses are not due to the induction of suppressor factors.