[Experimental hypersensitivity pneumonitis and enhancement of granuloma formation by low dose irradiation with increased interleukin-1 activity of granuloma in genetically low responder mouse (C3H)].

Possible enhancing effects by low dose total body irradiation on pulmonary granuloma formation induced by intratracheal injection of ovalbumin-coupled beads in low responder C3H mouse were studied. The low dose (3.5 Gy) irradiation increased the size of granuloma in low responder C3H mouse as large as the granuloma formed in high responder C57BL/10 mouse. The resolution of granuloma which usually disappeared within 9 days was also prolonged by the irradiation. Increase in IL-1 activity of lung extracts but not IL-2 activity was parallel to the enhancement of granuloma formation and/or the delayed resolution of granuloma. These results indicated that the radiation-sensitive cells might regulate IL-1 producing cell, possibly macrophages which made pulmonary granuloma.