We examined the expression of IL-1 mRNA in vivo by in situ hybridization. RNA probes for murine IL-1α and IL-1β were used to detect IL-1 mRNA in frozen sections of spleen, lymph node, and thymus of mice injected with Salmonella typhi LPS or SRBC. No IL-1 was detected in lymphoid tissues from uninjected mice. This lack of expression correlated with the absence of IL-1 biologic activity. However, after LPS injection, IL-1α and β mRNA expression was found in macrophages of the red pulp and marginal zone of the spleen. The periarteriolar lymphoid sheath contained cells that only expressed IL-1β mRNA. These cells were not lymphocytes and did not stain with the macrophage marker F4/80. A similar cellular response was found after SRBC injection. Scattered macrophages in lymph nodes and thymus were positive, but only after LPS or SRBC injection. The spleens of mice injected with LPS had megakaryocytes containing IL-1 mRNA.
|Number of pages||7|
|Journal||Journal of Immunology|
|State||Published - Jan 1 1991|