The detection by immunofluorescence of distinct cell populations producing interleukin-1 alpha and interleukin-1 beta in activated human peripheral blood.

An immunofluorescent staining method using specific monoclonal antibodies was used to detect IL-1 alpha and IL-1 beta in individual cells in stimulated human peripheral blood. No staining was seen in unstimulated cells but intense, maximal staining of approximately 5% of the cells was seen 20-24 h after activation with PHA/PMA. The large irregularly shaped stained cells were surrounded by smaller unstained cells with lymphocyte-like morphology. By 44 h post activation a few cells only showed weak staining. The staining pattern was different for the two molecules studied, with a granular pattern for IL-1 alpha staining and diffuse cytoplasmic staining for IL-1 beta. Staining post-activation could be abolished by preincubation of the monoclonal antibody with the appropriate recombinant IL-1, but not by pre-incubation with the other IL-1 type. When both anti-IL-1 alpha and anti-IL-1 beta were used together two populations of cells were identified; one had the granular staining as seen with anti-IL-1 alpha alone and the other had the diffuse staining pattern as seen with anti-IL-1 beta. The percentage of cells showing bright staining with anti-IL-1 alpha and anti-IL-1 beta together was approximately equal to the sum of the percentage of cells staining for IL-1 alpha or IL-1 beta alone. This study demonstrates a method for the detection of individual IL-1 alpha- and IL-1 beta- producing cells and suggests that in activated human peripheral blood IL-1 alpha and IL-1 beta are produced by separate populations of cells.