Adherent human blood monocytes were stimulated with heat-killed Staphylococcus albus in the presence of 35S-methionine and 3H-leucine. After 36 hours of incubation, the supernatant medium was purified over an anti-human endogenous pyrogen immunosorbent followed by gel-filtration, each fraction was assayed for lymphocyte activating factor (LAF) and active fractions were pooled for chromatofocusing. Chromatofocusing confirmed the three isoelectric points of IL-1. Each fraction was also precipitated with trichloroacetic acid and run on SDS-PAGE. Fluorography revealed that the intensity of the single radioactive polypeptide in each fraction correlated with LAF activity. Each band differed by about 2000 daltons. Pooled fractions were incubated with polymyxin B for 2 hours and then injected into rabbits. Only those fractions with LAF activity produced characteristic endogenous pyrogen fevers while fractions not containing LAF were non-pyrogenic. These studies suggest that the charge heterogeneity of IL-1 is associated with molecular weight differences and confirm previous studies that LAF and endogenous pyrogen appear to be identical molecules.
|Original language||English (US)|
|Number of pages||6|
|Journal||British Journal of Rheumatology|
|Issue number||SUPPL. 1|
|State||Published - 1985|
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