Quantitation of biologically active IL-1 by a sensitive assay based on immobilized human IL-1 receptor type II...

Area of Science:

• Immunology
• Biochemistry
• Cell Biology

Background:

• Interleukin-1 (IL-1) is a crucial cytokine involved in immune responses and inflammation.
• Accurate quantification of IL-1 isoforms is essential for understanding various physiological and pathological processes.
• Existing methods for IL-1 detection may lack sensitivity or specificity for biologically active forms.

Purpose of the Study:

• To develop a rapid and sensitive solid-phase radioassay for the quantitative detection of human interleukin-1 (IL-1).
• To enable the specific detection of biologically active IL-1.
• To allow for the precise determination of IL-1 isoform ratios in biological samples.

Main Methods:

• A solid-phase radioassay utilizing nitrocellulose-immobilized IL-1 receptors from human B cell lymphoma (Raji) was developed.
• The assay measures the binding of IL-1 to its solubilized receptor.
• A pretreatment procedure was devised to selectively remove IL-1 beta, facilitating isoform ratio determination.

Main Results:

• The assay demonstrated high sensitivity for human IL-1 beta (detecting levels as low as 1 x 10(-11) M).
• Lower sensitivity was observed for human IL-1 alpha and murine IL-1 beta.
• The assay specifically detects correctly folded, biologically active IL-1.
• The pretreatment method allowed for precise determination of IL-1 isoform ratios.

Conclusions:

• The developed radioassay provides a rapid, sensitive, and specific method for quantifying biologically active human IL-1.
• This assay is suitable for analyzing large numbers of biological samples, including plasma.
• The ability to determine IL-1 isoform ratios enhances its utility in research and diagnostics.