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Rosette-increasing factor (RIF) generated in vivo following PHA skin test
Clinical and Experimental Immunology
|May 1, 1981
Summary
A novel factor, rosette-increasing factor (RIF), appears in the blood after a phytohaemagglutinin (PHA) skin test. This RIF, produced by T lymphocytes, indicates cellular immune competence.
Area of Science:
- Immunology
- Cellular Immunology
Background:
- Phytohaemagglutinin (PHA) skin testing is used to assess delayed cutaneous hypersensitivity.
- The immune response involves complex interactions and signaling molecules.
Purpose of the Study:
- To identify and characterize a factor appearing after PHA skin testing.
- To investigate the cellular origin and regulation of this factor.
- To explore its potential as a marker for cellular immune competence.
Main Methods:
- PHA skin testing in individuals.
- Serum and mononuclear cell culture supernatant analysis.
- Cell fractionation using E rosetting and nylon-wool columns.
- Inhibition studies using cytochalasin B, colchicine, and cycloheximide.
Main Results:
- A rosette-increasing factor (RIF) was detected in serum 6-14 hours after PHA skin testing.
- RIF production was linked to delayed cutaneous hypersensitivity.
- RIF was identified as a product of T lymphocytes.
- RIF production requires new protein synthesis for early activation steps and is inhibited by cytochalasin B but not colchicine.
Conclusions:
- RIF is a lymphokine synthesized during active immune responses in vivo.
- Assaying RIF in vivo may offer a new method for evaluating cellular immune competence.