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Production of a lymphocyte proliferation potentiating factor by purified polymorphonuclear leucocytes from mice and
Abstract:
Highly pure polymorphonuclear leucocytes (PMN) were prepared from peritoneal exudate cells which were induced by an i.p. injection of casein into C3H mice and rabbits. The PMN were tested for the production of a lymphocyte proliferation potentiating factor with various stimulations in vitro. In both animal species, the purified PMN from the inflammatory site 3 hr after injection (3-hr PMN) produced the factor upon stimulation with kaolin, while the purified PMN from the lesion 24 hr after injection (24-hr PMN) did not. The 3-hr PMN produced the potentiating factor during a relatively earlier period after in vitro stimulation with kaolin. Protein synthesis inhibitors did not inhibit the factor production, suggesting the release of a preformed factor from 3-hr PMN. The effect of kaolin did not appear to be simply due to its cytotoxicity, because the release was dependent on the metabolism of 3-hr PMN and not parallel with 51Cr-release from the PMN. The factor produced by mouse PMN had an MW of about 15,000-25,000; it consisted of two isoelectrophoretically distinct factors, i.e. pI 9.4 and 5.4. The rabbit PMN factor was slightly smaller (MW ranging between 10,000 and 20,000) than the mouse PMN factor and was composed of three pI species, i.e. 7.2, 5.4, and 4.5.
Insights
Polymorphonuclear leucocytes (PMN) isolated 3 hours post-injection produce a lymphocyte-potentiating factor when stimulated with kaolin. This pre-formed factor release is metabolism-dependent, unlike PMN isolated 24 hours post-injection.
Area of Science:
- Immunology
- Cell Biology
Background:
- Polymorphonuclear leucocytes (PMN) are key immune cells involved in inflammatory responses.
- Understanding the factors released by PMN during inflammation is crucial for elucidating immune mechanisms.
Purpose of the Study:
- To investigate the production of a lymphocyte proliferation potentiating factor by highly pure PMN from mice and rabbits.
- To characterize the conditions and nature of this factor's release.
Main Methods:
- Isolation of pure PMN from casein-induced peritoneal exudates in C3H mice and rabbits.
- In vitro stimulation of PMN with kaolin to assess factor production.
- Analysis of factor characteristics including molecular weight (MW) and isoelectric point (pI).
- Assessment of protein synthesis inhibitor effects and cytotoxicity of kaolin.
Main Results:
- PMN isolated 3 hours after casein injection (3-hr PMN) produced a lymphocyte proliferation potentiating factor upon kaolin stimulation, while 24-hr PMN did not.
- Factor production by 3-hr PMN occurred early after stimulation and was not inhibited by protein synthesis inhibitors, indicating a pre-formed factor.
- Kaolin's effect was metabolism-dependent and not solely cytotoxic.
- The mouse PMN-derived factor had an MW of 15,000-25,000 with pI 9.4 and 5.4.
- The rabbit PMN-derived factor had a slightly lower MW (10,000-20,000) and three pI species (7.2, 5.4, and 4.5).
Conclusions:
- Early-induced PMN release a pre-formed lymphocyte proliferation potentiating factor upon kaolin stimulation.
- This factor's release is an active, metabolism-dependent process.
- The factor exhibits species-specific biochemical properties.