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Ontogeny of cells involved in the suppressor circuit of the immune response
Abstract:
Some macrophage (M phi) cell surface structures which bind T cell-derived factors remain intact after the M phi are killed by heating at 56 degrees C (but not 72 degrees C) for 45 min. As a result, appropriately killed M phi (HK M phi) can act as competitive antagonists for those M phi functions which are involved in binding and active presentation of T cell-derived regulatory signals. By blocking the transmission of these signals with HK M phi, we have found that the spleens of newborn mice contain considerable numbers of "latent" helper cells whose activity is not ordinarily seen because it is overridden by suppressor mechanisms. Similarities between these neonatal helper cells and a subset of adult T helper "inducer" cells (cell surface phenotype Ly-1+; Ly-2-, 3-; IJ+; Qa 1+), whose activity appears in significant numbers only after immunization, are described.
Insights
Heat-killed macrophages (HK M phi) can block T cell signals, revealing "latent" helper cells in newborn mice. These cells resemble adult T helper inducer cells, suggesting a conserved immune regulatory mechanism.
Area of Science:
- Immunology
- Cell Biology
Background:
- Macrophage (M phi) surface structures bind T cell factors.
- These structures remain intact after M phi are killed by heating at 56°C.
Purpose of the Study:
- To investigate the role of heat-killed macrophages (HK M phi) as antagonists.
- To identify and characterize "latent" helper cells in newborn mice.
Main Methods:
- Utilized heat-killed macrophages (HK M phi) to block T cell signal transmission.
- Analyzed spleen cells from newborn mice.
Main Results:
- HK M phi competitively antagonize M phi functions in binding and presenting T cell signals.
- Newborn mouse spleens contain "latent" helper cells, normally suppressed.
- Neonatal helper cells share similarities with adult T helper inducer cells (Ly-1+, Ly-2-, 3-, IJ+, Qa 1+).
Conclusions:
- HK M phi can be used to uncover suppressed immune cell activities.
- A population of latent helper cells exists in neonatal mice, regulated by suppressor mechanisms.
- These findings suggest a conserved pathway for T cell regulation involving helper inducer-like cells.