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Human lymphocytes lack substance P receptors
A I Roberts1, J Taunk, E C Ebert
1Department of Medicine, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Brunswick 08903.
Cellular Immunology
|May 1, 1992
Summary
Substance P (SP) does not significantly impact human lymphocyte proliferation or cytotoxicity. Researchers found no SP receptors on lymphocytes from blood, spleen, or gut, challenging previous findings on SP's immunomodulatory effects.
Area of Science:
- Immunology
- Neuroscience
- Gastroenterology
Background:
- Substance P (SP) is a neuropeptide abundant in the gut with known immunomodulatory actions.
- Previous studies suggested SP influences immune cell function, but its specific effects on lymphocytes and receptor presence were unclear.
Purpose of the Study:
- To investigate the effects of Substance P on human peripheral blood lymphocytes (PBL) and jejunal intraepithelial lymphocytes (IEL).
- To determine the expression of SP receptors on various human lymphocyte types.
Main Methods:
- Lymphocyte proliferation and cytotoxicity assays were performed with and without SP treatment.
- Radioligand binding studies using Scatchard analysis were employed to quantify SP receptors on different lymphocyte populations.
- IM-9 B lymphoblastoid cells served as a positive control for SP receptor detection.
Main Results:
- SP (10^-8 or 10^-12 M) did not alter spontaneous or mitogen-induced proliferation of PBL or IEL.
- SP did not affect spontaneous cytotoxicity of PBL or IEL.
- No significant SP receptors were detected on PBL, polymorphonuclear leukocytes, splenocytes, IEL, or jejunal lamina propria lymphocytes.
Conclusions:
- The findings dispute the presence of substantial SP receptors on lymphocytes in peripheral blood, spleen, and intestinal mucosa.
- These results suggest that SP may not have a major direct effect on T cell proliferation or spontaneous cytotoxicity in these cell types.