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A subset of human rosetted lymphocytes contains previously unidentified histamine
M M Khan1, D M Fishwild, K L Melmon
1Department of Medicine, Stanford University School of Medicine, California 94305.
Insights
Researchers isolated a lymphocyte subset rich in histamine using sequential immunoadsorption. This subset, identified as Leu-5+ (OKT-11) and Leu-15+, contains significant histamine levels and lacks other T-cell markers.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Histamine is a key mediator in immune responses.
- Specific lymphocyte subsets play crucial roles in immune regulation.
- Identifying novel cell populations with unique functions is essential for understanding immunity.
Purpose of the Study:
- To isolate and characterize a lymphocyte subset with high histamine concentration.
- To determine the immunological markers of this histamine-rich cell population.
- To investigate the potential role of this subset in immune function.
Main Methods:
- Sequential solid-phase immunoadsorption (panning) was employed for cell isolation.
- A radioenzymatic assay was utilized for precise histamine quantification.
- Immunophenotyping was performed using a panel of monoclonal antibodies (Leu-4, Leu-3, Leu-2, Leu-5, Leu-15, 9.3).
Main Results:
- A distinct lymphocyte subset, comprising 3-7% of rosetted cells, was successfully isolated.
- This subset demonstrated high histamine concentrations, measuring 117 ng/1 x 10(6) cells.
- The isolated cells were identified as Leu-5+ (OKT-11) and Leu-15+, while being negative for Leu-4, Leu-3, Leu-2, and 9.3 antigens.
- The absence of basophils in this subset was confirmed.
Conclusions:
- A novel Leu-5+, Leu-15+ lymphocyte subset with significant histamine content has been identified.
- This subset represents a distinct cell population separate from basophils and other characterized T-cell subsets.
- The precise immunological function of this histamine-rich lymphocyte subset remains to be elucidated.
Abstract:
By sequential solid-phase immunoadsorption (panning) steps, we have isolated a subset of lymphocytes (comprising 3-7% of rosetted cells) that contains high concentrations of histamine. We have used a radioenzymatic assay for the determination of histamine and have located 117 ng of histamine/1 x 10(6) cells in Leu-5+ (OKT-11), Leu-15+ cells. This subset did not contain basophils and was negative for Leu-4 (OKT-3), Leu-3 (OKT-4), Leu-2 (OKT-8), and 9.3 antigens. The function of this subset of rosetted cells has not been determined.