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[Neutral alpha-mannosidase in human B- and T-lymphoid cells]
Insights
Neutral alpha-mannosidase activity was found in lymphoid cells, with higher levels in B-cell chronic lymphocytic leukemia (B-CLL) patients. Enzyme properties varied between B- and T-cells, offering potential diagnostic insights.
Area of Science:
- Biochemistry
- Cell Biology
- Immunology
Context:
- Neutral alpha-mannosidase activity is present in various lymphoid cells.
- Specific enzyme activity differs slightly in B-cells from B-cell chronic lymphocytic leukemia (B-CLL) patients.
Purpose:
- To investigate neutral alpha-mannosidase activity and properties in normal and pathological lymphoid cells.
- To compare neutral to acid alpha-mannosidase activity ratios in B- and T-cells.
Summary:
- Neutral alpha-mannosidase activity was detected in lymphoid cells, with a notable increase in B-CLL patients.
- Distinct neutral to acid alpha-mannosidase activity ratios were observed in B-cells versus T-cells.
- Partially purified neutral alpha-mannosidases from pathological B- and T-cells exhibited similar properties, including cytosolic localization, lability, and specific activation/inhibition profiles.
Impact:
- Characterization of neutral alpha-mannosidase provides insights into lymphoid cell function and pathology.
- Differential enzyme activity ratios may serve as biomarkers for distinguishing B- and T-cell populations.
- Understanding enzyme properties aids in developing targeted therapeutic strategies for hematological malignancies.
Abstract:
The presence of neutral alpha-mannosidase activity in normal and pathological lymphoid cells has been demonstrated. The specific activities of the enzyme in different cell types were similar with the exception of B-cells from B-CLL patients when it was a little higher. The activity of acid alpha-mannosidase was also determined in these lymphoid cells. The neutral to acid alpha-mannosidase activity ratio was different in B- and T-cells: in the former neutral alpha-mannosidase activity prevailed, whereas in the latter the predominance of acid alpha-mannosidase activity was apparent. Neutral alpha-mannosidases from pathological B- and T-cells were partially purified and their properties were investigated. In both cell types the enzyme was localized in the cytosol, was very labile and could be stabilized with Mn2+ and dithiothreitol. The enzyme was activated by Co2+ and inhibited by Zn2+ and EDTA. Swainsonine inhibited the B-cell neutral alpha-mannosidase somewhat more strongly in comparison with the T-cell enzyme.