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Transfer factor--a lymphocyte cell surface component.
Allergologia Et Immunopathologia
|January 1, 1984
Summary
The biologically active component of lymphocyte-derived extracts (DLE) is primarily a peptide fraction detached from the cell surface by trypsin. This surface peptide fraction exhibits significant T-cell factor (TF) activity, crucial for biological function.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Lymphocytes play a critical role in immune responses.
- Identifying biologically active components within lymphocytes is essential for understanding cellular function.
- Previous studies suggested the presence of T-cell factors (TF) in lymphocyte extracts.
Purpose of the Study:
- To isolate and characterize the biologically active component responsible for T-cell factor (TF) activity in lymphocyte-derived extracts (DLE).
- To determine the cellular origin (cell surface vs. cell interior) of the TF activity.
- To assess the biological activity and potential for separation of the identified active fraction.
Main Methods:
- A recovery assay was employed using trypsinized human lymphocytes to assess sheep cell-rosetting capacity.
- Lymphocyte extracts were fractionated after trypsination.
- Comparisons were made between extracts from trypsinized leukocytes and the leukocyte supernatant.
- Fractionation involved separating peptide components based on their release by trypsin treatment.
Main Results:
- The majority of TF activity in whole lymphocytes was attributed to a peptide fraction released from the cell surface by trypsin treatment.
- A distinct fraction (Fraction III) originating from the cell interior, characterized by high UV absorption (A 260/280) likely due to nucleotide content, showed no TF activity after trypsination.
- The biologically active TF fraction (Fraction II) was successfully released into the supernatant upon trypsination and consists of cell surface peptides.
- Fraction II demonstrated high biological activity, detectable at concentrations as low as 1 microgram/ml.
Conclusions:
- The primary biologically active component of DLE with TF activity resides in a cell surface peptide fraction.
- This surface peptide fraction can be effectively released and separated using trypsin treatment.
- The findings highlight the importance of cell surface components in lymphocyte-mediated biological activities.