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Expression of ICAM-1 (CD54) on normal and leukaemic B cells: implication for the mixed lymphocyte reaction
M R Padros1, M I Noli, L Fainboim
1Laboratorio de Immunogenética, Hospital de Clinicas José de San Martin, Facultad de Medicina, Buenos Aires, Argentina.
Insights
Normal B cells are poor stimulators in mixed lymphocyte reactions (MLR). Activation increases their stimulatory capacity, linked to ICAM-1 (CD54) expression. This molecule is crucial for B cell allogeneic stimulation in MLR.
Area of Science:
- Immunology
- Cell Biology
Background:
- B lymphocytes play a role in immune responses.
- The mixed lymphocyte reaction (MLR) is a key model for studying T cell activation and allogeneic responses.
- Intercellular Adhesion Molecule-1 (ICAM-1), also known as CD54, is involved in cell-cell interactions.
Purpose of the Study:
- To investigate the role of B lymphocytes in the mixed lymphocyte reaction (MLR).
- To determine the correlation between ICAM-1 (CD54) expression and the stimulatory capacity of B cells in MLR.
- To explore the potential of ICAM-1 as a target for modulating B cell-mediated allogeneic stimulation.
Main Methods:
- Mixed lymphocyte reaction (MLR) assays using peripheral blood normal B lymphocytes and activated B cells.
- Flow cytometry to assess the expression of ICAM-1 (CD54) on B cells.
- Inhibition studies using antibodies against ICAM-1.
Main Results:
- Normal peripheral blood B lymphocytes exhibited poor stimulatory capacity in MLR.
- Activated B cells demonstrated significantly enhanced stimulatory capacity in MLR.
- Increased expression of ICAM-1 (CD54) on the surface of activated B cells correlated with their heightened stimulatory potential.
- Leukaemic B cells also showed MLR stimulatory capacity that was restricted to ICAM-1 (CD54) positive cells.
- Antibodies targeting ICAM-1 effectively blocked the allogeneic stimulation induced by both normal activated and leukaemic B cells in MLR.
Conclusions:
- ICAM-1 (CD54) expression is a critical factor determining the allostimulatory capacity of B cells in the mixed lymphocyte reaction.
- Activated and leukaemic B cells with higher ICAM-1 expression are potent stimulators in MLR.
- Targeting ICAM-1 offers a potential strategy to inhibit B cell-mediated allogeneic responses.
Abstract:
Peripheral blood normal B lymphocytes were found to be poor stimulators in the mixed lymphocyte reaction (MLR), in contrast to normal activated B cells which were strong stimulators. This increased capacity to stimulate a strong MLR correlated with an increased expression of the ICAM-1 (CD54) molecule on the surface of these cells. Similarly, the capacity of leukaemic B cells to induce an allogenic stimulation in the MLR was limited to the ICAM-1 (CD54) positive leukaemic cells. The ability of normal activated or leukaemic B cells to induce an MLR was blocked by antibodies directed against ICAM-1.