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Functional domains of the CD11a adhesion molecule in lymphokine activated killer (LAK)-mediated cytolysis
S J Mentzer1, M A Crimmins, S H Herrmann
1Division of Pediatric Oncology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115.
To study the functional role of the CD11a cell surface molecule in antigen nonspecific cytolysis, a homogenous population of human lymphokine activated killer (LAK) cells were obtained after more than two months of culture in recombinant interleukin-2 (IL-2). Dual parameter immunofluorescence analysis demonstrated that LAK cells from long-term cultures were predominantly CD3+ and CD8+ cells. Monoclonal antibodies (MAb) to six function-associated cell surface molecules were used to inhibit the LAK-target cell interaction. MAb inhibition indicated that the CD11a was involved in the LAK-target cell interaction. None of the other function-associated MAb inhibited killing. A panel of MAb to both the alpha and beta subunits of the CD11a molecule confirmed the anti-CD11a inhibition and demonstrated a hierarchy of functional epitopes. The dominant utilization of CD11a did not appear to depend on IL-2 induction of CD11a surface expression. CD11a surface expression on CD3+ cells did not increase after incubation with IL-2 or other mediators. These findings indicate that CD11a is an important regulatory molecule in LAK-target cell interactions and may play a role in the ability of LAK cells to effectively interact with potential target cells.
To study the functional role of the CD11a cell surface molecule in antigen nonspecific cytolysis, a homogenous population of human lymphokine activated killer (LAK) cells were obtained after more than two months of culture in recombinant interleukin-2 (IL-2). Dual parameter immunofluorescence analysis demonstrated that LAK cells from long-term cultures were predominantly CD3+ and CD8+ cells. Monoclonal antibodies (MAb) to six function-associated cell surface molecules were used to inhibit the LAK-target cell interaction. MAb inhibition indicated that the CD11a was involved in the LAK-target cell interaction. None of the other function-associated MAb inhibited killing. A panel of MAb to both the alpha and beta subunits of the CD11a molecule confirmed the anti-CD11a inhibition and demonstrated a hierarchy of functional epitopes. The dominant utilization of CD11a did not appear to depend on IL-2 induction of CD11a surface expression. CD11a surface expression on CD3+ cells did not increase after incubation with IL-2 or other mediators. These findings indicate that CD11a is an important regulatory molecule in LAK-target cell interactions and may play a role in the ability of LAK cells to effectively interact with potential target cells.