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OKT3-associated adverse reactions: mechanistic basis and therapeutic options
M Suthanthiran1, M Fotino, R R Riggio
1Department of Medicine, Cornell University Medical College, New York, NY.
Abstract:
OKT3, a prototypic monoclonal antibody directed at the lineage-specific CD3 antigen expressed on mature T cells, is an effective immunosuppressant in organ graft recipients. Unfortunately, a variety of adverse reactions are observed following the first and second doses of OKT3. In a series of experiments designed to examine the signaling repertoire of OKT3, it was found that (1) OKT3 is an effective substitute for the alloantigen stimulus in the activation of antigen-specific memory T cells; (2) OKT3 is a potent inducer of cytolytic activity (secondary cytotoxic T-cell activity as well as natural killer-cell activity); (3) OKT3 is also an inducer of interleukin-2 and interferon gamma production; and (4) of the immunosuppressants currently in clinical use, cyclosporine greater than methylprednisolone greater than 6-mercaptopurine (an in vivo cleavage product of azathioprine) in curtailing T-cell activation with OKT3. Collectively, these observations suggest a potential mechanistic basis for the adverse reactions associated with OKT3 and provide experimental support for therapeutic strategies that include the use of cyclosporine and/or methylprednisolone before OKT3 administration.
Insights
OKT3 monoclonal antibody activates T cells, inducing adverse reactions. Cyclosporine and methylprednisolone may mitigate these effects by inhibiting T-cell activation, suggesting pre-administration strategies.
Area of Science:
- Immunology
- Transplantation Medicine
- Pharmacology
Background:
- OKT3 is a monoclonal antibody targeting the CD3 antigen on T cells, used for immunosuppression in organ transplantation.
- Adverse reactions frequently occur after initial OKT3 administration.
Purpose of the Study:
- To investigate the signaling pathways and cellular effects of OKT3.
- To identify potential strategies for mitigating OKT3-induced adverse reactions.
Main Methods:
- Experiments examining the T-cell activation and cytokine production induced by OKT3.
- Comparative analysis of immunosuppressants (cyclosporine, methylprednisolone, 6-mercaptopurine) in curtailing OKT3-mediated T-cell activation.
Main Results:
- OKT3 activates antigen-specific memory T cells and induces cytolytic activity (CTL and NK cells).
- OKT3 stimulates the production of interleukin-2 and interferon-gamma.
- The efficacy of immunosuppressants in reducing OKT3-induced T-cell activation followed the order: cyclosporine > methylprednisolone > 6-mercaptopurine.
Conclusions:
- OKT3's signaling properties provide a mechanistic basis for observed adverse reactions.
- Pre-treatment with cyclosporine and/or methylprednisolone may be a viable strategy to manage OKT3-related adverse events.