Key Event Title
|Level of Biological Organization|
Key Event Components
Key Event Overview
AOPs Including This Key Event
|AOP Name||Role of event in AOP|
|Homo sapiens||Homo sapiens||High||NCBI|
|Mus musculus||Mus musculus||High||NCBI|
|Rattus norvegicus||Rattus norvegicus||High||NCBI|
|All life stages||High|
Key Event Description
Antibody production to T cell -dependent antigens is established through the coordination of B cells, antigen-presenting cells as well as T cell -derived cytokines which stimulates B cells to proliferate and differentiate. T cell -dependent antibody response (TDAR) might be altered if at least one of these cell populations is affected. Calcineurin inhibitors (CNIs) are known to impair T-cell dependent antibody response, but have not been shown to directly affect B cells to reduce antibody production.
FK506 and cyclosporine A (CsA) suppresses the production of IL-2, IL-4 and other classes of cytokines in T cells. IL-2 stimulates B cells to proliferate through surface IL-2 receptors. IL-4 stimulates B-cells to proliferate, to switch immunoglobulin classes, and to differentiate into plasma and memory cells. Suppressing the production of these B-cell -related cytokines appears to be the main factor in impairment of TDAR by FK506 (Heidt et al, 2009).
How It Is Measured or Detected
TDAR could be examined in vivo and in vitro.
In usual in vivo studies, antigen-specific antibodies are evaluated with measuring of serum antibody levels by ELISA or with plaque-forming cell (PFC) assay.
- Rats were repeatedly administered FK506 orally for 4 weeks and immunized with KLH, after which the serum was examined for T cell dependent, antigen-specific IgM and IgG levels using a Sandwich ELISA kit (Ulrich et al. 2004).
- Mice were repeatedly administered CNI including FK506 and CsA orally for 4 days and immunized with SRBC, after which spleen cells were examined using a PFC assay (Kino et al. 1987).
In vitro studies, total IgM and IgG levels in culture supernatant are often measured after polyclonal T-cell activation instead of antigen stimulation in immune cell cultures.
- T cells and B cells isolated from human PBMC were co-cultured with a CNI for nine days in the presence of polyclonal T cell stimulation, after which supernatants were tested for immunoglobulin IgM and IgG levels using a Sandwich ELISA kit. FK506 or CsA reduced the levels of IgM and IgG at the concentrations of 0.3 and 1.0 ng/mL or 50 and 100 ng/mL (Heidt et al, 2009).
- SKW6.4 cells (IL-6-dependent IgM-secreting human B-cell line) were cultured with anti-CD3/CD28 antibody-stimulated PBMC culture supernatant. After culturing for four days, IgM produced in the culture supernatants was measured using an ELISA kit. FK506 or CsA reduced the levels of IgM at the concentrations of 0.01 to 100 ng/mL or 0.1 to 1000 ng/mL (Sakuma et al. 2001b).
- In order to examine class switching, T cells derived from human PBMCs were cultured with CNI, and cytokine mRNA levels of IFN-gamma, IL-2, IL-4, IL-5, IL-10, IL-13 and other B cell stimulatory cytokines produced in T cells were measured by quantitative PCR (Dumont et al. 1998).
Domain of Applicability
CNI induced impairment of TDAR is demonstrated with rodent studies. That is, oral administration of FK506 or CsA to mice for 4 days impaired the response of PFC in splenocytes after intravenous immunization with sheep erythrocytes (Kino et al. 1987). Likewise, oral administration of FK506 to rats over a four-week period reduced production of both anti-KLH-IgG and IgM antibodies after subcutaneous immunization with KLH (Ulrich et al. 2004). As for humans, in vitro experiments showed that treatment with FK506 or CsA of peripheral blood mononuclear cells from blood-bank donors suppressed the production of IgM and IgG antibodies specific to T-cell dependent antigens. (Heidt et al, 2009) Also, in SKW6.4 cells (IL-6-dependent IgM-secreting human B- cell line) cultures, FK506 or cyclosporin suppressed the production of IgM antibodies in the presence of T-cell activation. (Sakuma et al. 2001b) These findings strongly suggest that CNI -induced impairment of TDAR occurs at least in common among humans and rodents.
Evidence for Perturbation by Stressor
Regulatory Significance of the Adverse Outcome
ICH Harmonised tripartite guideline Immunotoxicity studies for human pharmaceuticals S8
- Heidt, S., Roelen, D. L., Eijsink, C., Eikmans, M., van Kooten, C., Claas, F. H. and Mulder, A. (2010). Calcineurin inhibitors affect B cell antibody responses indirectly by interfering with T cell help. Clinical and experimental immunology. 159(2): 199-207.
- Sakuma, S., Kato, Y., Nishigaki, F., Magari, K., Miyata, S., Ohkubo, Y., and Goto, T. (2001b). Effects of FK506 and other immunosuppressive anti-rheumatic agents on T cell activation mediated IL-6 and IgM production in vitro. International Immunopharmacology 1(4): 749-57.
- Kino, T., Hatanaka, H., Hashimoto, M., Nishiyama, M., Goto, T., Okuhara, M., Kohsaka, M., Aoki, H. and Imanaka, H. (1987). FK-506, a novel immunosuppressant isolated from a Streptomyces. I. Fermentation, isolation, and physico-chemical and biological characteristics. Journal of antibiotics. 40(9): 1249-1255.
- Ulrich, P., Paul, G., Perentes, E., Mahl, A., and Roman D. (2004). Validation of immune function testing during a 4-week oral toxicity study with FK506. Toxicology Letters 149(1-3): 123-31.
- Dumont, F.J., Staruch, M.J., Fischer, P., DaSilva, C. and Camacho, R. (1998). Inhibition of T cell activation by pharmacologic disruption of the MEK1/ERK MAP kinase or calcineurin signaling pathways results in differential modulation of cytokine production. Journal of immunology 160 (6): 2579-89.