Kinetics of the effect of a single dose of cyclosporin-A on antibody and cell mediated immune responses in the guinea pig.

The effect of 100 mg/kg cyclosporin-A (CS-A), given as a single dose either before or after immunization, on antibody levels and skin test reactivity was investigated. CS-A was found to suppress both primary and secondary anti-hapten and anti-carrier IgG1 and IgG2 antibodies. However, CS-A was also capable of inducing enhanced anti-hapten antibodies. CS-A showed a similar effect on contact sensitivity reactions to 2,4-dinitrofluorobenzene (DNFB) as has been shown for cyclophosphamide (CY) in that, given before sensitization, skin reactions were enhanced, whereas given after sensitization they were suppressed. However, the effect of CS-A on the T-cell proliferation in the lymph node, draining the site of sensitization to DNFB, differed from that of CY. Although CS-A induced a depression of T-cell proliferation, this suppression was more prolonged than that found in CY treated animals. Also, these draining lymph nodes never showed increased T-cell proliferation as did those in animals treated with CY before sensitization. This work demonstrates that a single dose of CS-A can both suppress or enhance antibody production and delayed hypersensitivity. The timing of the dose of CS-A in relation to the time of primary immunization is important. However, both IgG1 and IgG2 primary and secondary antibody responses can be altered. Comparison with the effect of CY on antibody levels and contact sensitivity would indicate that in some ways CS-A reacts similarly to antimitotic agents and in other ways is different.