Kinetics of the in vitro lymphocyte response to myelin basic protein in the the Lewis and Brown Norway strains of rat.

Several parameters of the in vitro lymphocyte proliferative response to myelin basic protein (BP) in Lewis (Le) and Brown Norway (BN) rats were examined. The results demonstrate that BN rats, a strain normally resistant to BP-induced experimental allergic encephalomyelitis, and Le rats, a strain readily susceptible to the disease, have similar patterns of the proliferative response to BP. An important difference, however, is that BN lymphocytes, although responding significantly to BP, are unable to proliferate to the same level as Le lymphocytes. In experiments measuring the lymphocyte response as a function of antigenic stimulus, days of culture, or type of adjuvant used, the BN rat peak response was in general 70% or less of the Le rat peak response. Furthermore, the BN lymphocyte response was reduced when B cells were removed whereas there was no effect in the Le rat. A negative feedback mechanism, possibly suppressor cells, has been suggested to explain these differences.