Feline one-way mixed leukocyte reaction

The feline one-way mixed leukocyte reaction (MLR) was accomplished by a microtechnique assay using gradient purified mononuclear leukocytes from the peripheral blood of specific-pathogen-free (SPF) cats. An eight day assay was required with an appropriate serum supplement of rabbit or cat serum and obtainable cell concentrations of 1×10⁵ mononuclear cells per well of each responder and stimulator population. This assay was devised as an $\text{in vitro}$ correlate of cell-mediated immunity and to demonstrate that feline histocompatibility differences can be detected in culture.