The L.A.I. microtest: a rapid and sensitive precedure for the demonstration of cell-mediated immunity in vitro.

A new microtest for cell-mediated immunity is described, which is based on the elaboration of a diffusible factor from sensitized lymphocytes following contact with specific antigen. The factor inhibits the adherence of neighbouring leucocytes to plastic surfaces. Production of the factor is ablated by pretreatment of lymphocytes with Theta-antiserum. It is suggested that the factor may be a new lymphokine, leucocyte adherence inhibition factor (LAIF).