Abstract: A method to characterize a T-cell response of a final population of T-lymphocytes resulting from the co-incubation of an initial population of T lymphocytes with a composition of antigen-presenting cells (APCs), said method comprising the steps of a) simultaneous measuring on a single cell basis at least two parameters: (i) proliferation of T lymphocytes and (ii) presence of a T cell antigen receptor on the surface of T lymphocytes and/or presence of at least one biological molecule produced by T lymphocytes, and the attribution of a positive or a negative value to each of these parameters, and b) classification of the final T-lymphocytes population into 2n different subsets of T lymphocytes, n being the number of parameters, each subset being characterized by a positive or a negative value respectively to each parameter and the determination of the proportion of T lymphocytes present in each subset with respect to the number of T lymphocytes in the final population, with said proportion being characteristic