ImmunoGrid: towards agent-based simulations of the human immune system at a natural scale. by Halling-Brown, M, Pappalardo, F, Rapin, N, Zhang, P, Alemani, D, Emerson, A, Castiglione, F, Duroux, P, Pennisi, M, Miotto, O, Churchill, D, Rossi, E, Moss, D, Sansom, C, Bernaschi, M, Lefranc, M, Brunak, S, Lund, O, Motta, S, Lollini, P, Murgo, A, Palladini, A, Basford, K, Brusic, V, Shepherd, A