Interleukin 10 (IL-10) and viral IL-10 strongly reduce antigen-speci[f_i]c human T cell proliferation by diminishing the antigen-presenting capacity of monocytes via downregulation of class II major histocompatibility complex expression - De Waal Malefyt, R; Haanen, J; Spits, H; Roncarolo, MG; te Velde, A; Figdor, C; Johnson, K; Kastelein, R; Yssel, H; de Vries, JE (J Exp Med, 1991)