Selective expression of the HIV-1 Nef gene in these Tg mice is necessary and sufficient to induce an AIDS-like disease [79], characterized by failure to thrive, wasting, severe atrophy and fibrosis of lymphoid organs, a preferential depletion of CD4+ T-cells, with altered CD4+ T-cell proliferation in vitro, loss of CD4+ T-cell help, CD4+ T-cell and B-cell activation and impaired DC maturation and function [54,79,80,81,82,83]. Here, CD4 is linked to Failure to thrive.