Figure 1. β-amyloid peptides do not stimulate divisions of healthy CD4⁺CD28⁺ lymphocytes and only weakly those of AD cells in vitro.

CD4⁺CD28⁺ lymphocyte proliferation was measured with DCT technique as described in Materials and Methods, after stimulation for 120 hours with Aβ 1–40 (A,B,G,H), Aβ 1–42(C,D,I,J) or Aβ 25–35 (E,F,K,L) at 0.2 or 0.5 µM as indicated. Proportion of dividing cells is given in each histogram as the net percent of total CD4⁺CD28⁺ population, obtained by subtracting the observed proportion of proliferating (CFSE-diluting) lymphocytes in untreated sample from the proportions observed for relevant samples treated with the Aβs. Results of an experiment involving paired material from a healthy, matched control (left panel, gray histograms A–F) and from an AD patient (right panel, black histograms G–L), representative of 5 experiments giving similar picture, are shown.