GPI⁻ EL4 cells were less efficient in proliferative activation of allogeneic CD4⁺ T cells than GPI⁺ EL4 cells.

Purified CD4⁺ T cells from a bm12 mouse were incubated with GPI⁻ (shaded) and GPI⁺ (black), I-A^b–expressing EL4 cells. Proliferation was assessed on day 4. Two similar experiments are shown; ▨ indicates GPI⁻; ▪, GPI⁺; and * indicates difference significant (P < .05).