FIGURE 3.

T-cell clone 42 recognizes both DBX and DBY antigens epitopes and DBX antigens endogenously processed and presented by mature dendritic cells (DCs). (A) Clone 42 was stimulated with autologous Epstein-Barr virus (EBV)-B cells pulsed with increasing concentrations of DBY 427–444 peptide and its DBX homologue DBX 429–446. IFN-γ secretion was measured in the culture supernatant after overnight incubation. Reactivity to a control peptide, DBX 201–218, is also shown. Disparate residues between DBX and DBY versions of the peptides are represented with underlined characters. (B) Patient’ (female) DCs (10⁴/well) were incubated for 24 hr with medium alone, poly-I/C, or lipopolysaccharide (LPS) to induce maturation. T-cell clone 42 (10⁴/well) was then added to the wells in the presence of IL-2 (50 U/mL). After 18 hr of incubation, secretion of IFN-γ was determined in cocultures by ELISA. Same assay was run simultaneously in the presence of anti-human leukocyte antigen (HLA)-DR mAb to block antigen presentation to the CD4 clone.