Figure 1.

Potential immunotherapy targets to manipulate CD4⁺ T cell-dendritic cell (DC) and CD4⁺ T cell-infected macrophage (MΦ) interactions during leishmaniasis include both cognate and soluble cytokine signals. Primary signals between CD4⁺ T cells and macrophages or DCs through major histocompatibility complex class II antigen presentation of parasite peptide to the T cell receptor are indicated (red), as are both positive (green), and negative (orange) costimulatory signals. Positive (blue) and negative (purple) soluble cytokine signals are also show. Note that many of these signals are bidirectional, as indicated by the double-ended arrows. In addition, molecules highlighted by an asterisk have been reported to have the opposite effects in different type of Leishmania species infections. Amastigotes residing in macrophages are shown in black.