Peptide-triggered IL-12 and IFN-γ mediated immune response in CD4⁺ T-cells against Leishmania donovani infection

Leishmania donovani are intracellular, human blood parasites that cause visceral leishmaniasis or kala-azar. Cell-penetrating peptides (CPPs) have been shown to modulate intracellular processes and cargo delivery, whereas host defense peptides (HDPs) promote proliferation of both naïve and antigen activated CD4⁺ T-cells. We report newly designed tripeptides that were able to trigger proinflammatory cytokine (IL-12 and IFN-γ) secretion by CD4⁺CD44⁺ T-cells in response to Leishmania donovani infection. These peptides can be used to induce antigen specific T_H¹ responses to combat obstacles of cytotoxicity and drug resistance associated with current anti-leishmanial drugs. Furthermore, these peptides can also be used as adjuvants to develop an effective immunoprophylactic approach for immunity restoration against visceral leishmaniasis.