IL-15 is superior to IL-2 in the generation of long-lived antigen specific memory CD4 and CD8 T cells in rhesus macaques

Lack of IL-15 results in the suboptimal priming of CD4+T cell response against an intracellular parasite

“…Studies from our laboratory have shown that administration of exogenous IL-15 prolongs CD8 ϩ T cell response against T. gondii (9) and that blockade of this response inhibits the development of long-term CD8 ϩ T cell immunity against the parasite (18). Similarly, the role of IL-15 in the maintenance of memory CD8 ϩ T cell immunity against other infectious disease has been described (20,21,36). Because of its proinflammatory properties, the role of IL-15 in a number of autoimmune diseases has been demonstrated (37)(38)(39).…”

Interleukin-15 but Not Interleukin-7 Abrogates Vaccine-Induced Decrease in Virus Level in Simian Immunodeficiency Virusmac251-Infected Macaques

“…Prior studies on naive or SIV-infected macaques treated with rIL-7 protein have demonstrated that this cytokine alters T cell homeostasis (27,28,65) without altering SIV replication (66). The use of rIL-15 has been pioneered in naive macaques alone or together with Ags (26) and has been demonstrated to increase the frequency of long-lived CD4 ϩ and CD8 ϩ T cells. IL-15 treatment of a small number of SIV-infected macaques was reported not to affect viral replication (24,25).…”

“…In uninfected macaques immunized with tetanus toxoid or a live flu vaccine, rIL-15 increased long-term memory responses (26). In contrast, the administration of rIL-7 to healthy or SIV-infected macaques increased the proliferation of all T cell subsets and enhanced de novo thymic production (27)(28)(29).…”

“…Because murine studies indicate that IL-15 is important for both the initiation and maintenance of immune responses (18), this cytokine was administered at the time of immunization and maintained for three consecutive weeks. The dose of 10 g/kg was chosen because of the proven ability of the cytokine at this dose to increase specific responses to flu Ags in nonhuman primates (26).…”

IL-15 delays suppression and fails to promote immune reconstitution in virally suppressed chronically SIV-infected macaques

“…ART consisted of 20 mg/kg/d Tenofovir (PMPA, given subcutaneously; from Gilead Sciences), 40 mg/kg/d emtricitabine (FTC, given subcutaneously; from Gilead), and 100 mg/kg/BID raltegravir (Isentress, mixed with food; from Merck). Simian IL-15 was produced as described previously 21 and was given subcutaneously at 80 g/kg twice a week. ART was administered from day (d) 0 through d46.…”