Interleukin 7 can enhance antigen-specific cytotoxic-T-lymphocyte and/or Th2-type immune responses in vivo.
Interleukin 7 (IL-7) protein has been reported to be important in the development of cytotoxic-T-lymphocyte (CTL) responses. However, other studies also support a partial Th2 phenotype for this cytokine. In an effort to clarify this unusual conflict, we compared IL-7 along with IL-12 (Th1 control) and IL-10 (Th2 control) for its ability to induce antigen (Ag)-specific CTL and Th1- versus Th2-type immune responses using a well established DNA vaccine model. In particular, IL-7 codelivery showed a significant increase in immunoglobulin G1 (IgG1) levels compared to IgG2a levels. IL-7 coinjection also decreased production of Th1-type cytokine IL-2, gamma interferon, and the chemokine RANTES but increased production of the Th2-type cytokine IL-10 and the similarly biased chemokine MCP-1. In herpes simplex virus (HSV) challenge studies, IL-7 coinjection decreased the survival rate after lethal HSV type 2 (HSV-2) challenge compared with gD plasmid vaccine alone in a manner similar to IL-10 coinjection, whereas IL-12 coinjection enhanced the protection, further supporting that IL-7 drives immune responses to the Th2 type, resulting in reduced protection against HSV-2 challenge. Moreover, coinjection with human immunodeficiency virus type 1 env and gag/pol genes plus IL-12 or IL-7 cDNA enhanced Ag-specific CTLs, while coinjection with IL-10 cDNA failed to influence CTL induction. Thus, IL-7 could drive Ag-specific Th2-type cellular responses and/or CTL responses. These results support that CTLs could be induced by IL-7 in a Th2-type cytokine and chemokine environment in vivo. This property of IL-7 allows for an alternative pathway for CTL development which has important implications for host-pathogen responses.
Sin
J I
JI
Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.
Kim
J
J
Pachuk
C
C
Weiner
D B
DB
Patchuk
C
C
D000818:Animals; D002455:Cell Division; D018932:Chemokine CCL2 / Q000378:metabolism; D018946:Chemokine CCL5 / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D005818:Genetic Engineering; D006558:Herpes Genitalis / Q000276:immunology / Q000517:prevention & control; D018258:Herpesvirus 2, Human / Q000276:immunology; D006801:Humans; D016753:Interleukin-10 / Q000235:genetics / Q000276:immunology; D018664:Interleukin-12 / Q000235:genetics / Q000276:immunology; D015851:Interleukin-7 / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010957:Plasmids; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D018417:Th1 Cells / Q000166:cytology / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology*; D014407:Tumor Cells, Cultured; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology
D018932:Chemokine CCL2; D018946:Chemokine CCL5; D016207:Cytokines; D015851:Interleukin-7; D014759:Viral Envelope Proteins; C040570:glycoprotein D-herpes simplex virus type 2; D016753:Interleukin-10; D018664:Interleukin-12