Intranasal Immunization with RecombinantLactococcus lactisSecreting Murine Interleukin-12 Enhances Antigen-Specific Th1 Cytokine Production

Abstract

Interleukin-12 (IL-12), a heterodimeric cytokine, plays an important role in cellular immunity to several bacterial, viral, and parasitic infections and has adjuvant activity when it is codelivered with DNA vaccines. IL-12 has also been used with success in cancer immunotherapy treatments. However, systemic IL-12 therapy has been limited by high levels of toxicity. We describe here inducible expression and secretion of IL-12 in the food-grade lactic acid bacterium Lactococcus lactis. IL-12 was expressed as two separate polypeptides (p35-p40) or as a single recombinant polypeptide (scIL-12). The biological activity of IL-12 produced by the recombinant L. lactis strain was confirmed in vitro by its ability to induce gamma interferon (IFN-␥) production by mouse splenocytes. Local administration of IL-12-producing strains at the intranasal mucosal surface resulted in IFN-␥ production in mice. The activity was greater with the single polypeptide scIL-12. An antigen-specific cellular response (i.e., secretion of Th1 cytokines, IL-2, and IFN-␥) elicited by a recombinant L. lactis strain displaying a cell wall-anchored human papillomavirus type 16 E7 antigen was dramatically increased by coadministration with an L. lactis strain secreting IL-12 protein. Our data show that IL-12 is produced and secreted in an active form by L. lactis and that the strategy which we describe can be used to enhance an antigen-specific immune response and to stimulate local mucosal immunity.

A Novel Mucosal Vaccine Based on Live Lactococci Expressing E7 Antigen and IL-12 Induces Systemic and Mucosal Immune Responses and Protects Mice against Human Papillomavirus Type 16-Induced Tumors

“…Moreover, IL-12 possesses adjuvant properties when codelivered with Ags and has been successfully used in cancer immunotherapy. Intranasal administration with these recombinant L. lactis strains induces an E7-specific immune response in mice (9,10,13). These encouraging results prompted us to explore whether coadministration of LL-E7 and LL-IL-12 could be used for immunization and immunotherapy of HPV-related CxCa.…”

“…The construction of recombinant L. lactis strains anchoring HPV-16 E7 Ag (LL-E7) and secreting biologically active murine IL-12 (LL-IL-12) has been previously described (9,10,13).…”

Des bactéries pour prévenir et traiter le cancer du col de l’utérus induit par le papillomavirus humain de type 16

“…Nous avons pu mettre en évidence une réponse immune spécifique d'E7 chez des souris à la suite de l'administration de LL-E7 [5,6]. Par ailleurs, nous avons constaté que la co-administration de LL-E7 et de LL-IL-12 améliorait significativement la réponse immune spécifique d'antigène [7].…”

Live genetically modified bacteria as drug delivery tools: at the doorstep of a new pharmacology?

“…Streptococcus gordonii [6] and Lactobacillus zeae [7] have also been used to deliver single chain antibodies. In addition, L. lactis has been found to drive the expression of IL-12, a potent immune stimulator [8].…”