KBMA Listeria monocytogenes is an effective vector for DC-mediated induction of antitumor immunity
Mojca Skoberne, … , Dirk G. Brockstedt, Nina Bhardwaj
Mojca Skoberne, … , Dirk G. Brockstedt, Nina Bhardwaj
Published November 6, 2008
Citation Information: J Clin Invest. 2008;118(12):3990-4001. https://doi.org/10.1172/JCI31350.
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Research Article

KBMA Listeria monocytogenes is an effective vector for DC-mediated induction of antitumor immunity

Abstract

Vaccine strategies that utilize human DCs to enhance antitumor immunity have yet to realize their full potential. Approaches that optimally target a spectrum of antigens to DCs are urgently needed. Here we report the development of a platform for loading DCs with antigen. It is based on killed but metabolically active (KBMA) recombinant Listeria monocytogenes and facilitates both antigen delivery and maturation of human DCs. Highly attenuated KBMA L. monocytogenes were engineered to express an epitope of the melanoma-associated antigen MelanA/Mart-1 that is recognized by human CD8+ T cells when presented by the MHC class I molecule HLA-A*0201. The engineered KBMA L. monocytogenes induced human DC upregulation of costimulatory molecules and secretion of pro-Th1 cytokines and type I interferons, leading to effective priming of Mart-1–specific human CD8+ T cells and lysis of patient-derived melanoma cells. KBMA L. monocytogenes expressing full-length NY-ESO-1 protein, another melanoma-associated antigen, delivered the antigen for presentation by MHC class I and class II molecules independent of the MHC haplotype of the DC donor. A mouse therapeutic tumor model was used to show that KBMA L. monocytogenes efficiently targeted APCs in vivo to induce protective antitumor responses. Together, our data demonstrate that KBMA L. monocytogenes may be a powerful platform that can both deliver recombinant antigen to DCs for presentation and provide a potent DC-maturation stimulus, making it a potential cancer vaccine candidate.

Authors

Mojca Skoberne, Alice Yewdall, Keith S. Bahjat, Emmanuelle Godefroy, Peter Lauer, Edward Lemmens, Weiqun Liu, Will Luckett, Meredith Leong, Thomas W. Dubensky, Dirk G. Brockstedt, Nina Bhardwaj

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Figure 2

KBMA L. monocytogenes activate moDCs.

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KBMA L. monocytogenes activate moDCs. (A) DCs were infected with L. ...
(A) DCs were infected with L. monocytogenes strains, stained with antibodies to L. monocytogenes (green), phalloidin (red), and DAPI (blue). Visualization of polymerized actin and colocalization with the bacteria (yellow) confirms the presence of bacteria within the cytoplasm. Scale bar: 10 μm. (B and C) DCs were infected with live (L), HK, or KBMA L. monocytogenes. Unstimulated or DCs, exposed to LPS or MC, were used as controls. Expression of DC-maturation markers for a typical donor is shown (gray bars, MOI 1; black bars, MOI 10) (B). Results of multiple donors are shown in C (MOI 10). (D and E) Presence of cytokines (D) and chemokines (E) was measured by ELISA (gray bars, MOI 1; black bars, MOI 10). (F) DCs were infected at MOI 10 (WT, L) or MOI 200 (ΔLLO, HK, and KBMA L. monocytogenes). Immature, LPS, or poly I:C–stimulated DCs were used as controls. IFN-α in supernatants was measured. (G) DCs were infected with live, HK, or KBMA L. monocytogenes and left untreated or stimulated with LPS or MC. CCR7 was measured by flow cytometry after 40 hours. (H) DCs were infected with live or KBMA L. monocytogenes. CCR7 was measured at indicated time points. Numbers in parentheses indicate MOI used for infection. Nonstimulated or LPS-stimulated DCs were used as controls. In C, F, and G, values from individual donors (dots), mean values (lines), and Student’s t test P values are shown. In A, B, D, E, and H, a representative experiment of at least 3 performed is shown. In D and E, error bars represent SD of triplicate culture wells.