Suppression of cytotoxic T lymphocyte activity by 2,3,7,8-tetrachlorodibenzo-p-dioxin occurs in vivo, but not in vitro, and is independent of corticosterone elevation

Heat shock protein (HSP) preparations derived from cancer cells and virus-infected cells have been shown previously to elicit cancer-specific or virus-specific immunity. The immunogenicity of HSP preparations has been attributed to peptides associated with the HSPs. The studies reported here demonstrate that immunogenic HSP–peptide complexes can also be reconstituted in vitro. The studies show that (a) complexes of hsp70 or gp96 HSP molecules with a variety of synthetic peptides can be generated in vitro; (b) the binding of HSPs with peptides is specific in that a number of other proteins tested do not bind synthetic peptides under the conditions in which gp96 molecules do; (c) HSP–peptide complexes reconstituted in vitro are immunologically active, as tested by their ability to elicit antitumor immunity and specific CD8+ cytolytic T lymphocyte response; and (d) synthetic peptides reconstituted in vitro with gp96 are capable of being taken up and re-presented by macrophage in the same manner as gp96– peptides complexes generated in vivo. These observations demonstrate that HSPs are CD8+ T cell response–eliciting adjuvants.

Download Full-text

Anthrax Toxin-Mediated Delivery In Vivo and In Vitro of a Cytotoxic T-Lymphocyte Epitope from Ovalbumin

Infection and Immunity ◽

10.1128/iai.66.2.615-619.1998 ◽

1998 ◽

Vol 66 (2) ◽

pp. 615-619 ◽

Cited By ~ 40

Author(s):

Jimmy D. Ballard ◽

Amy M. Doling ◽

Kathryn Beauregard ◽

R. John Collier ◽

Michael N. Starnbach

Keyword(s):

Fusion Protein ◽

T Lymphocyte ◽

Self Assembly ◽

Protective Antigen ◽

Cytotoxic T Lymphocyte ◽

Ex Vivo ◽

Lethal Factor ◽

Anthrax Toxin

ABSTRACT We reported earlier that a nontoxic form of anthrax toxin was capable of delivering a cytotoxic T-lymphocyte (CTL) epitope in vivo, such that a specific CTL response was primed against the epitope. The epitope, of bacterial origin, was fused to an N-terminal fragment (LFn) from the lethal-factor component of the toxin, and the fusion protein was injected, together with the protective antigen (PA) component, into BALB/c mice. Here we report that PA plus LFn is capable of delivering a different epitope—OVA257–264 from ovalbumin. Delivery was accomplished in a different mouse haplotype,H-2Kb and occurred in vitro as well as in vivo. An OVA257–264-specific CTL clone, GA-4, recognized EL-4 cells treated in vitro with PA plus as little as 30 fmol of the LFn-OVA257–264 fusion protein. PA mutants attenuated in toxin self-assembly or translocation were inactive, implying that the role of PA in epitope delivery is the same as that in toxin action. Also, we showed that OVA257–264-specific CTL could be induced to proliferate by incubation with splenocytes treated with PA plus LFn-OVA257–264. These findings imply that PA-LFn may serve as a general delivery vehicle for CTL epitopes in vivo and as a safe, efficient tool for the ex vivo expansion of patient-derived CTL for use in adoptive immunotherapy.

Download Full-text

Accelerated tumor growth in mice deficient in DNAM-1 receptor

Journal of Experimental Medicine ◽

10.1084/jem.20081611 ◽

2008 ◽

Vol 205 (13) ◽

pp. 2959-2964 ◽

Cited By ~ 155

Author(s):

Akiko Iguchi-Manaka ◽

Hirayasu Kai ◽

Yumi Yamashita ◽

Kai Shibata ◽

Satoko Tahara-Hanaoka ◽

...

Keyword(s):

T Lymphocyte ◽

Nk Cell ◽

Cytotoxic T Lymphocyte ◽

Immune Surveillance ◽

Tumor Development ◽

Wild Type ◽

Human And Mouse ◽

Deficient Mice

Since the identification of ligands for human and mouse DNAM-1, emerging evidence has suggested that DNAM-1 plays an important role in the T cell– and natural killer (NK) cell–mediated recognition and lysis of tumor cells. However, it remains undetermined whether DNAM-1 is involved in tumor immune surveillance in vivo. We addressed this question by using DNAM-1–deficient mice. DNAM-1–deficient cytotoxic T lymphocyte (CTL) and NK cells showed significantly less cytotoxic activity against DNAM-1 ligand-expressing tumors in vitro than wild-type (WT) cells. The methylcholanthrene (MCA)-induced fibrosarcoma cell line Meth A expressed the DNAM-1 ligand CD155, and DNAM-1–deficient mice showed increased tumor development and mortality after transplantation of Meth A cells. Moreover, the DNAM-1–deficient mice developed significantly more DNAM-1 ligand-expressing fibrosarcoma and papilloma cells in response to the chemical carcinogens MCA and 7,12-dimethylbenz[a]anthracene (DMBA), respectively, than did WT mice. These results indicate that DNAM-1 plays an important role in immune surveillance of tumor development.

Download Full-text