Tetanus toxin L chain is processed by major histocompatibility complex class I and class II pathways and recognized by CD8+ or CD4+ T lymphocytes

Engineering Memory T Cells as a platform for Long-Term Enzyme Replacement Therapy in Lysosomal Storage Disorders

Enzymopathy disorders are the result of missing or defective enzymes. Amongst these enzymopathies, mucopolysaccharidosis type I, is a rare genetic lysosomal storage disorder caused by mutations in the gene encoding alpha-L-iduronidase (IDUA), ultimately causes toxic build-up of glycosaminoglycans (GAGs). There is currently no cure and standard treatments provide insufficient relief to the skeletal structure and central nervous system (CNS). Human memory T cells (Tm) migrate throughout the body's tissues and can persist for years, making them an attractive approach for cellular-based, systemic enzyme replacement therapy. Here, we tested genetically engineered, IDUA-expressing Tm as a cellular therapy in an immunodeficient mouse model of MPS I. Our results demonstrate that a single dose of engineered Tm leads to detectable IDUA enzyme levels in the blood for up to 22 weeks and reduced urinary GAG excretion. Furthermore, engineered Tm take up residence in nearly all tested tissues, producing IDUA and leading to metabolic correction of GAG levels in the heart, lung, liver, spleen, kidney, bone marrow, and the CNS. Our study indicates that genetically engineered Tm holds great promise as a platform for cellular-based enzyme replacement therapy for the treatment of mucopolysaccharidosis type I and potentially many other enzymopathies and protein deficiencies.

Isolation and characterization of new human carrier peptides from two important vaccine immunogens

In the preparation of glycoconjugate vaccines in clinical practice, two highly immunogenic carrier proteins, CRM₁₉₇ and tetanus toxoid (TT), are predominantly conjugated with the capsular polysaccharides (CPSs) of bacterial pathogens. In addition, TT has long been used as an effective vaccine to prevent tetanus. While these carrier proteins play an important role in immunogenicity and vaccine design alike, their defined human major histocompatibility complex class II (MHCII) T cell epitopes are inadequately characterized. In this current work, we use mass spectrometry to identify the peptides from these carrier proteins that are naturally processed and presented by human B cells via MHCII pathway. The MHCII-presented peptides are screened for their T cell stimulation using primary CD4+ T cells from four healthy adult donors. These combined methods reveal a subset of eleven CD4+ T cell epitopes that proliferate and stimulate human T cells with diverse MHCII allelic repertoire. Six of these peptides stand out as potential immunodominant epitopes by responding in three or more donors. Additionally, we provide evidence of these natural epitopes eliciting more significant T cell responses in donors than previously published TT peptides selected from T cell epitope screening. This study serves toward understanding carrier protein immune responses and thus enables the use of these peptides in developing novel knowledge-based vaccines to combat persisting problems in glycoconjugate vaccine design.

Synthetic Cannabinoid-Induced Immunosuppression Augments Cerebellar Dysfunction in Tetanus-Toxin Treated Mice

Synthetic cannabinoids are one of most abused new psychoactive substances. The recreational use of abused drug has aroused serious concerns about the consequences of these drugs on infection. However, the effects of synthetic cannabinoid on resistance to tetanus toxin are not fully understood yet. In the present study, we aimed to determine if the administration of synthetic cannabinoids increase the susceptibility to tetanus toxin-induced motor behavioral deficit and functional changes in cerebellar neurons in mice. Furthermore, we measured T lymphocytes marker levels, such as CD8 and CD4 which against tetanus toxin. JWH-210 administration decreased expression levels of T cell activators including cluster of differentiation (CD) 3ε, CD3γ, CD74p31, and CD74p41. In addition, we demonstrated that JWH-210 induced motor impairment and decrement of vesicle-associated membrane proteins 2 levels in the cerebellum of mice treated with tetanus toxin. Furthermore, cerebellar glutamatergic neuronal homeostasis was hampered by JWH-210 administration, as evidenced by increased glutamate concentration levels in the cerebellum. These results suggest that JWH-210 may increase the vulnerability to tetanus toxin via the regulation of immune function.

Vaccine therapy with dendritic cells transfected with Il13ra2 mRNA for glioma in mice

OBJECT

The Il13ra2 gene is often overexpressed in brain tumors, making Il13ra2 one of the vaccine targets for immunotherapy of glioma. In this study, using a mouse glioma model, the authors tested the hypothesis that vaccination using dendritic cells transfected with Il13ra2 mRNA induces strong immunological antitumor effects.

METHODS

A plasmid was constructed for transduction of the mRNAs transcribed in vitro into dendritic cells. This was done to transport the intracellular protein efficiently into major histocompatibility complex class II compartments by adding a late endosomal/lysosomal sorting signal to the Il13ra2 gene. The dendritic cells transfected with this Il13ra2 mRNA were injected intraperitoneally into the mouse glioma model at 3 and 10 days after tumor cell implantation. The antitumor effects were estimated based on the survival rate, results of histological analysis, and immunohistochemical findings for immune cells.

RESULTS

The group treated by vaccination therapy with dendritic cells transfected with Il13ra2 mRNA survived significantly longer than did the control groups. Immunohistochemical analysis revealed that greater numbers of T lymphocytes containing CD4+ and CD8+ T cells were found in the group vaccinated with dendritic cells transfected with Il13ra2 mRNA.

CONCLUSIONS

These results demonstrate the therapeutic potential of vaccination with dendritic cells transfected with Il13ra2 mRNA for the treatment of malignant glioma.

Expansion of immunoglobulin autoreactive T-helper cells in multiple myeloma

Activation and expansion of T helper (Th) cells followed by regulation of activation are essential to the generation of immune responses while limiting concomitant autoreactivity. In order to characterize T cells reactive towards myeloma-derived monoclonal immunoglobulin (mIg), an autologous coculture assay for single-cell analysis of mIg-responding cells was developed. When cultured with dendritic cells loaded with mIg, CD4(+) Th cells from patients with progressing multiple myeloma (MM) showed a proliferative MHC class II-dependent response. CD8(+) T-cell reactivity and Th1 activation were consistently low or absent, and Th2 and regulatory cytokines were expressed. The presence of such non-Th1 CD4(+) T cells in peripheral blood was independent of treatment status, while the frequencies of responding cells varied between patients and reached the same order of magnitude as those measured for tetanus toxoid-specific Th memory cells. Furthermore, investigations of T-cell subpopulations indicated a possible regulatory role on the mIg responsiveness mediated by suppressive CD25(high)FOXP3(+)CD4(+) T cells. It is proposed from the present results that a predominant in vivo activation of non-Th1 mIg-reactive CD4(+) T cells constitute an Ig-dependent autoregulatory mechanism in human MM, with possible tumor growth supporting or permissive effects.

Antitumor effects of vaccination with dendritic cells transfected with modified receptor for hyaluronan-mediated motility mRNA in a mouse glioma model

OBJECT

The receptor for hyaluronan-mediated motility (RHAMM) is frequently overexpressed in brain tumors and was recently identified as an immunogenic antigen by using serological screening of cDNA expression libraries. In this study, which was conducted using a mouse glioma model, the authors tested the hypothesis that vaccination with dendritic cells transfected with RHAMM mRNA induces strong immunological antitumor effects.

METHODS

The authors constructed a plasmid for transduction of the mRNAs transcribed in vitro into dendritic cells, which were then used to transport the intracellular protein RHAMM efficiently into major histocompatibility complex class II compartments by adding a late endosomal-lysosomal sorting signal to the RHAMM gene. The dendritic cells transfected with this RHAMM mRNA were injected intraperitoneally into the mouse glioma model 3 and 10 days after tumor cell implantation. The antitumor effects of the vaccine were estimated by the survival rate, histological analysis, and immunohistochemical findings for immune cells. Mice in the group treated by vaccination therapy with dendritic cells transfected with RHAMM mRNA survived significantly longer than those in the control groups. Immunohistochemical analysis revealed that greater numbers of T lymphocytes containing T cells activated by CD4+, CD8+, and CD25+ were found in the group vaccinated with dendritic cells transfected with RHAMM mRNA.

CONCLUSIONS

These results demonstrate the therapeutic potential of vaccination with dendritic cells transfected with RHAMM mRNA for the treatment of malignant glioma.