Poly(lactic acid)-poly(ethylene glycol) nanoparticles provide sustained delivery of a Chlamydia trachomatis recombinant MOMP peptide and potentiate systemic adaptive immune responses in mice.

PLA-PEG [poly(lactic acid)-poly (ethylene glycol)], a biodegradable copolymer, is underexploited for vaccine delivery although it exhibits enhanced biocompatibility and slow release immune-potentiating properties. We document here successful encapsulation of M278, a Chlamydia trachomatis MOMP (major outer-membrane protein) peptide, within PLA-PEG nanoparticles by size (~73-100nm), zeta potential (-16 mV), smooth morphology, encapsulation efficiency (~60%), slow release pattern, and non-toxicity to macrophages. Immunization of mice with encapsulated M278 elicited higher M278-specific T-cell cytokines [Th1 (IFN-γ, IL-2), Th17 (IL-17)] and antibodies [Th1 (IgG2a), Th2 (IgG1, IgG2b)] compared to bare M278. Encapsulated-M278 mouse serum inhibited Chlamydia infectivity of macrophages, with a concomitant transcriptional down-regulation of MOMP, its cognate TLR2 and CD80 co-stimulatory molecule. Collectively, encapsulated M278 potentiated crucial adaptive immune responses, which are required by a vaccine candidate for protective immunity against Chlamydia. Our data highlight PLA-PEG's potential for vaccines, which resides in its slow release and potentiating effects to bolster immune responses. This study highlights the potential of a PLA-PEG-based nanoparticle formulation containing a major outer membrane protein of chlamydia trachomatis in inducing a sustained enhanced immune response, paving the way to the development of a vaccination strategy against this infection.

Dixit S ，Singh SR ，Yilma AN ，Agee RD 2nd ，Taha M ，Dennis VA ... -  《-》

The Chlamydia M278 Major Outer Membrane Peptide Encapsulated in the Poly(lactic acid)-Poly(ethylene glycol) Nanoparticulate Self-Adjuvanting Delivery System Protects Mice Against a Chlamydia muridarum Genital Tract Challenge by Stimulating Robust Systemic

Verma R ，Sahu R ，Dixit S ，Duncan SA ，Giambartolomei GH ，Singh SR ，Dennis VA ... -  《Frontiers in Immunology》

Chlamydia trachomatis recombinant MOMP encapsulated in PLGA nanoparticles triggers primarily T helper 1 cellular and antibody immune responses in mice: a desirable candidate nanovaccine.

Fairley SJ ，Singh SR ，Yilma AN ，Waffo AB ，Subbarayan P ，Dixit S ，Taha MA ，Cambridge CD ，Dennis VA ... -  《International Journal of Nanomedicine》

Encapsulation of Recombinant MOMP in Extended-Releasing PLGA 85:15 Nanoparticles Confer Protective Immunity Against a Chlamydia muridarum Genital Challenge and Re-Challenge.

Recently we reported the immune-potentiating capacity of a Chlamydia nanovaccine (PLGA-rMOMP) comprising rMOMP (recombinant major outer membrane protein) encapsulated in extended-releasing PLGA [poly (D, L-lactide-co-glycolide) (85:15)] nanoparticles. Here we hypothesized that PLGA-rMOMP would bolster immune-effector mechanisms to confer protective efficacy in mice against a Chlamydia muridarum genital challenge and re-challenge. Female BALB/c mice received three immunizations, either subcutaneously (SC) or intranasally (IN), before receiving an intravaginal challenge with C. muridarum on day 49 and a re-challenge on day 170. Both the SC and IN immunization routes protected mice against genital challenge with enhanced protection after a re-challenge, especially in the SC mice. The nanovaccine induced robust antigen-specific Th1 (IFN-γ, IL-2) and IL-17 cytokines plus CD4+ proliferating T-cells and memory (CD44high CD62Lhigh) and effector (CD44high CD62Llow) phenotypes in immunized mice. Parallel induction of antigen-specific systemic and mucosal Th1 (IgG2a, IgG2b), Th2 (IgG1), and IgA antibodies were also noted. Importantly, immunized mice produced highly functional Th1 avidity and serum antibodies that neutralized C. muridarum infectivity of McCoy fibroblasts in-vitro that correlated with their respective protection levels. The SC, rather than the IN immunization route, triggered higher cellular and humoral immune effectors that improved mice protection against genital C. muridarum. We report for the first time that the extended-releasing PLGA 85:15 encapsulated rMOMP nanovaccine confers protective immunity in mice against genital Chlamydia and advances the potential towards acquiring a nano-based Chlamydia vaccine.

Sahu R ，Dixit S ，Verma R ，Duncan SA ，Smith L ，Giambartolomei GH ，Singh SR ，Dennis VA ... -  《Frontiers in Immunology》

Caveolin-mediated endocytosis of the Chlamydia M278 outer membrane peptide encapsulated in poly(lactic acid)-Poly(ethylene glycol) nanoparticles by mouse primary dendritic cells enhances specific immune effectors mediated by MHC class II and CD4(+) T cell

We previously developed a Chlamydia trachomatis nanovaccine (PPM) by encapsulating a chlamydial M278 peptide within poly(lactic acid)-poly(ethylene glycol) biodegradable nanoparticles that immunopotentiated Chlamydia-specific immune effector responses in mice. Herein, we investigated the mechanistic interactions of PPM with mouse bone marrow-derived dendritic cells (DCs) for its uptake, trafficking, and T cell activation. Our results reveal that PPM triggered enhanced expression of effector cytokines and chemokines, surface activation markers (Cd1d2, Fcgr1), pathogen-sensing receptors (TLR2, Nod1), co-stimulatory (CD40, CD80, CD86) and MHC class I and II molecules. Co-culturing of PPM-primed DCs with T cells from C. muridarum vaccinated mice yielded an increase in Chlamydia-specific immune effector responses including CD3+ lymphoproliferation, CD3+CD4+ IFN-γ-secreting cells along with CD3+CD4+ memory (CD44high and CD62Lhigh) and effector (CD44high and CD62Llow) phenotypes. Intracellular trafficking analyses revealed an intense expression and colocalization of PPM predominantly in endosomes. PPM also upregulated the transcriptional and protein expression of the endocytic mediator, caveolin-1 in DCs. More importantly, the specific inhibition of caveolin-1 led to decreased expression of PPM-induced cytokines and co-stimulatory molecules. Our investigation shows that PPM provided enhancement of uptake, probably by exploiting the caveolin-mediated endocytosis pathway, endosomal processing, and MHC II presentation to immunopotentiate Chlamydia-specific immune effector responses mediated by CD4+ T cells.

Dixit S ，Sahu R ，Verma R ，Duncan S ，Giambartolomei GH ，Singh SR ，Dennis VA ... -  《-》