scholarly journals Differential Immunogenicity and Protective Efficacy Elicited by MTO- and DMT-Adjuvanted CMFO Subunit Vaccines against Mycobacterium tuberculosis Infection

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Nadeem Ullah ◽  
Ling Hao ◽  
Yaqi Wu ◽  
Yandi Zhang ◽  
Qing Lei ◽  
...  

Tuberculosis (TB) remains a major and global problem of public health. An effective TB subunit vaccine is urgently needed. Proper selection of the delivery system for the vaccine is crucial for inducing an appropriate immune response tailored to control the target pathogen. In this study, we compared the immunogenicity and protective efficacy of CMFO subunit vaccines against primary progressive TB in two different adjuvant systems: the MTO oil-in-water (O/W) emulsion composed of monophosphoryl lipid A (MPL), trehalose-6,60-dibehenate (TDB), and oil in water emulsion MF59 and the DMT liposome containing dimethyldioctadecylammonium bromide (DDA), monophosphoryl lipid A (MPL), and trehalose-6,60-dibehenate (TDB). Our results demonstrated that the DMT-adjuvanted CMFO could confer more significant protection against M. tuberculosis infection than the CMFO/MTO did in mice. In particular, the adjuvant DMT showed a stronger ability than the O/W emulsion to adjuvant CMFO subunit vaccine and enhanced protection, attributed to elicit Th1-biased responses, strong Th1/Th17 cytokine responses, and IFN-γ+ or IL-2+ T cell responses. Therefore, our findings demonstrate that the liposome delivery system shows more effectiveness to adjuvant TB subunit vaccine than O/W emulsion and highlight the importance of adjuvant formulation for the better efficacy of a protein vaccine.

Vaccines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 494 ◽  
Author(s):  
Teerasit Techawiwattanaboon ◽  
Christophe Barnier-Quer ◽  
Tanapat Palaga ◽  
Alain Jacquet ◽  
Nicolas Collin ◽  
...  

Leptospirosis vaccines with higher potency and reduced adverse effects are needed for human use. The carboxyl terminal domain of leptospiral immunoglobulin like protein A (LigAc) is currently the most promising candidate antigen for leptospirosis subunit vaccine. However, LigAc-based vaccines were unable to confer sterilizing immunity against Leptospira infection in animal models. Several factors including antigen properties, adjuvant, delivery system, and administration route need optimization to maximize vaccine efficacy. Our previous report demonstrated protective effects of the recombinant LigAc (rLigAc) formulated with liposome-based adjuvant, called LMQ (neutral liposome combined with monophosphoryl lipid A and Quillaja saponaria fraction 21) in hamsters. This study aimed to evaluate the impact of two commonly used administration routes, intramuscular (IM) and subcutaneous (SC), on immunogenicity and protective efficacy of rLigAc-LMQ administrated three times at 2-week interval. Two IM vaccinations triggered significantly higher levels of total anti-rLigAc IgG than two SC injections. However, comparable IgG titers and IgG2/IgG1 ratio was observed for both routes after the third immunization. The route of vaccine administration did not influence the survival rate (60%) and renal colonization against lethal Leptospira challenge. Importantly, the kidneys of IM group showed no pathological lesions while the SC group showed mild damage. In conclusion, IM vaccination with rLigAc-LMQ not only elicited faster antibody production but also protected from kidney damage following leptospiral infection better than SC immunization. However, both tested routes did not influence protective efficacy in terms of survival rate and the level of renal colonization.


2017 ◽  
Vol 24 (3) ◽  
Author(s):  
Katharina Richard ◽  
Barbara J. Mann ◽  
Aiping Qin ◽  
Eileen M. Barry ◽  
Robert K. Ernst ◽  
...  

ABSTRACT Francisella tularensis, a bacterial biothreat agent, has no approved vaccine in the United States. Previously, we showed that incorporating lysates from partially attenuated F. tularensis LVS or fully virulent F. tularensis Schu S4 strains into catanionic surfactant vesicle (V) nanoparticles (LVS-V and Schu S4-V, respectively) protected fully against F. tularensis LVS intraperitoneal (i.p.) challenge in mice. However, we achieved only partial protection against F. tularensis Schu S4 intranasal (i.n.) challenge, even when employing heterologous prime-boost immunization strategies. We now extend these findings to show that both LVS-V and Schu S4-V immunization (i.p./i.p.) elicited similarly high titers of anti-F. tularensis IgG and that the titers could be further increased by adding monophosphoryl lipid A (MPL), a nontoxic Toll-like receptor 4 (TLR4) adjuvant that is included in several U.S. FDA-approved vaccines. LVS-V+MPL immune sera also detected more F. tularensis antigens than LVS-V immune sera and, after passive transfer to naive mice, significantly delayed the time to death against F. tularensis Schu S4 subcutaneous (s.c.) but not i.n. challenge. Active immunization with LVS-V+MPL (i.p./i.p.) also increased the frequency of gamma interferon (IFN-γ)-secreting activated helper T cells, IFN-γ production, and the ability of splenocytes to control intramacrophage F. tularensis LVS replication ex vivo. Active LVS-V+MPL immunization via heterologous routes (i.p./i.n.) significantly elevated IgA and IgG levels in bronchoalveolar lavage fluid and significantly enhanced protection against i.n. F. tularensis Schu S4 challenge (to ∼60%). These data represent a significant step in the development of a subunit vaccine against the highly virulent type A strains.


2005 ◽  
Vol 73 (1) ◽  
pp. 250-257 ◽  
Author(s):  
Avi-Hai Hovav ◽  
Yolanta Fishman ◽  
Herve Bercovier

ABSTRACT In this study, we examined the immunogenicity and protective efficacy of six immunodominant Mycobacterium tuberculosis recombinant antigens (85B, 38kDa, ESAT-6, CFP21, Mtb8.4, and 16kDa) in a multivalent vaccine preparation (6Ag). Gamma interferon (IFN-γ) and monophosphoryl lipid A-trehalose dicorynomycolate (Ribi) adjuvant systems were used separately or in combination for immunization with the recombinant antigens. Our results demonstrate that immunization of mice with Ribi emulsified antigens in the presence of IFN-γ (Ribi+6Ag+IFN-γ) resulted after challenge with a virulent M. tuberculosis strain in a significant reduction in the CFU counts that was comparable to that achieved with the BCG vaccine (∼0.9-log protection). Antigen-specific immunoglobulin G (IgG) titers in the Ribi+6Ag+IFN-γ-immunized mice were lower than in mice immunized with Ribi+6Ag and were oriented toward a Th1-type response, as confirmed by elevated IgG2a levels. In addition, splenocyte proliferation, IFN-γ secretion, and NO production were significantly higher in splenocytes derived from Ribi+6Ag+IFN-γ-immunized mice, whereas IL-10 secretion was decreased. These findings confirm the induction of a strong cellular immunity in the vaccinated mice that correlates well with their enhanced resistance to M. tuberculosis. The adjuvant effect of IFN-γ was dose dependent. A dose of 5 μg of IFN-γ per mouse per immunization gave optimal protection, whereas lower or higher amounts (0.5 or 50 μg/ mouse) of IFN-γ failed to enhance protection.


Vaccines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 131
Author(s):  
Christoph M. Janitzek ◽  
Philip H. R. Carlsen ◽  
Susan Thrane ◽  
Vijansh M. Khanna ◽  
Virginie Jakob ◽  
...  

Capsid-like particle (CLP) displays can be used to enhance the immunogenicity of vaccine antigens, but a better understanding of how CLP vaccines are best formulated and delivered is needed. This study compared the humoral immune responses in mice elicited against two different vaccine antigens (a bacterial protein and a viral peptide) delivered on an AP205 CLP platform using six different adjuvant formulations. In comparison to antibody responses obtained after immunization with the unadjuvanted CLP vaccine, three of the adjuvant systems (neutral liposomes/monophosphoryl lipid A/quillaja saponaria 21, squalene-in-water emulsion, and monophosphoryl lipid A) caused significantly increased antibody levels, whereas formulation with the three other adjuvants (aluminum hydroxide, cationic liposomes, and cationic microparticles) resulted in similar or even decreased antibody responses. When delivering the soluble bacterial protein in a squalene-in-water emulsion, 4-log lower IgG levels were obtained compared to when the protein was delivered on CLPs without the adjuvant. The AP205 CLP platform promoted induction of both IgG1 and IgG2 subclasses, which could be skewed towards a higher production of IgG1 (aluminum hydroxide). Compared to other routes, intramuscular administration elicited the highest IgG levels. These results indicate that the effect of the external adjuvant does not always synergize with the adjuvant effect of the CLP display, which underscores the need for empirical testing of different extrinsic adjuvants.


1997 ◽  
Vol 25 (2) ◽  
pp. 274S-274S
Author(s):  
STEPHEN THOMPSON ◽  
MARIE DAVIES ◽  
TERRY O'NEILL ◽  
FINN HOLDING ◽  
ALISON MANN ◽  
...  

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