scholarly journals TLR4 Ligands Augment Antigen-Specific CD8+ T Lymphocyte Responses Elicited by a Viral Vaccine Vector

2010 ◽  
Vol 84 (19) ◽  
pp. 10413-10419 ◽  
Author(s):  
Elizabeth G. Rhee ◽  
R. Phelps Kelley ◽  
Isha Agarwal ◽  
Diana M. Lynch ◽  
Annalena La Porte ◽  
...  

ABSTRACT Toll-like receptor (TLR) ligands are critical activators of innate immunity and are being developed as vaccine adjuvants. However, their utility in conjunction with viral vector-based vaccines remains unclear. In this study, we evaluated the impact of a variety of TLR ligands on antigen-specific CD8+ T lymphocyte responses elicited by a recombinant adenovirus serotype 26 (rAd26) vector expressing simian immunodeficiency virus Gag in mice. The TLR3 ligand poly(I:C) suppressed Gag-specific cellular immune responses, whereas the TLR4 ligands lipopolysaccharide and monophosphoryl lipid A substantially augmented the magnitude and functionality of these responses by a MyD88- and TRIF-dependent mechanism. These data demonstrate that TLR ligands can modulate the immunogenicity of viral vaccine vectors both positively and negatively. Moreover, these findings suggest the potential utility of TLR4 ligands as adjuvants for rAd vector-based vaccines.

2019 ◽  
Vol 87 (6) ◽  
Author(s):  
Sakineh Pirahmadi ◽  
Sedigheh Zakeri ◽  
Akram A. Mehrizi ◽  
Navid D. Djadid ◽  
Abbas-Ali Raz ◽  
...  

ABSTRACTPlasmodium falciparumcell-traversal protein for ookinetes and sporozoites (PfCelTOS) is an advanced vaccine candidate that has a crucial role in the traversal of the malaria parasite in both mosquito and mammalian hosts. As recombinant purified proteins are normally poor immunogens, they require to be admixed with an adjuvant(s); therefore, the objective of the present study was to evaluate the capacity of different vaccine adjuvants, monophosphoryl lipid A (MPL), CpG, andQuillaja saponariaMolina fraction 21 (QS-21), alone or in combination (MCQ [MPL/CpG/QS-21]), to enhance the immunogenicity ofEscherichia coli-expressed PfCelTOS in BALB/c mice. This goal was achieved by the assessment of anti-PfCelTOS IgG antibodies (level, titer, IgG isotype profile, avidity, and persistence) and extracellular Th1 cytokines using an enzyme-linked immunosorbent assay (ELISA) on postimmunized BALB/c mouse sera and PfCelTOS-stimulated splenocytes, respectively. Also, an assessment of the transmission-reducing activity (TRA) of anti-PfCelTOS obtained from different vaccine groups was carried out in femaleAnopheles stephensimosquitoes by using a standard membrane feeding assay (SMFA). In comparison to PfCelTOS alone, administration of PfCelTOS with three distinct potent Th1 adjuvants in vaccine mouse groups showed enhancement and improvement of PfCelTOS immunogenicity that generated more bias toward a Th1 response with significantly enhanced titers and avidity of the anti-PfCelTOS responses that could impair ookinete development inA. stephensi. However, immunization of mice with PfCelTOS with MCQ mixture adjuvants resulted in the highest levels of induction of antibody titers, avidity, and inhibitory antibodies in oocyst development (88%/26.7% reductions in intensity/prevalence) inA. stephensi. It could be suggested that adjuvant combinations with different mechanisms stimulate better functional antibody responses than adjuvants individually against challenging diseases such as malaria.


2008 ◽  
Vol 15 (4) ◽  
pp. 691-696 ◽  
Author(s):  
Ralf Geiben-Lynn ◽  
John R. Greenland ◽  
Kwesi Frimpong-Boateng ◽  
Norman L. Letvin

ABSTRACT While a new generation of vaccine vectors has been developed for eliciting cellular immune responses, little is known about the optimal routes for their administration or about the ramifications of the kinetics of in vivo vaccine antigen expression for immunogenicity. We evaluated the kinetics of vaccine antigen expression by real-time in vivo photon imaging and showed dramatic differences in these kinetics using different vectors and different routes of administration. Further, using a gamma interferon enzyme-linked immunospot assay to measure T-lymphocyte immune responses, we observed an association between the kinetics of vaccine antigen expression in vivo and the magnitude of vaccine-elicited memory T-lymphocyte responses. These results highlight the utility of the real-time in vivo photon-imaging technology in evaluating novel immunization strategies and suggest an association between the kinetics of vaccine antigen clearance and the magnitude of vaccine-elicited T-lymphocyte memory immune responses.


2008 ◽  
Vol 82 (10) ◽  
pp. 4844-4852 ◽  
Author(s):  
Jinyan Liu ◽  
Bonnie A. Ewald ◽  
Diana M. Lynch ◽  
Matthew Denholtz ◽  
Peter Abbink ◽  
...  

ABSTRACT Recombinant adenovirus serotype 5 (rAd5) vaccine vectors for human immunodeficiency virus type 1 (HIV-1) and other pathogens have been shown to elicit antigen-specific cellular immune responses. Rare serotype rAd vectors have also been constructed to circumvent preexisting anti-Ad5 immunity and to facilitate the development of novel heterologous rAd prime-boost regimens. Here we show that rAd5, rAd26, and rAd48 vectors elicit qualitatively distinct phenotypes of cellular immune responses in rhesus monkeys and can be combined as potent heterologous prime-boost vaccine regimens. While rAd5-Gag induced primarily gamma interferon-positive (IFN-γ+) and IFN-γ+/tumor necrosis factor alpha+ (TNF-α+) T-lymphocyte responses, rAd26-Gag and rAd48-Gag induced higher proportions of interleukin-2+ (IL-2+) and polyfunctional IFN-γ+/TNF-α+/IL-2+ T-lymphocyte responses. Priming with the rare serotype rAd vectors proved remarkably effective for subsequent boosting with rAd5 vectors. These data demonstrate that the rare serotype rAd vectors elicited T-lymphocyte responses that were phenotypically distinct from those elicited by rAd5 vectors and suggest the functional relevance of polyfunctional CD8+ and CD4+ T-lymphocyte responses. Moreover, qualitative differences in cellular immune responses may prove critical in determining the overall potency of heterologous rAd prime-boost regimens.


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.


PLoS ONE ◽  
2012 ◽  
Vol 7 (7) ◽  
pp. e40745 ◽  
Author(s):  
Juliana Vitoriano-Souza ◽  
Nádia das Dores Moreira ◽  
Andréa Teixeira-Carvalho ◽  
Cláudia Martins Carneiro ◽  
Fernando Augusto Mathias Siqueira ◽  
...  

Vaccines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 744
Author(s):  
Konlavat Siriwattananon ◽  
Suwimon Manopwisedjaroen ◽  
Balamurugan Shanmugaraj ◽  
Eakachai Prompetchara ◽  
Chutitorn Ketloy ◽  
...  

Due to the rapid transmission of the coronavirus disease 2019 (COVID-19) causing serious public health problems and economic burden, the development of effective vaccines is a high priority for controlling the virus spread. Our group has previously demonstrated that the plant-produced receptor-binding domain (RBD) of SARS-CoV-2 fused with Fc of human IgG was capable of eliciting potent neutralizing antibody and cellular immune responses in animal studies, and the immunogenicity could be improved by the addition of an alum adjuvant. Here, we performed a head-to-head comparison of different commercially available adjuvants, including aluminum hydroxide gel (alum), AddaVax (MF59), monophosphoryl lipid A from Salmonella minnesota R595 (mPLA-SM), and polyinosinic-polycytidylic acid (poly(I:C)), in mice by combining them with plant-produced RBD-Fc, and the differences in the immunogenicity of RBD-Fc with different adjuvants were evaluated. The specific antibody responses in terms of total IgG, IgG1, and IgG2a subtypes and neutralizing antibodies, as well as vaccine-specific T-lymphocyte responses, induced by the different tested adjuvants were compared. We observed that all adjuvants tested here induced a high level of total IgG and neutralizing antibodies, but mPLA-SM and poly (I:C) showed the induction of a balanced IgG1 and IgG2a (Th2/Th1) immune response. Further, poly (I:C) significantly increased the frequency of IFN-γ-expressing cells compared with control, whereas no significant difference was observed between the adjuvanted groups. This data revealed the adjuvants’ role in enhancing the immune response of RBD-Fc vaccination and the immune profiles elicited by different adjuvants, which could prove helpful for the rational development of next-generation SARS-CoV-2 RBD-Fc subunit vaccines. However, additional research is essential to further investigate the efficacy and safety of this vaccine formulation before clinical trials.


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