M2e-Based Influenza Vaccines with Nucleoprotein: A Review

Discovery of conserved antigens for universal influenza vaccines warrants solutions to a number of concerns pertinent to the currently licensed influenza vaccines, such as annual reformulation and mismatching with the circulating subtypes. The latter causes low vaccine efficacies, and hence leads to severe disease complications and high hospitalization rates among susceptible and immunocompromised individuals. A universal influenza vaccine ensures cross-protection against all influenza subtypes due to the presence of conserved epitopes that are found in the majority of, if not all, influenza types and subtypes, e.g., influenza matrix protein 2 ectodomain (M2e) and nucleoprotein (NP). Despite its relatively low immunogenicity, influenza M2e has been proven to induce humoral responses in human recipients. Influenza NP, on the other hand, promotes remarkable anti-influenza T-cell responses. Additionally, NP subunits are able to assemble into particles which can be further exploited as an adjuvant carrier for M2e peptide. Practically, the T-cell immunodominance of NP can be transferred to M2e when it is fused and expressed as a chimeric protein in heterologous hosts such as Escherichia coli without compromising the antigenicity. Given the ability of NP-M2e fusion protein in inducing cross-protective anti-influenza cell-mediated and humoral immunity, its potential as a universal influenza vaccine is therefore worth further exploration.

Download Full-text

Comparisons of the Humoral and Cellular Immune Responses Induced by Live Attenuated Influenza Vaccine and Inactivated Influenza Vaccine in Adults

Clinical and Vaccine Immunology ◽

10.1128/cvi.00414-16 ◽

2016 ◽

Vol 24 (1) ◽

Cited By ~ 42

Author(s):

Daniel F. Hoft ◽

Kathleen R. Lottenbach ◽

Azra Blazevic ◽

Aldin Turan ◽

Tamara P. Blevins ◽

...

Keyword(s):

Influenza Virus ◽

T Cell ◽

Young Children ◽

Influenza Vaccine ◽

T Cell Responses ◽

Influenza Vaccines ◽

Secretory Iga ◽

Cell Responses ◽

Live Attenuated Influenza Vaccine ◽

Cellular Immune

ABSTRACT Both live attenuated influenza vaccines (LAIV) and inactivated influenza vaccines (IIV) induce protective immunity against influenza. There is evidence that LAIV induces superior protection in children, whereas IIV may induce superior protection in adults. The immune mechanisms responsible for these differences have not been identified. We previously compared LAIV and IIV in young children of 6 to 36 months of age, and we demonstrated that while both induced similar hemagglutination inhibition (HAI) antibody responses, only LAIV induced significant increases in T cell responses. In the present study, 37 healthy adult subjects of 18 to 49 years of age were randomized to receive seasonal influenza vaccination with LAIV or IIV. Influenza virus-specific HAI, T cell, and secretory IgA (sIgA) responses were studied pre- and postvaccination. In contrast to the responses seen in young children, LAIV induced only minimal increases in serum HAI responses in adults, which were significantly lower than the responses induced by IIV. Both LAIV and IIV similarly induced only transient T cell responses to replication-competent whole virus in adults. In contrast, influenza virus-specific sIgA responses were induced more strongly by LAIV than by IIV. Our previous studies suggest that LAIV may be more protective than IIV in young children not previously exposed to influenza virus or influenza vaccines due to increased vaccine-induced T cell and/or sIgA responses. Our current work suggests that in adults with extensive and partially cross-reactive preexisting influenza immunity, LAIV boosting of sIgA responses to hemagglutinin (HA) and non-HA antigenic targets expressed by circulating influenza virus strains may be an important additional mechanism of vaccine-induced immunity.

Download Full-text

Effect of an adenovirus-vectored universal influenza virus vaccine on pulmonary pathophysiology in a mouse model

Journal of Virology ◽

10.1128/jvi.02359-20 ◽

2021 ◽

Author(s):

Santosh Dhakal ◽

Jeffrey Loube ◽

Julia A. Misplon ◽

Chia-Yun Lo ◽

Patrick Creisher ◽

...

Keyword(s):

Influenza Virus ◽

T Cell ◽

Pulmonary Inflammation ◽

T Cell Responses ◽

Cd8 T Cell ◽

T Cell Immunity ◽

Influenza Vaccines ◽

Cell Responses ◽

Cell Immunity ◽

Universal Influenza Vaccine

Current influenza vaccines, live-attenuated or inactivated, do not protect against antigenically novel influenza A viruses (IAVs) of pandemic potential, which has driven interest in development of universal influenza vaccines. Universal influenza vaccine candidates targeting highly conserved antigens of IAV nucleoprotein (NP) are promising as vaccines that induce T cell immunity, but concerns have been raised about the safety of inducing robust CD8 T cell responses in the lungs. Using a mouse model, we systematically evaluated effects of recombinant adenovirus vectors (rAd) expressing IAV NP (A/NP-rAd) or influenza B virus (IBV) NP (B/NP-rAd) on pulmonary inflammation and function after vaccination and following live IAV challenge. After A/NP-rAd or B/NP-rAd vaccination, female mice exhibited robust systemic and pulmonary vaccine-specific B cell and T cell responses and experienced no morbidity (e.g., body mass loss). Both in vivo pulmonary function testing and lung histopathology scoring revealed minimal adverse effects of intranasal rAd vaccination compared with unvaccinated mice. After IAV challenge, A/NP-rAd vaccinated mice experienced significantly less morbidity, had lower pulmonary virus titers, and developed less pulmonary inflammation than unvaccinated or B/NP-rAd vaccinated mice. Based on analysis of pulmonary physiology using detailed testing not previously applied to the question of T cell damage, mice protected by vaccination also had better lung function than controls. Results provide evidence that in this model, adenoviral universal influenza vaccine does not damage pulmonary tissue. In addition, adaptive immunity, in particular T-cell immunity in the lungs, does not cause damage when restimulated, but instead mitigates pulmonary damage following IAV infection. Importance: Respiratory viruses can emerge and spread rapidly, before vaccines are available. It would be a tremendous advance to use vaccines that protect against whole categories of viruses, such as universal influenza vaccines, without the need to predict which virus will emerge. Nucleoprotein (NP) of influenza virus provides a target conserved among strains and is a dominant T-cell target. In animals, vaccination to NP generates powerful T cell immunity and long-lasting protection against diverse influenza strains. Concerns have been raised, but not evaluated experimentally, that potent local T-cell responses might damage the lungs. We analyzed lung function in detail in the setting of such a vaccination. Despite CD8 T-cell responses in the lungs, lungs were not damaged and functioned normally after vaccination alone and were protected upon subsequent infection. This precedent provides important support for vaccines based on T-cell-mediated protection, currently being considered for both influenza and SARS-CoV-2 vaccines.

Download Full-text

Influenza H1 Mosaic Hemagglutinin Vaccine Induces Broad Immunity and Protection in Mice

Vaccines ◽

10.3390/vaccines7040195 ◽

2019 ◽

Vol 7 (4) ◽

pp. 195 ◽

Cited By ~ 1

Author(s):

Brigette N. Corder ◽

Brianna L. Bullard ◽

Jennifer L. DeBeauchamp ◽

Natalia A. Ilyushina ◽

Richard J. Webby ◽

...

Keyword(s):

T Cell ◽

Influenza Vaccine ◽

Protective Immunity ◽

Influenza A ◽

T Cell Responses ◽

Antibody Responses ◽

T Cell Epitopes ◽

Wild Type ◽

Cell Responses ◽

Universal Influenza Vaccine

Annually, influenza A virus (IAV) infects ~5–10% of adults and 20–30% of children worldwide. The primary resource to protect against infection is by vaccination. However, vaccination only induces strain-specific and transient immunity. Vaccine strategies that induce cross-protective immunity against the broad diversity of IAV are needed. Here we developed and tested a novel mosaic H1 HA immunogen. The mosaic immunogen was optimized in silico to include the most potential B and T cell epitopes (PBTE) across a diverse population of human H1 IAV. Phylogenetic analysis showed that the mosaic HA localizes towards the non-pandemic 2009 strains which encompasses the broadest diversity in the H1 IAV population. We compared the mosaic H1 immunogen to wild-type HA immunogens and the commercial inactivated influenza vaccine, Fluzone. When analyzed by ELISA, the mosaic immunogen induced stronger antibody responses against all four diverse H1 HA proteins. When analyzing T cell responses, again the mosaic immunogen induced stronger cellular immunity against all 4 diverse HA strains. Not only was the magnitude of T cell responses strongest in mosaic immunized mice, the number of epitopes recognized was also greater. The mosaic vaccinated mice showed strong cross-protection against challenges with three divergent IAV strains. These data show that the mosaic immunogen induces strong cross-protective immunity and should be investigated further as a universal influenza vaccine.

Download Full-text

Faculty Opinions recommendation of Live and inactivated influenza vaccines induce similar humoral responses, but only live vaccines induce diverse T-cell responses in young children.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.13335992.14702101 ◽

2011 ◽

Author(s):

Eugene Shapiro

Keyword(s):

T Cell ◽

Young Children ◽

T Cell Responses ◽

Influenza Vaccines ◽

Live Vaccines ◽

Cell Responses ◽

Humoral Responses

Download Full-text

Live and Inactivated Influenza Vaccines Induce Similar Humoral Responses, but Only Live Vaccines Induce Diverse T-Cell Responses in Young Children

The Journal of Infectious Diseases ◽

10.1093/infdis/jir436 ◽

2011 ◽

Vol 204 (6) ◽

pp. 845-853 ◽

Cited By ~ 193

Author(s):

Daniel F. Hoft ◽

Elizabeth Babusis ◽

Shewangizaw Worku ◽

Charles T. Spencer ◽

Kathleen Lottenbach ◽

...

Keyword(s):

T Cell ◽

Young Children ◽

T Cell Responses ◽

Influenza Vaccines ◽

Live Vaccines ◽

Cell Responses ◽

Humoral Responses

Download Full-text

The Dual-Antigen Ad5 COVID-19 Vaccine Delivered as an Intranasal Plus Subcutaneous Prime Elicits Th1 Dominant T-Cell and Humoral Responses in CD-1 Mice

10.1101/2021.03.22.436476 ◽

2021 ◽

Author(s):

Adrian Rice ◽

Mohit Verma ◽

Annie Shin ◽

Lise Zakin ◽

Peter Sieling ◽

...

Keyword(s):

T Cell ◽

Oral Delivery ◽

Surface Display ◽

T Cell Responses ◽

Human Adenovirus ◽

Cell Surface Display ◽

Mhc I ◽

Cell Responses ◽

Serotype 5 ◽

Humoral Responses

In response to the need for an efficacious, thermally-stable COVID-19 vaccine that can elicit both humoral and cell-mediated T-cell responses, we have developed a dual-antigen human adenovirus serotype 5 (hAd5) COVID-19 vaccine in formulations suitable for subcutaneous (SC), intranasal (IN), or oral delivery. The vaccine expresses both the SARS-CoV-2 spike (S) and nucleocapsid (N) proteins using an hAd5 platform with E1, E2b, and E3 sequences deleted; hAd5(E1-, E2b-, E3-); that is effective even in the presence of hAd5 immunity. In the vaccine, S is modified (S-Fusion) for enhanced cell surface display to elicit humoral responses and N is modified with an Enhanced T-cell Stimulation Domain (N-ETSD) to direct N to the endosomal/lysosomal pathway to increase MHC I and II presentation. Initial studies using subcutaneous (SC) prime and SC boost vaccination of CD-1 mice demonstrated that the hAd5 S-Fusion + N-ETSD vaccine elicits T-helper cell 1 (Th1) dominant T-cell and humoral responses to both S and N. We then compared SC to IN prime vaccination with either an SC or IN boost post-SC prime and an IN boost after IN prime. These studies reveal that IN prime/IN boost is as effective at generating Th1 dominant humoral responses to both S and N as the other combinations, but that the SC prime with either an IN or SC boost elicits greater T cell responses. In a third study to assess the power of the two routes of delivery when used together, we used a combined SC plus IN prime with or without a boost and found the combined prime alone to be as effective as the combined prime with either an SC or IN boost in generating both humoral and T-cell responses. The findings here in CD-1 mice demonstrate that combined SC and IN prime-only delivery has the potential to provide broad immunity, including mucosal immunity, against SARS-CoV-2 and supports further testing of this delivery approach in additional animal models and clinical trials.

Download Full-text