Mucosal TLR2-activating protein-based vaccination induces potent pulmonary immunity and protection against SARS-CoV-2 in mice

Current vaccines against SARS-CoV-2 substantially reduce mortality, but protection against infection is less effective. Enhancing immunity in the respiratory tract, via mucosal vaccination, may provide protection against infection and minimise viral spread. We tested a novel subunit vaccine in mice, consisting of SARS-CoV-2 Spike protein with a TLR2-stimulating adjuvant, delivered to mice parenterally or mucosally. Both routes of vaccination induced substantial neutralising antibody (nAb) titres, however, mucosal vaccination uniquely generated anti-Spike IgA, increased nAb in the serum and airways, and increased lung CD4+ T-cell responses. TLR2 is expressed by respiratory epithelia and immune cells. Using TLR2 deficient chimeric mice, we determined that TLR2 expression in either compartment facilitated early innate responses to mucosal vaccination. By contrast, TLR2 on hematopoietic cells was essential for optimal lung-localised, antigen-specific responses. In a K18-hACE2 mice, vaccination provided complete protection against disease and sterilising lung immunity against SARS-CoV-2. These data support mucosal vaccination as a strategy to improve protection in the respiratory tract against SARS-CoV-2 and other respiratory viruses.

SARS-CoV2 variant-specific replicating RNA vaccines protect from disease and pathology and reduce viral shedding following challenge with heterologous SARS-CoV2 variants of concern

Despite mass public health efforts, the SARS-CoV2 pandemic continues as of late-2021 with resurgent case numbers in many parts of the world. The emergence of SARS-CoV2 variants of concern (VoC) and evidence that existing vaccines that were designed to protect from the original strains of SARS-CoV-2 may have reduced potency for protection from infection against these VoC is driving continued development of second generation vaccines that can protect against multiple VoC. In this report, we evaluated an alphavirus-based replicating RNA vaccine expressing Spike proteins from the original SARS-CoV-2 Alpha strain and recent VoCs delivered in vivo via a lipid inorganic nanoparticle. Vaccination of both mice and Syrian Golden hamsters showed that vaccination induced potent neutralizing titers against each homologous VoC but reduced neutralization against heterologous challenges. Vaccinated hamsters challenged with homologous SARS-CoV2 variants exhibited complete protection from infection. In addition, vaccinated hamsters challenged with heterologous SARS-CoV-2 variants exhibited significantly reduced shedding of infectious virus. Our data demonstrate that this vaccine platform elicits significant protective immunity against SARS-CoV2 variants and supports continued development of this platform.

Comparative Evaluation of Immune Responses and Protection of Chitosan Nanoparticles and Oil-Emulsion Adjuvants in Avian Coronavirus Inactivated Vaccines in Chickens

Efficient vaccines are the main strategy to control the avian coronavirus (AvCoV), although several drawbacks related to traditional attenuated and inactivated vaccines have been reported. These counterpoints highlight the importance of developing new alternative vaccines against AvCoV, especially those able to induce long-lasting immune responses. This study evaluated and compared two inactivated vaccines formulated with AvCoV BR-I variants, one composed of chitosan nanoparticles (AvCoV-CS) and the second by Montanide oily adjuvant (AvCoV-O). Both developed vaccines were administered in a single dose or associated with the traditional Mass attenuated vaccine. The AvCoV-CS vaccine administered alone or associated with the Mass vaccine was able to induce strong humoral and cell-mediated immune (CMI) responses and complete protection against IBV virulent infection, wherein single administration was characterized by high IgA antibody levels in the mucosa, whereas when associated with the Mass vaccine, the serum IgG antibody was predominantly observed. On the other hand, single administration of the oily vaccine presented poor humoral and CMI responses and consequently incomplete protection against virulent challenge, but when associated with the Mass vaccine, immune responses were developed, and complete protection against infection was observed. Both of our experimental vaccines were able to induce full protection against virulent IBV challenge. A single dose of AvCoV-CS vaccine was sufficient to achieve complete protection, while AvCoV-O required a previous priming by a Mass strain to complete the protection.

Intranasal HD-Ad vaccine protects the upper and lower respiratory tracts of hACE2 mice against SARS-CoV-2

Background The ongoing COVID-19 pandemic has resulted in 185 million recorded cases and over 4 million deaths worldwide. Several COVID-19 vaccines have been approved for emergency use in humans and are being used in many countries. However, all the approved vaccines are administered by intramuscular injection and this may not prevent upper airway infection or viral transmission. Results Here, we describe a novel, intranasally delivered COVID-19 vaccine based on a helper-dependent adenoviral (HD-Ad) vector. The vaccine (HD-Ad_RBD) produces a soluble secreted form of the receptor binding domain (RBD) of the SARS-CoV-2 spike protein and we show it induced robust mucosal and systemic immunity. Moreover, intranasal immunization of K18-hACE2 mice with HD-Ad_RBD using a prime-boost regimen, resulted in complete protection of the upper respiratory tract against SARS-CoV-2 infection. Conclusion Our approaches provide a powerful platform for constructing highly effective vaccines targeting SARS-CoV-2 and its emerging variants.

FLOT; To Be Treated as a Highly Emetogenic Regimen or a Moderately Emetogenic One? Comparison of the Emetogenic Potential of FLOT versus FOLFOX and TAC Regimens

PurposeThe current study aimed at investigating the efficacy of aprepitant-containing triple antiemetic regimen in FLOT (Fluorouracil+Leucovorin+Oxaliplatin+Docetaxel) recipients as well as the emetogenic potential of FLOT regimen, through comparison of nausea and vomiting rates in a moderately emetogenic chemotherapy, FLOT, and a highly emetogenic chemotherapy recipients.StudyPatients planned to receive one of FLOT, FOLFOX (Fluorouracil+Leucovorin+ Oxaliplatin/moderate-emetic-risk), or TAC (Docetaxel+Doxorubicin+Cyclophosphamide/high-emetic-risk) regimens were recruited. All patients were treated with the same triple antiemetic regimen containing aprepitant.ResultsA total of 165 chemotherapy-naïve patients (52 FLOT recipients) were eligible to enter the study. At the end of day five, “complete response” (primary efficacy endpoint) was achieved by 84.6%, 63.5%, and 61.5% of the FLOT-receiving patients in acute, delayed, and overall phases, respectively. A significant difference was seen among the odds of FLOT recipients and FOLFOX recipients concerning “complete response” achievement in delayed (p=0.014) and overall (p=0.017) phases, “no emesis” in delayed (p=0.018) and overall (p=0.010) phases, also “complete protection” in acute (p=0.023), delayed (p=0.009) and overall (p=0.006) phases; however, the difference between the odds of FLOT recipients and TAC recipients, in relation to achieving these endpoints was insignificant. FLOT group showed significantly faster time-to-antiemetic regimen failure and time-to-first emetic episode in comparison to the FOLFOX group, which was insignificant in comparison to the TAC group.ConclusionAccording to the findings, FLOT has to be considered as a high-emetic-risk regimen. To better management of highly emetogenic regimens, antiemetic guidelines recommend adding olanzapine to aprepitant-containing triple antiemetic regimen besides continuing dexamethasone and olanzapine administration on days 2-4.

Robust IgM responses following intravenous vaccination with Bacille Calmette–Guérin associate with prevention of Mycobacterium tuberculosis infection in macaques

Development of an effective tuberculosis (TB) vaccine has suffered from an incomplete understanding of the correlates of protection against Mycobacterium tuberculosis (Mtb). Intravenous (i.v.) vaccination with Bacille Calmette–Guérin (BCG) provides nearly complete protection against TB in rhesus macaques, but the antibody response it elicits remains incompletely defined. Here we show that i.v. BCG drives superior antibody responses in the plasma and the lungs of rhesus macaques compared to traditional intradermal BCG administration. While i.v. BCG broadly expands antibody titers and functions, IgM titers in the plasma and lungs of immunized macaques are among the strongest markers of reduced bacterial burden. IgM was also enriched in macaques that received protective vaccination with an attenuated strain of Mtb. Finally, an Mtb-specific IgM monoclonal antibody reduced Mtb survival in vitro. Collectively, these data highlight the potential importance of IgM responses as a marker and mediator of protection against TB.

A trimeric NTD and RBD SARS-CoV-2 subunit vaccine induced protective immunity in CAG-hACE2 transgenic mice and rhesus macaques

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to significant public health, economic and social problems. Development of effective vaccines is still a priority to contain the virus and end the global pandemic. In this study, we reported that ReCOV, a recombinant trimeric NTD and RBD two-component SARS-CoV-2 subunit vaccine adjuvanted with BFA03 (an AS03-like squalene adjuvant), induced high levels of neutralizing antibodies against SARS-CoV-2 and the circulating variants in mice, rabbits and rhesus macaques. Notably, two-dose immunizations of ReCOV provided complete protection against challenge with SARS-CoV-2 in hACE2 transgenic mice and rhesus macaques, without observable antibody-dependent enhancement of infection. These results support further clinical development of ReCOV and the vaccine is currently being evaluated in a phase I clinical trial in New Zealand (NCT04818801).

Vaccination of pentivalent, DTP, ADS vaccine for healthy and frequently sick children

Aim. To study the formation of anti-diphtheria post-vaccination immunity in practically healthy, and frequently sick children vaccinated with pentavalent, ADTP, and ADT vaccine.Material and methods. We observed 50 practically healthy and 92 frequently sick children. All children were vaccinated three times with a pentavalent vaccine, as well as revaccination with ADTP and ADT. The formation of specific anti-diphtheria immunity was detected for all children after 6 months, after 1 year, and after 5 years. The results were interpreted according to the final value of the optical density levels of protection: basic from -0,01 to 0,1; full protection -> 0.1; long-term protection -> 1.0.Results and discussion. After 6 months the intensity of post-vaccination immunity in both practically healthy and frequently sick children was the highest: full protection (> 0.1) (45,8%), basic protection (0,01 to 0,1) (31,0%). Statistical significance decreased after a year: full protection (45,8% versus 12,1%, p <0,001), and lack of protection increased (2,6% versus 55,7%, p <0,001), which indicated to the development of unstable immunity, therefore revaccination with ADTP and ADT vaccines were performed. 5 years after revaccination specific immunity tended to increase in both healthy and often-ill children.Conclusion. To create stable and long-term immunity when using “killed” vaccines and toxoids, revaccination vaccinations are required at various times after the course of vaccination for frequently ill children, as indicated by the data of basic and complete protection.