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Recombinant vs Standard Influenza Vaccine in Adults With Severe Obesity: A Randomized Clinical Trial.

BACKGROUND: Individuals with severe obesity are at increased risk of severe influenza and may have impaired immune responses to vaccination. Recombinant influenza vaccine (RIV) may provide enhanced protection compared with egg-based standard-dose influenza vaccine (SD), but data in this high-risk population are limited. METHODS: The AP-HP FLUO trial (NCT05409612) was an open-label, randomized clinical trial conducted in 15 centers in France (November 2022-March 2023) with 6 months of follow-up. Adults with BMI &#x2265;35 kg/m2 were randomized 1:1 to receive RIV or SD, using minimization by center, age (<50 vs &#x2265;50 years), and BMI (<40 vs &#x2265;40 kg/m2). The primary outcome was the ratio (RIV/SD) of geometric mean hemagglutinin-inhibition (HAI) titers (GMTs) for 4 influenza strains 28 days after vaccination. Safety and reactogenicity were also assessed. RESULTS: A total of 206 participants were included (104 RIV, 102 SD). Median age was 50 years, 60.2% were women, and median BMI was 41.0 kg/m2. At Day 28, GMT ratios favored RIV for A/H1N1 (1.6; 95% CI, 1.1-2.3), A/H3N2 (2.0; 95% CI, 1.3-3.2), and B/Yamagata (1.3; 95% CI, 1.0-1.8), but not for B/Victoria (0.9; 95% CI, 0.6-1.3). The effect did not vary significantly across the different age and BMI groups. By Day 180, titers did not differ significantly. Reactogenicity and safety profiles were similar between groups. CONCLUSIONS: In adults with severe obesity, RIV elicited stronger short-term humoral immune responses than an egg-based standard-dose vaccine, suggesting potential additional benefit for influenza prevention in this vulnerable population.

Humans

Pilot studies on recombinant cold-adapted live type A and B influenza virus vaccines.

Recombinant live attenuated type A and B influenza virus vaccines derived from standardized cold-adapted parent strains were given singly and in combination to volunteers. The vaccine viruses were well tolerated, functioned as good antigens, and failed to spread to intimate household contacts. Thirty-nine isolates that were recovered after a single passage in humans appeared genetically stable. The results of histopathologic studies in ferrets encourage development of an animal model for attenuation of the virus.

Animals

Serum SRH antibody level as a measure of the immunity against natural and artificial A/Victoria/3/75 infections.

A natural influenza A/Victoria/3/75 outbreak occurred in two communities where part of the residents had been vaccinated with a live recombinant vaccine strain, the RIT 4025 strain (A/Scotland/840/74 serotype). Using the single radial hemolysis technique to measure the antibody level, a relationship was established between the rate of infection and the pre-epidemic serum antibody titer. The higher the pre-epidemic antibody titer, the lower the rate of infection and illness. The protective titer 50% (PT 50) against infection was equal to 26.7 mm2. The same calculation was applied to a population of placebo recipients and RIT 4025 vaccinees challenged with a virulent A/Victoria/3/75 strain. Although the number of volunteers was much smaller, the same correlation was found for the infection detected by a significant antibody rise and for confirmed illness.

Antibodies, Viral

Emerging techniques of CRISPR/Cas system in antiviral therapy and diagnostics: Applications, limitations, and translational perspectives.

The CRISPR/Cas (clustered regularly interspaced short palindromic repeats) system is a versatile technology for developing antiviral medicines and editing viral genomes in both diagnostics and vaccine synthesis. Emerging insights into class 2 effectors, such as Cas9, Cas12, and Cas13, which target viral DNA and RNA, have revolutionized vaccines against viruses such as HIV, HPV, HBV, and EBV. Innovative diagnostic techniques such as SHERLOCK, DETECTR, and FELUDA have demonstrated system's diversity and accuracy in detecting the virus markers, supporting clinical decision-making, indicating adaptability and precision of CRISPR. This review critically evaluates CRISPR's role in RNA editing, emphasizing its importance for functional genomics and development of recombinant vaccines. Translational challenges are critically discussed, including off-target effects, delivery limitations, and ethical issues, for which unique approaches such as high-fidelity Cas variants, non-viral delivery systems, and bioethical frameworks are evaluated to address these limitations. This review also covers other social implications, such as accessibility and biosecurity risks, associated with CRISPR technologies Collectively, these advances underscore the transformative potential of CRISPR technologies in shaping next-generation antiviral diagnostics and therapeutics.

CRISPR-Cas Systems

Development of a recombinant goose parvovirus VP2 neutralizing epitope-containing region vaccine adjuvanted with IL-2 and FliC for enhanced immune responses and protection against challenge.

Gosling plague (GP), caused by goose parvovirus (GPV), is a highly contagious and fatal viral disease. Vaccination is essential for disease prevention; however, conventional attenuated and inactivated vaccines have several limitations. Genetically engineered vaccines based on defined antigenic regions represent a promising alternative strategy. This study aimed to identify neutralizing epitope-containing regions within the GPV VP2 protein and develop effective recombinant vaccines. The GPV VP2 protein was divided into 11 overlapping fragments, and the anchored periplasmic expression (APEx) bacterial display system combined with flow cytometry (FCM) was used for antigenic region screening. GPV VP2-specific single-domain antibodies (VHHs) were further applied to identify neutralizing epitope-containing regions. Six neutralizing epitope-containing regions were identified and linked together to construct the VP2M recombinant antigen. The VP, VP2M, interleukin-2 (IL-2), and flagellin (FliC) genes were inserted into prokaryotic and eukaryotic expression vectors to generate protein and DNA vaccines. Three-day-old goslings were randomly assigned into 15 experimental groups for immunization. Immune responses were evaluated by measuring anti-GPV antibody levels, IgG, IgM, and IgA production, IFN-&#x3b3; levels, immune-related gene expression, splenocyte proliferation, neutralizing activity, and protective efficacy against GPV challenge. The results showed that vaccines containing neutralizing epitope-containing regions induced stronger immune responses than control vaccines. Vaccinated groups exhibited increased anti-GPV antibody levels, IgG, IgM, IgA production, IFN-&#x3b3; levels, immune-related gene expression, and splenocyte proliferation. Following GPV challenge, VP2M-based vaccines significantly reduced viral genome copies in the bursa of Fabricius, spleen, thymus, and intestinal tissues, accompanied by decreased histopathological lesions based on semi-quantitative scoring. Furthermore, the protective efficacy exceeded 50% in vaccines without adjuvants and reached 90% in groups containing combined IL-2 and FliC adjuvants. In conclusion, this study identifies novel neutralizing epitope-containing regions within GPV VP2 and provides a potential strategy for developing safe and effective recombinant vaccines against GP infection.

GP

A/New Jersey/76 influenza vaccine trial in seronegative schoolchildren: comparison of a subunit vaccine with a whole-virus vaccine.

In the present vaccination trial, 202 seronegative schoolchildren comprising both sexes and aged 11 to 12 years were vaccinated i.m. in the upper arm with either the subunit vaccine at a dosage of 600 CCA or 200 CCA or with a whole-virus vaccine at a dosage of 200 CCA, using the double-blind procedure. Both vaccines were prepared from the strain A/New Jersey/76 (x 53a-recombinant). The vaccination was followed four weeks later by a booster injection. In tests of local and systemic reactogenicity, it was found that at both dosages the subunit vaccine caused a low frequency of minor adverse reactions. The whole-virus vaccine was marked by a significantly higher rate of adverse reactions, whether of the local or systemic variety. The whole-virus vaccine had, however, a higher immunogenicity than the subunit vaccine, and due to the relatively high rate of adverse reactions it causes, it is not recommended for the vaccination of seronegative children. Because of its low reactogenicity, the subunit vaccine can be given at higher dosage, and it is a matter for consideration whether a better antibody response might not result from two booster injections.

Antibodies, Viral

Influenza vaccination with live-attenuated and inactivated virus-vaccines during an outbreak of disease.

Immunization procedures with live attenuated and inactivated vaccines were carried out on a group of young recruits at the beginning of an outbreak of infection due to an A/Victoria/3/75-related virus strain, which occurred in February 1977 in a military camp. A retrospective investigation on protection from clinical influenza was then performed in order to investigate whether immunization with live virus vaccines, administered at the beginning of an epidemic, could provide early protection from the disease. In the course of the two weeks following vaccination, laboratory-confirmed clinical influenza cases occurred in 4 subjects among the 110 volunteers of the control group which received placebo, and in 8, 7 and 4 subjects respectively of the 3 groups of about 125 individuals, each of which received one of the following vaccine preparations: (a), live attenuated A/Victoria/3/75 influenza virus oral vaccine, grown on chick embryo kidney culture; (b), live attenuated nasal vaccine, a recombinant of A/Puerto Rico/8/34 with A/Victoria/3/75 virus; and (c), inactivated A/Victoria/3/75 virus intramuscular vaccine. These data do not support the hypothesis that, during an epidemic of infection, early protection from clinical influenza can be achieved through immunization with live attenuated or inactivated influenza virus vaccines, in spite of the high immunizing capability of the vaccine preparations.

Adolescent

Recombinant WRL 105 strain live attenuated influenza vaccine. Immunogenicity, reactivity, and transmissibility.

The immunogenicity, reactivity, and transmissibility of recombinant WRL 105 (H3N2) (A/Okuda/57XA/Finland/4/74) strain live attenuated influenza virus vaccine were studied in adult male volunteers in a residential community in rural England. Thirteen volunteers received a single dose of 10(7.0) E.I.D.50 recombinant WRL 105 vaccine administered as nose drops, and twelve volunteers received placebo. Nine (82%) of eleven volunteers with initial antibody titres of less than or equal to 1/96 showed a significant antibody response to vaccination, but there was no evidence of transmission of vaccine virus to those who received placebo. The incidence and nature of reactions were similar in those who received vaccine and placebo. The vaccine was shown to confer protection against natural infection with a strain exhibition antigenic characteristics equivalent to those of A/Scotland/840/74.

Administration, Intranasal

Use of shotgun immunoproteomics for the development of protein vaccines against Edwardsiella piscicida.

Edwardsiella piscicida is an important emerging pathogen in various cultured fish species. This study aimed to identify immunogenic E. piscicida proteins and evaluate these antigens as protein vaccines for use in aquaculture. Shotgun immunoproteomics using anti-E. piscicida serum from rainbow trout (Oncorhynchus mykiss) and channel catfish (Ictalurus punctatus) (&#x2640;)&#xa0;&#xd7;&#xa0;blue catfish (Ictalurus furcatus) (&#x2642;) hybrids inoculated with formalin-killed whole-bacteria preparations identified 36 candidate immunogenic E. piscicida proteins. The chaparonin GroEL, the glycine 2TM zipper domain-containing protein (GlyZip), and coproporphyrinogen-III oxidase (COPIII) were used to orally (PO) and intra-coelomically (IC) immunize Chinook salmon (Oncorhynchus tshawytscha). Fish IC vaccinated with either GlyZip or COPIII demonstrated a slight, but non-significant, improvement in survival post-challenge with E. piscicida S11-285. Surprisingly, fish IC or PO vaccinated with GroEL displayed an anti-protective effect (RPS&#xa0;=&#xa0;-184&#xa0;% and RPS&#xa0;=&#xa0;-76&#xa0;%, respectively) against subsequent challenge. All IC vaccinated fish generated a strong specific antibody response against the immunizing protein, and sham vaccinated fish challenged with E. piscicida S11-285 generated a significantly higher specific antibody response to the GroEL and GlyZip proteins than negative control fish, suggesting that shotgun immunoproteomics was effective for detection of immunogenic bacterial proteins that can stimulate humoral immune responses in the host fish.

Animals

Persistence of influenza serum antibodies in humans following immunization with a bivalent A/Victoria and A/New Jersey vaccine.

The persistence of serum antibodies 1 year after immunization with a bivalent vaccine containing recombinant viruses that were antigenically identical with A/Victoria/3/75 (H3N2) and A/New Jersey/8/76 (Hsw1N1) viruses was measured in 128 persons aged 18 to 65 years. Serum samples were tested with the hemagglutination inhibition assay against the two vaccine antigens and against A/Texas/1/77 (H3N2) and A/USSR/90/77 (H1N1) viruses. Prior to vaccination 56% and 79% of the participants had been found to be seronegative to A/Victoria and A/New Jersey antigens respectively; the geometric mean antibody titres were low (1:5 to 1:11) except in persons aged 51 to 65 years, whose mean titre of antibody to the A/New Jersey antigen was 1:23, and persons aged 26 to 35 years, whose mean titre of antibody to the A/USSR antigen was 1:25. By 3 weeks after vaccination 85% of the seronegative persons had a fourfold or greater rise in titres of antibodies to the viruses in the vaccine, and 70% had a fourfold increase in titre of antibody to the A/Texas antigen. Of the persons aged 26 to 35 years (seronegative and seropositive) 68% had a fourfold or greater increase in titre of antibody to the A/USSR antigen. There was no change in the mean titres of 19 unvaccinated control subjects during the observation period. At 6 and 12 months after vaccination the titres of antibodies to the A/Victoria and A/New Jersey antigens had declined moderately in all age groups from those observed 3 weeks after vaccination. The rate of decline was similar for the various antibodies except that to the A/USSR antigen in persons 26 to 35 years of age, in whom the decline was much slower.

Adolescent

A plasmid-associated immunoglobulin-binding protein in Acinetobacter baumannii.

BACKGROUND: Acinetobacter baumannii is a critical global health threat due to multidrug resistance and high mortality. Although antimicrobial resistance mechanisms are well characterised, the virulence determinants that drive severe infections remain poorly understood. METHODS: We screened 89 carbapenem-resistant clinical isolates of A. baumannii for virulence in animal infection models and combined comparative genomics with functional assays to identify virulence factors. An immunoglobulin-binding protein from A. baumannii (ImbA) encoded on the type D plasmid was selected and characterised. Protein-immunoglobulin interactions were analysed by pull-down and biolayer interferometry. Additional ImbA inhibition of IgG-Fc&#x3b3; receptor binding by flow cytometry were tested. Protective efficacy was evaluated in mice using vaccination or anti-ImbA antibodies. FINDINGS: A type D plasmid was consistently linked to high virulence in clinical isolates. The deletion of plasmid-encoded ImbA attenuated virulence. ImbA bound murine IgA and IgG with high affinity. The binding to the Fc region of IgG disrupted IgG-Fc&#x3b3; receptor interactions. Vaccination with recombinant ImbA improved survival and reduced bacterial dissemination in female mice with anti-ImbA antibodies partially protecting against lethal infection. Bacterial burdens in the blood were reduced in treated groups. INTERPRETATION: Our study demonstrates ImbA as an unrecognised plasmid-encoded virulence factor in A. baumannii. By intercepting host immunoglobulins, ImbA drives immune evasion and hypervirulence. Blocking ImbA by vaccination and antibody therapy restored host defence and improved outcomes in female mice, highlighting ImbA as a non-antibiotic therapeutic target with potential against multidrug-resistant A. baumannii. FUNDING: Bio&Medical Technology Development Program of the National Research Foundation (NRF), funded by the Korean government (MSIT) (No. RS-2023-00219213); Korea Research Institute of Bioscience and Biotechnology (KRIBB) Research Initiative Program.

Animals

Preparation-conditioned changes of the antigenicity of influenza virus neuraminidases.

The influenza virus strains A/Sing/1/57 (H2N2), A/Bel/42 (H0N1) and A/Bel/42 (HO)-A/Sing/1/57 (N2) were treated with bromelain under reducing conditions and with reducing agent alone, and the antigenicity of the neuraminidase (NA) of intact virus and of the split products was tested comparatively. It was found that the antigenicity of NA was influenced quantitatively and qualitatively by the preparation procedure. Antineuraminidase (AN) antibodies obtained after vaccination of guinea pigs with intact virus and with split products differed in their cross-reactivity with heterologous neuraminidases. In several cases, the quantity of AN antibody formation depended on the hemagglutinin (HA) dose present in the vaccines. The N2 NA on the recombinant virus was significantly more sensitive to treatment with reducing agent than was the N2 NA on the parent virus. AN antibodies directed against N2 NA on the recombinant differed qualitatively from that directed against N2 NA of parent virus. The results warrant the conclusion that the antigenicity of isolated NA or of NA on recombinant virus can differ from that of the NA on intact homologous virus and that such alterations could influence the determination of antigenic relationship between neuraminidases.

Animals

Relationship of genotype of recombinants of influenza A/Hong Kong/68-ts-1[E]virus used as live virus vaccines to virulence in humans.

Influenza A/Hong Kong/68-ts-1[E] virus is a temperature-sensitive mutant developed for use as a live virus vaccine (B. R. Murphy, E. G. Chalhub, S. R. Nusinoff, J. Kasel, and R. M. Chanock, J. Infect. Dis. 128:479--487, 1973). This virus and temperature-sensitive recombinants derived by mating it with A/Udorn/72, A/Georgia/74, or A/Victoria/75 wild-type virus have been administered to volunteers in clinical trials on the assumption that the ts-1[E] temperature-sensitive genetic lesions on a polymerase gene (P3) and on the nucleoprotein gene (NP) would determine a satisfactory and reproducible level of attentuation regardless of the genetic constitution of ts-1[E] recombinants at other loci (B. R. Murphy, D. D. Richman, S. B. Spring, and R. M. Chanock, Postgrad. Med. 52:381--388, 1976). In this paper, the parental origin of genes in the ts-1[E] recombinants was determined by using the technique of polyacrylamide gel electrophoresis of virion ribonucleic acid segments in the presence of a denaturing agent (urea). When tested in individuals who lacked immunity to hemagglutinin antigen, attenuation of the ts-1[E] recombinants appeared to correlate with inheritance of the ts-1[E] temperature-sensitive genes at the P3 and NP loci and with the level of preinfection neuraminidase immunity. There was no evidence that other genes from the ts-1[E] donor virus played a role in attenuation.

Genes, Viral

Protection from natural infection after live influenza virus immunization in an open population.

Live attenuated influenza vaccine containing the recombinant of A/Victoria/3/75 with A/PR/8/34 virus was administered to healthy adults in a field trial aimed at evaluating protection provided by immunization. The study was designed to measure the effect of vaccination on absenteeism from respiratory disease during a natural influenza epidemic. A total of 2115 male employees of the public transport service of Rome volunteered to participate in the trial, 1050 and 1065 receiving vaccine and placebo respectively, in a randomized blind fashion. Vaccination procedure was completed by the end of December 1976. A small-sized outbreak of influenza, due to a viral strain antigenically homologous to the vaccine, occurred during the month of February 1977. Analysis of absenteeism data, classified according to medical certificate, indicated that morbidity from respiratory disease was reduced in vaccinees compared with controls during the epidemic month; the rate of increase of morbidity compared with that of the preceding month was then three times lower in vaccinees than in controls and the difference in absenteeism between the two groups greatly exceeded the ordinary fluctuation that was observed during non-epidemic periods.

Adult