This study presents the background, rationale and method of action of Biovacc-19, a candidate vaccine for corona virus disease 2019 (Covid-19), now in advanced preclinical development, which has already passed the first acute toxicity testing. Unlike conventionally developed vaccines, Biovacc-19’s method of operation is upon nonhuman-like (NHL) epitopes in 21.6% of the composition of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)’s spike protein, which displays distinct distributed charge including the presence of a charged furin-like cleavage site. The logic of the design of the vaccine is explained, which starts with empirical analysis of the aetiology of SARS-CoV-2. Mistaken assumptions about SARS-CoV-2’s aetiology risk creating ineffective or actively harmful vaccines, including the risk of antibody-dependent enhancement. Such problems in vaccine design are illustrated from past experience in the human immunodeficiency viruses domain. We propose that the dual effect general method of action of this chimeric virus’s spike, including receptor binding domain, includes membrane components other than the angiotensin-converting enzyme 2 receptor, which explains clinical evidence of its infectivity and pathogenicity. We show the nonreceptor dependent phagocytic general method of action to be specifically related to cumulative charge from insertions placed on the SARS-CoV-2 spike surface in positions to bind efficiently by salt bridge formations; and from blasting the spike we display the NHL epitopes from which Biovacc-19 has been down-selected.

Caenorhabditis elegans is a free-living nematode that resides in soil and typically feeds on bacteria. We postulate that haematophagic C. elegans could provide a model to evaluate vaccine responses to intestinal proteins from hematophagous nematode parasites, such as Necator americanus. Human erythrocytes, fluorescently labelled with tetramethylrhodamine succinimidyl ester, demonstrated a stable bright emission and facilitated visualization of feeding events with fluorescent microscopy. C. elegans were observed feeding on erythrocytes and were shown to rupture red blood cells upon capture to release and ingest their contents. In addition, C. elegans survived equally on a diet of erythrocytes. There was no statistically significant difference in survival when compared with a diet of Escherichia coli OP50. The enzymes responsible for the digestion and detoxification of haem and haemoglobin, which are key components of the hookworm vaccine, were found in the C. elegans intestine. These findings support our postulate that free-living nematodes could provide a model for the assessment of neutralizing antibodies to current and future hematophagous parasite vaccine candidates.

The extent of sequence diversity among the genes encoding 10 antigens (Tp1–10) known to be recognized by CD8+ T lymphocytes from cattle immune to Theileria parva was analysed. The sequences were derived from parasites in 23 buffalo-derived cell lines, three cattle-derived isolates and one cloned cell line obtained from a buffalo-derived stabilate. The results revealed substantial variation among the antigens through sequence diversity. The greatest nucleotide and amino acid diversity were observed in Tp1, Tp2 and Tp9. Tp5 and Tp7 showed the least amount of allelic diversity, and Tp5, Tp6 and Tp7 had the lowest levels of protein diversity. Tp6 was the most conserved protein; only a single non-synonymous substitution was found in all obtained sequences. The ratio of non-synonymous: synonymous substitutions varied from 0.84 (Tp1) to 0.04 (Tp6). Apart from Tp2 and Tp9, we observed no variation in the other defined CD8+ T cell epitopes (Tp4, 5, 7 and 8), indicating that epitope variation is not a universal feature of T. parva antigens. In addition to providing markers that can be used to examine the diversity in T. parva populations, the results highlight the potential for using conserved antigens to develop vaccines that provide broad protection against T. parva.

Annual H3N2 subtype influenza outbreaks in Guangdong, China are a severe public health issue and require ongoing monitoring of emerging viral variants. The variation and evolution of haemagglutinin (HA) and neuraminidase (NA) genes of influenza isolates from Guangdong during 2007–2011 and others from GenBank were analysed using Lasergene 7.1 and MEGA 5.05, and serological analysis of antigens was determined by haemagglutination inhibition (HI). Susceptibility to antiviral drugs was correlated with genetic mutations. Phylogenetic analysis and alignment of HA and NA genes were performed on 18 Guangdong isolates and 26 global reference strains. The non-synonymous (dN) evolutionary rate of HA1 was 3·13 times that of HA2. Compared with the A/Perth/16/2009 vaccine HA gene, homologies of Guangdong isolates were between 98·8–99·7% and 98·0–98·4% in 2009 and 2010, respectively. Amino-acid substitutions were found in five epitopes of HA1 from Guangdong isolates between 2007 and 2011, especially in epitopes B (N160K) and D (K174R/N). The K189E/N/Q and T228A mutations in the receptor-binding site (RBS) occurred in the 2010 strains, which affected the antigenicity of HA1. The antigenicity of the epidemic H3N2 isolates in 2010 was somewhat different from that of A/Perth/16/2009. The Guangdong H3N2 isolates were determined to be oseltamivir-resistant with IC50 of 0·396±0·085 nmol/l (n=17) and zanamivir-resistant with IC50 of 0·477±0·149 nmol/l (n=18). Variations were present in epitopes B and D, two sites in the RBS and two glycosylation sites in the Guangdong H3N2 HA1 gene. The majority of the Guangdong H3N2 isolates were sensitive to oseltamivir and zanamivir. Compared to the World Health Organization 2012 vaccine strains, Guangdong H3N2 strains varied genetically and antigenically to some degree.

Monoclonal antibodies raised against antigens present in the excretions/secretions (E/S) of larval Trichinella spiralis, polyclonal antibodies raised against E/S and antisera from rabbits and pigs infected with T. spiralis were used in conjunction with immunocytochemical techniques to detect antigens in sections of muscle from mice that had been infected with T. spiralis for 15 or 30 days. The antibodies recognized epitopes in the stichocytes, on the surface of the cuticle, in the lumen of the oesophagus and in the lumen of the intestine of encysted larvae. Monoclonal antibodies 7C2C5 and 1H7 and the polyclonal antibodies recognized epitopes in the cavity occupied by the larva, in the cytoplasm of the nurse cell, and in the hypertrophic nuclei of the nurse cell, but did not recognize material in the smaller nuclei of the nurse cell, in the cyst wall or in the surrounding muscle. Monoclonals 3B2E6 and 1D11G8B2, which recognized epitopes in the stichocytes and on the surface of the cuticle of the larvae, gave negative results with the cytoplasm and nuclei of the nurse cell. A polyclonal antibody raised against Trichuris suis recognized epitopes in the muscle and hypodermis of encysted T. spiralis but gave negative results with material in the nurse cell and nurse cell nuclei. The possibility that the antigen detected in the cytoplasm and nuclei of the nurse cell is produced by the stichocytes of the nematode and that it is controlling genes of the altered muscle fibre, either directly or indirectly, is discussed.

Food allergies or food intolerances affect nearly everyone at some point. “Food Allergy” refers to all interactions between molecules derived from the food supply and the immune system. Food allergies can be sub-divided into IgE (Immunoglobulin E) –mediated hypersensitivities and cell mediated hypersensitivities, but in most of the cases is IgE mediated. There has been an increased prevalence of food allergy reactions in the last decade. Approximately 2–3% of adults and 5–7% of children are affected by food allergy. Hen's egg is one of the most common causes of food allergic reactions, particularly in children. The prevalence of egg allergy is about 35% of food allergic children. It usually disappears by age five to seven years, but may sometimes be lifelong. Egg white, which is generally considered more allergenic than egg yolk, has four major allergenic proteins namely, ovomucoid (Gal d 1), ovalbumin (Gal d 2), ovotransferrin (Gal d 3), and lysozyme (Gal d 4) which are defined as immuno dominant proteins of egg white in egg allergic patients. Detailed characterization of the biochemical, immunological and structural properties of the major two allergens of the egg white, the ovalbumin and the ovomucoid have been studied. Studies of the B cell and T cell epitopes of these allergens have been summarized and mechanisms to reduce allergic reactions of these proteins at their molecular level has been evaluated in detail.

Four synthetic peptides which comprise the immunodominant linear epitopes of the EG95 recombinant protein, were investigated for their ability to induce host-protective immunity against Echinococcus granulosus in sheep. Sheep were immunized with either free peptide or peptide conjugated to diphtheria toxoid and challenge infected with E. granulosus eggs. All of the peptides elicited specific antibody, but these did not kill the parasite in in vitro culture assays, nor did the peptides induce protection against challenge infection. In contrast, anti-EG95 antibodies affinity purified against each of the 4 peptides were lethal to the parasite in in vitro culture. These affinity-purified antibodies were shown to contain specific antibody to both peptide and EG95. In in vitro inhibition assays, the peptides did not diminish anti-EG95 antibody binding to EG95 or parasite lysis in oncosphere killing assays. These results suggest that the fine specificities of antibodies raised against the recombinant protein are different to those raised against the peptide immunogens and that the majority of the antibody induced by vaccination with EG95 is raised against conformational determinants.

Cholesteryl ester transfer protein (CETP) plays an important role in plasma lipoprotein metabolism through its ability to transfer cholesteryl ester, triglyceride, and phospholipid between lipoproteins. CETP is a member of a gene family that also includes bactericidal/permeability-increasing protein (BPI). The crystal structure of BPI shows it to be composed of two domains that share a similar structural fold that includes an apolar ligand-binding pocket. As structurally important residues are conserved between BPI and CETP, it is thought that CETP and BPI may have a similar overall conformation. We have previously proposed a model of CETP structure based on the binding characteristics of anti-CETP monoclonal antibodies (mAbs). We now present a refined epitope map of CETP that has been adapted to a structural model of CETP that uses the atomic coordinates of BPI. Four epitopes composed of CETP residues 215–219, 219–223, 223–227, and 444–450, respectively, are predicted to be situated on the external surface of the central β-sheet and a fifth epitope (residues 225–258) on an extended linker that connects the two domains of the molecule. Three other epitopes, residues 317–331, 360–366, and 393–410, would form part of the putative carboxy-terminal β-barrel. The ability of the corresponding mAbs to compete for binding to CETP is consistent with the proximity of the respective epitopes in the model. These results thus provide experimental evidence that is consistent with CETP and BPI having similar surface topologies.

Sera of some patients afflicted with the inflammatory disease myositis contain antibodies of the anti-PL-12 type. A fraction of these polyclonal autoantibodies specifically precipitates the fully matured human tRNAAla bearing the anticodon IGC (PL-12 antigen). Earlier work (Bunn & Mathews, 1987, Science 238:116–119) had shown that the epitopes are located entirely within the anticodon stem-loop of the tRNAAla. Here we demonstrate that human anti-tRNAAla autoantibodies immunoprecipitate a synthetic polyribonucleotide containing inosine (I) and N1-methylinosine (m1I) separated by 2 nt as in the anticodon stem-loop of human tRNAAla. The shortest polyribonucleotide that can be immunoprecipitated corresponds to the pentanucleotide IpGpCpm1IpUp, which corresponds to part of the anticodon loop of human tRNAAla and lacks the stem-loop structure. The efficiency of immunoprecipitation was about four times greater with longer polyribonucleotides capable of forming a stem-loop structure, and was abolished by altering the relative positions of I and m1I within the synthetic polynucleotide. Synthetic oligodeoxyribonucleotide analogs of the tRNAAla stem-loop, containing the sequence dIpdGdCdm1Ip, are not antigenic. Our results show that human anti-tRNAAla autoantibodies selectively recognize chemical details of modified nucleotides (the 6-keto group of inosine-34 and the 6-keto group and the N1-methyl groups of N1-methylinosine-37) within an anticodon loop structure of a tRNA molecule. We also describe the chemical synthesis of the phosphoramidite derivatives corresponding to N1-methylinosine and N1-methyl-2′-deoxyinosine for use in the automatic chemical synthesis of oligonucleotides containing N1-methylinosine and N1-methyl-2′-deoxyinosine.