High neutralizing antibody levels against SARS-CoV-2 Omicron after UB-612 booster vaccination

The highly transmissible Omicron variant has caused high rates of breakthrough infections among vaccinated and convalescent individuals. Here, we demonstrate that a booster dose of UB-612 vaccine candidate delivered 7-9 months after primary vaccination increases neutralizing antibody levels by 131-, 61- and 49-fold against ancestral SARS-CoV-2, Omicron BA.1 and BA.2 variants, respectively. Based on the RBD protein binding antibody responses, we estimated a [~]95% efficacy against symptomatic COVID-19 caused by the ancestral strain after a UB-612 booster. Our results support UB-612 vaccine as a potent booster against current and emerging SARS-CoV-2 variants.

Changes in the structure of intestinal mucosal flora in colorectal cancer patients / 南方医科大学学报

OBJECTIVE@#To investigate the changes in bacterial flora in fecal samples, at the tumor loci and in adjacent mucosa in patients with colorectal cancer (CRC).@*METHODS@#We collected fecal samples from 13 patients with CRC and 20 healthy individuals and tumor and adjacent mucosa samples from 6 CRC patients. The differences in bacterial composition between the fecal and mucosa samples were analyzed with 16S rDNA sequencing and bioinformatics methods. We also detected the total number of bacteria in the feces using flow cytometry, isolated and identified the microorganisms in the fecal and mucosa samples using common bacterial culture media. We further tested the effects of 7 isolated bacterial strains on apoptosis of 3 CRC cell lines using lactate dehydrogenase detection kit.@*RESULTS@#The bacterial α-diversity in the feces of healthy individuals and in adjacent mucosa of CRC patients was significantly higher than that in the feces and tumor mucosa in CRC patients (P < 0.05). Lactobacillaceae is a specific bacteria in the feces, while Escherichia, Enterococcus, and Fusobacterium are specific bacteria in tumor mucosa of CRC patients as compared with healthy individuals. Cell experiment with3 CRC cell lines showed that Bacteroides fragilis isolated from the tumor mucosa of CRC patients produced significant inhibitory effects on cell proliferation (P < 0.0001), while the isolated strain Fusobacterium nucleatum obviously promoted the proliferation of the cell lines (P < 0.001).@*CONCLUSION@#The bacterial flora in the feces, tumor mucosa and adjacent mucosa of CRC patients is significantly different from that in the feces of healthy individuals, and the fecal flora of CRC patients can not represent the specific flora of the tumor mucosa. Inhibition of F. nucleatum colonization in the tumor mucosa and promoting B. fragilis colonization may prove beneficial for CRC treatment.

A Novel SARS-CoV-2 Multitope Protein/Peptide Vaccine Candidate is Highly Immunogenic and Prevents Lung Infection in an Adeno Associated Virus Human Angiotensin-Converting Enzyme 2 (AAV hACE2) Mouse Model

A novel multitope protein-peptide vaccine against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection and disease is described in this report. The initial development and characterization experiments are presented along with proof-of-concept studies for the vaccine candidate UB-612. UB-612 consists of eight components rationally designed for induction of potently neutralizing antibodies and broad T cell responses against SARS-CoV-2: the S1-RBD-sFc fusion protein, six synthetic peptides (one universal peptide and five SARS-CoV-2-derived peptides), a proprietary CpG TLR-9 agonist at low concentration as an excipient, and aluminum phosphate adjuvant. Through immunogenicity studies in Guinea pigs and rats, we optimized the design of protein/peptide immunogens and selected an adjuvant system, yielding a vaccine that provides excellent S1-RBD binding and high neutralizing antibody responses, robust cellular responses, and a Th1-oriented response at low doses. In challenge studies, UB- 612 vaccination reduced viral load and prevented development of disease in mouse and non-human primate challenge models. With a Phase 1 trial completed, a Phase 2 trial ongoing in Taiwan, and additional trials planned to support global authorizations, UB-612 is a highly promising and differentiated vaccine candidate for prevention of SARS-CoV-2 infection and COVID-19 disease. Author SummarySARS-CoV-2 virus, the causative agent of Coronavirus Disease 2019 (COVID-19), has spread globally since its origin in 2019, causing an unprecedented public health crisis that has resulted in greater than 4.7 million deaths worldwide. Many vaccines are under development to limit disease spread and reduce the number of cases, but additional candidates that promote a robust immune response are needed. Here, we describe a multitope protein-peptide vaccine platform that is unique among COVID-19 vaccines. The advantages of our approach are induction of both high levels of neutralizing antibodies as well as a Th/CTL response in the vaccinated host, which mimics the immune response that occurs after natural infection with SARS-CoV-2. We demonstrate that our vaccine is immunogenic and effective in preventing disease in several animal models, including AAV- hACE-2 transduced mice, and both rhesus and cynomolgus macaques. Importantly, no immunopathology was observed in the lungs of immunized animals, therefore showing that antibody-dependent enhancement (ADE) does not occur. Our study provides an additional, novel vaccine candidate for advancement in clinical trials to treat and prevent SARS-CoV-2 infection and COVID-19 disease.