Heterogeneity of lipopolysaccharide counteracts macrophage and antimicrobial peptide defenses.

S is comprised of over 2,500 serovars, in which non-typhoidal serovars (NTS), Enteritidis (SE), and Typhimurium (STM) are the most clinically associated with human infections. Although NTS have similar genetic elements to cause disease, phenotypic variation including differences in lipopolysaccharide (LPS) composition may control immune evasion. Here, we demonstrate that macrophage host defenses and LL-37 antimicrobial efficacy against SE and STM are substantially altered by LPS heterogeneity.

Comparative single-cell transcriptomic profile of hybrid immunity induced by adenovirus vector-based COVID-19 vaccines.

In this study, antibody response and a single-cell RNA-seq analysis were conducted on peripheral blood mononuclear cells from five different groups: naïve subjects vaccinated with AZD1222 (AZ) or Ad5-nCoV (Cso), individuals previously infected and later vaccinated (hybrid) with AZD1222 (AZ-hb) or Ad5-nCoV (Cso-hb), and those who were infected and had recovered from COVID-19 (Inf). The results showed that AZ induced more robust neutralizing antibody responses than Cso. The single-cell RNA data revealed a high frequency of memory B cells in the Cso and Cso-hb.

Design, structure and plasma binding of ancestral β-CoV scaffold antigens.

We report the application of ancestral sequence reconstruction on coronavirus spike protein, resulting in stable and highly soluble ancestral scaffold antigens (AnSAs). The AnSAs interact with plasma of patients recovered from COVID-19 but do not bind to the human angiotensin-converting enzyme 2 (ACE2) receptor. Cryo-EM analysis of the AnSAs yield high resolution structures (2.

Vaccination with attachment proteins protects against gastric cancer.

Most cases of gastric cancer are caused by chronic infection, but the lack of early onco-diagnostics and a high risk for antibiotic resistance hampers early intervention through eradication of infection by antibiotics. We reported on a protective mechanism where gastric mucosal attachment can be reduced by natural antibodies that block the binding of its attachment protein BabA. Here we show that challenge infection with induced response of such blocking antibodies in both human volunteers and in rhesus macaques, that mucosal vaccination with BabA protein antigen induced blocking antibodies in rhesus macaques, and that vaccination in a mouse model induced blocking antibodies that reduced gastric mucosal inflammation, preserved the gastric juice acidity, and fully protected the mice from gastric cancer caused by .

attachment-blocking antibodies protect against duodenal ulcer disease.

The majority of the world population carry the gastric pathogen . Fortunately, most individuals experience only low-grade or no symptoms, but in many cases the chronic inflammatory infection develops into severe gastric disease, including duodenal ulcer disease and gastric cancer. Here we report on a protective mechanism where attachment and accompanying chronic mucosal inflammation can be reduced by antibodies that are present in a vast majority of carriers.

19n01, a broadly neutralizing antibody against omicron BA.1, BA.2, BA.4/5, and other SARS-CoV-2 variants of concern.

This study reports the isolation and characterization of a human monoclonal antibody (mAb) called 19n01. This mAb was isolated by using single-cell RNAseq of B cells from donors infected with the ancestral strain. This mAb possesses a potent and broad capacity to bind and neutralize all previously circulating variants of concern (VOCs), including Omicron sublineages BA.

Evaluation of Alternative Colony Hybridization Methods for Pathogenic Vibrios.

Vibrios, such as , are naturally occurring halophilic bacteria that are a major cause of foodborne illness. Because of their autochthonous nature, managing vibrio levels in marine and estuarine environments is impossible. Instead, it is crucial to reliably enumerate their abundance to minimize human exposure.

Human neutralizing antibodies to cold linear epitopes and subdomain 1 of the SARS-CoV-2 spike glycoprotein.

Emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants diminishes the efficacy of vaccines and antiviral monoclonal antibodies. Continued development of immunotherapies and vaccine immunogens resilient to viral evolution is therefore necessary. Using coldspot-guided antibody discovery, a screening approach that focuses on portions of the virus spike glycoprotein that are both functionally relevant and averse to change, we identified human neutralizing antibodies to highly conserved viral epitopes.

Lactobacilli as a Vector for Delivery of Nanobodies against Norovirus Infection.

Passive administration of neutralizing antibodies (Abs) is an attractive strategy for the control of gastrointestinal infections. However, an unanswered practical concern is the need to assure the stability of sufficient amounts of orally administered neutralizing Abs against intestinal pathogens (e.g.

Human neutralizing antibodies to cold linear epitopes and to subdomain 1 of SARS-CoV-2.

Unlabelled: Emergence of SARS-CoV-2 variants diminishes the efficacy of vaccines and antiviral monoclonal antibodies. Continued development of immunotherapies and vaccine immunogens resilient to viral evolution is therefore necessary. Using coldspot-guided antibody discovery, a screening approach that focuses on portions of the virus spike that are both functionally relevant and averse to change, we identified human neutralizing antibodies to highly conserved viral epitopes.

Genetic and immunologic evaluation of children with inborn errors of immunity and severe or critical COVID-19.

Background: Most severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected individuals are asymptomatic or only exhibit mild disease. In about 10% of cases, the infection leads to hypoxemic pneumonia, although it is much more rare in children.

Objective: We evaluated 31 young patients aged 0.

Heterologous immunization with inactivated vaccine followed by mRNA-booster elicits strong immunity against SARS-CoV-2 Omicron variant.

The recent emergence of the Omicron variant has raised concerns on vaccine efficacy and the urgent need to study more efficient vaccination strategies. Here we observed that an mRNA vaccine booster in individuals vaccinated with two doses of inactivated vaccine significantly increased the plasma level of specific antibodies that bind to the receptor-binding domain (RBD) or the spike (S) ectodomain (S1 + S2) of both the G614 and the Omicron variants, compared to two doses of homologous inactivated vaccine. The level of RBD- and S-specific IgG antibodies and virus neutralization titers against variants of concern in the heterologous vaccination group were similar to that in individuals receiving three doses of homologous mRNA-vaccine or a boost of mRNA vaccine after infection, but markedly higher than that in individuals receiving three doses of a homologous inactivated vaccine.

Human serum from SARS-CoV-2-vaccinated and COVID-19 patients shows reduced binding to the RBD of SARS-CoV-2 Omicron variant.

Background: The COVID-19 pandemic is caused by the betacoronavirus SARS-CoV-2. In November 2021, the Omicron variant was discovered and immediately classified as a variant of concern (VOC), since it shows substantially more mutations in the spike protein than any previous variant, especially in the receptor-binding domain (RBD). We analyzed the binding of the Omicron RBD to the human angiotensin-converting enzyme-2 receptor (ACE2) and the ability of human sera from COVID-19 patients or vaccinees in comparison to Wuhan, Beta, or Delta RBD variants.

Inherited IFNAR1 Deficiency in a Child with Both Critical COVID-19 Pneumonia and Multisystem Inflammatory Syndrome.

Background: Inborn errors of immunity (IEI) and autoantibodies to type I interferons (IFNs) underlie critical COVID-19 pneumonia in at least 15% of the patients, while the causes of multisystem inflammatory syndrome in children (MIS-C) remain elusive.

Objectives: To detect causal genetic variants in very rare cases with concomitant critical COVID-19 pneumonia and MIS-C.

Methods: Whole exome sequencing was performed, and the impact of candidate gene variants was investigated.

Immunity to SARS-CoV-2 up to 15 months after infection.

Information concerning the longevity of immunity to SARS-CoV-2 following natural infection may have considerable implications for durability of immunity induced by vaccines. Here, we monitored the SARS-CoV-2 specific immune response in COVID-19 patients followed up to 15 months after symptoms onset. Following a peak at day 15-28 postinfection, the IgG antibody response and plasma neutralizing titers gradually decreased over time but stabilized after 6 months.

SARS-CoV-2-specific B- and T-cell immunity in a population-based study of young Swedish adults.

Background: Young adults are now considered major spreaders of coronavirus disease 2019 (COVID-19) disease. Although most young individuals experience mild to moderate disease, there are concerns of long-term adverse health effects. The impact of COVID-19 disease and to which extent population-level immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exists in young adults remain unclear.

X-Linked TLR7 Deficiency Underlies Critical COVID-19 Pneumonia in a Male Patient with Ataxia-Telangiectasia.

Background: Coronavirus disease 2019 (COVID-19) exhibits a wide spectrum of clinical manifestations, ranging from asymptomatic to critical conditions. Understanding the mechanism underlying life-threatening COVID-19 is instrumental for disease prevention and treatment in individuals with a high risk.

Objectives: We aimed to identify the genetic cause for critical COVID-19 pneumonia in a patient with a preexisting inborn error of immunity (IEI).

Antibody therapy for COVID-19.

Purpose Of Review: To provide an update of the current state of antibody therapy for Severe Acute Respiratory Syndrome Coronavirus 2 infection that has progressed immensely in a very short time period.

Recent Findings: Limited clinical effect of classical passive immunotherapy (plasma therapy, hyperimmune immunoglobulin [IgG] preparations) whereas monoclonal antibody therapy, if initiated early in the disease process, shows promising results.

Summary: Although antibody therapy still remains to be fully explored in patients with COVID-19, a combination of IgG monoclonal antibodies against the receptor-binding domain of the spike protein currently appears to provide the best form of antibody therapy, Immunoglobulin A dimers and Immunoglobulin M pentamers also show promising preliminary therapeutic results.

Persistence of SARS-CoV-2-specific B and T cell responses in convalescent COVID-19 patients 6-8 months after the infection.

Background: Monitoring the adaptive immune responses during the natural course of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection provides useful information for the development of vaccination strategies against this virus and its emerging variants. We thus profiled the serum anti-SARS-CoV-2 antibody (Ab) levels and specific memory B and T cell responses in convalescent coronavirus disease 2019 (COVID-19) patients.

Methods: A total of 119 samples from 88 convalescent donors who experienced mild to critical disease were tested for the presence of elevated anti-spike and anti-receptor binding domain Ab levels over a period of 8 months.