Suppression of de novo antibody responses against SARS-CoV2 and the Omicron variant after mRNA vaccination and booster in patients with B cell malignancies undergoing active treatment, but maintenance of pre-existing antibody levels against endemic viruses.

The impact of SARS-CoV2 vaccination in cancer patients remains incompletely understood given the heterogeneity of cancer and cancer therapies. We assessed vaccine-induced antibody response to the SARS-CoV2 Omicron (B.1.1.529) variant in 57 patients with B cell malignancies with and without active B cell-targeted therapy. Ancestral- and Omicron-reactive antibody levels were determined by ELISA and neutralization assays. In over one third of vaccinated patients at the pre-booster timepoint, there were no ELISA-detectable antibodies against either the ancestral strain or Omicron variant. The lack of vaccine-induced antibodies was predominantly in patients receiving active therapy such as anti-CD20 monoclonal antibody (mAb) or Brutons tyrosine kinase inhibitors (BTKi). While booster immunization was able to induce detectable antibodies in a small fraction of seronegative patients, the benefit was disproportionately evident in patients not on active therapy. Importantly, in patients with post-booster ELISA-detectable antibodies, there was a positive correlation of antibody levels against the ancestral strain and Omicron variant. Booster immunization increased overall antibody levels, including neutralizing antibody titers against the ancestral strain and Omicron variant; however, predominantly in patients without active therapy. Furthermore, ancestral strain neutralizing antibody titers were about 5-fold higher in comparison with those to Omicron, suggesting that even with booster administration, there may be reduced protection against the Omicron variant. Interestingly, in almost all patients regardless of active therapy, including those unable to generate detectable antibodies against SARS-CoV2 spike, we observed comparable levels of EBV, influenza, and common cold coronavirus reactive antibodies demonstrating that B cell-targeting therapies primarily impair de novo but not pre-existing antibody levels. These findings suggest that patients with B cell malignancies on active therapy may be at disproportionately higher risk to new versus endemic viral infection and suggest utility for vaccination prior to B cell-targeted therapy.

mRNA Booster Vaccines Elicit Strong Protection Against SARS-CoV-2 Omicron Variant in Cancer Patients

Following its emergence in late November of 2020, the SARS-CoV-2 Omicron (B.1.1.529) variant has caused major global public health concerns. We recently demonstrated that in healthy adults the Omicron variant exhibits strong resistance to immunity induced by two doses of the mRNA vaccines, but a booster mRNA vaccine dose can provide strong protection against Omicron. However, it is currently unknown how well these mRNA vaccine boosters protect immunocompromised groups, including cancer patients, from the Omicron variant. Here we show that (1) neutralizing antibody (nAb) titers against the Delta and Omicron variants in cancer patients after two-dose mRNA vaccines are 4.2-fold and 21.3-fold lower, respectively, compared to the ancestral D614G, and (2) nAb titers against the Delta and Omicron variants in boosted cancer patients are 3.6-fold and 5.1-fold lower, respectively, compared to D614G. Our findings highlight the effectiveness and need for booster vaccination strategies in immunocompromised groups including cancer patients to protect from the Omicron variant.

Immunological Insights Into the Therapeutic Roles of CD24Fc Against Severe COVID-19

BACKGROUNDSARS-CoV-2 causes COVID-19 through direct lysis of infected lung epithelial cells, which releases damage-associated molecular patterns (DAMPs) and induces a pro-inflammatory cytokine milieu causing systemic inflammation. Anti-viral and anti-inflammatory agents have shown limited therapeutic efficacy. Soluble CD24 (CD24Fc) is able to blunt the broad inflammatory response induced by DAMPs in multiple models. A recent randomized phase III trial evaluating the impact of CD24Fc in patients with severe COVID-19 demonstrated encouraging clinical efficacy. METHODSWe studied peripheral blood samples obtained from patients enrolled at a single institution in the SAC-COVID trial (NCT04317040) collected before and after treatment with CD24Fc or placebo. We performed high dimensional spectral flow cytometry analysis of peripheral blood mononuclear cells and measured the levels of a broad array of cytokines and chemokines. A systems analytical approach was used to discern the impact of CD24Fc treatment on immune homeostasis in patients with COVID-19. FINDINGSTwenty-two patients were enrolled, and the clinical characteristics from the CD24Fc vs. placebo groups were matched. Using high-content spectral flow cytometry and network-level analysis, we found systemic hyper-activation of multiple cellular compartments in the placebo group, including CD8+ T cells, CD4+ T cells, and CD56+ NK cells. By contrast, CD24Fc-treated patients demonstrated blunted systemic inflammation, with a return to homeostasis in both NK and T cells within days without compromising the ability of patients to mount an effective anti-Spike protein antibody response. A single dose of CD24Fc significantly attenuated induction of the systemic cytokine response, including expression of IL-10 and IL-15, and diminished the coexpression and network connectivity among extensive circulating inflammatory cytokines, the parameters associated with COVID-19 disease severity. INTERPRETATIONOur data demonstrates that CD24Fc treatment rapidly down-modulates systemic inflammation and restores immune homeostasis in SARS-CoV-2-infected individuals, supporting further development of CD24Fc as a novel therapeutic against severe COVID-19. FUNDINGNIH

Sulfuretin Prevents Obesity and Metabolic Diseases in Diet Induced Obese Mice

The global obesity epidemic and associated metabolic diseases require alternative biological targets for new therapeutic strategies. In this study, we show that a phytochemical sulfuretin suppressed adipocyte differentiation of preadipocytes and administration of sulfuretin to high fat diet-fed obese mice prevented obesity and increased insulin sensitivity. These effects were associated with a suppressed expression of inflammatory markers, induced expression of adiponectin, and increased levels of phosphorylated ERK and AKT. To elucidate the molecular mechanism of sulfuretin in adipocytes, we performed microarray analysis and identified activating transcription factor 3 (Atf3) as a sulfuretin-responsive gene. Sulfuretin elevated Atf3 mRNA and protein levels in white adipose tissue and adipocytes. Consistently, deficiency of Atf3 promoted lipid accumulation and the expression of adipocyte markers. Sulfuretin’s but not resveratrol’s anti-adipogenic effects were diminished in Atf3 deficient cells, indicating that Atf3 is an essential factor in the effects of sulfuretin. These results highlight the usefulness of sulfuretin as a new anti-obesity intervention for the prevention of obesity and its associated metabolic diseases.

Induction of thermogenic adipocytes: molecular targets and thermogenic small molecules

Adipose tissue is a central metabolic organ that controls energy homeostasis of the whole body. White adipose tissue (WAT) stores excess energy in the form of triglycerides, whereas brown adipose tissue (BAT) dissipates energy in the form of heat through mitochondrial uncoupling protein 1 (Ucp1). A newly identified adipose tissue called ‘beige fat’ (BAT-like) is produced through a process called WAT browning. This tissue mainly resides in WAT depots and displays intermediate characteristics of both WAT and BAT. Since the recent discovery of BAT in the human body, along with the identification of molecular targets for BAT activation, stimulating energy expenditure has been considered as a great strategy to treat human obesity and metabolic diseases. Here we summarize recent findings regarding molecular targets and thermogenic small molecules that can stimulate BAT and increase energy expenditure, with an emphasis on possible therapeutic applications in humans.