Biology subjects

Novak, H.

Publications and source records attributed to Novak, H..

3 recordsLinked to original sources

bioRxiv2025

STAT3 phosphorylation in the rheumatoid arthritis immunological synapse

Targeting the JAK/STAT pathway has emerged as a key therapeutic strategy for managing Rheumatoid Arthritis (RA). JAK inhibitors suppress cytokine-mediated signaling, including the critical IL-6/STAT3 axis, thereby effectively targeting different aspects of the pathological process. However, despite their clinical efficacy, a subset of RA patients remains refractory to JAK inhibition, underscoring the need for alternative approaches. Here, we identify a novel JAK-independent mechanism of STAT3 activation, which is triggered by the formation of the immunological synapse (IS) in naive CD4+ T cells. Our data demonstrates that Lck mediates the TCR-dependent phosphorylation of STAT3 at the IS, highlighting this pathway as a previously unrecognized hallmark of early T cell activation. Furthermore, we show that the synaptic Lck/TCR-STAT3 pathway is compromised in RA. This discovery highlights a new therapeutic target for RA beyond JAK inhibitors, offering potential avenues for treating patients resistant to current therapies.

immunology↗

bioRxiv2024

Quantitating SARS-CoV-2 Neutralizing Antibodies from Human Dried Blood Spots

BackgroundIn the earliest days of COVID-19 pandemic, the collection of dried blood spots (DBS) enabled public health laboratories to undertake population-scale seroprevalence studies to estimate rates of SARS-CoV-2 exposure. With SARS-CoV-2 seropositivity levels now estimated to exceed 94% in the United States, attention has turned to using DBS to assess functional (neutralizing) antibodies within cohorts of interest. MethodsContrived DBS eluates from convalescent, fully vaccinated and pre-COVID-19 serum samples were evaluated in SARS-CoV-2 plaque reduction neutralization titer (PRNT) assays, a SARS-CoV-2 specific 8-plex microsphere immunoassay, a cell-based pseudovirus assay, and two different spike-ACE2 inhibition assays, an in-house Luminex-based RBD-ACE2 inhibition assay and a commercial real-time PCR-based inhibition assay (NAB-Sure). ResultsDBS eluates from convalescent individuals were compatible with the spike-ACE2 inhibition assays, but not cell-based pseudovirus assays or PRNT. However, the insensitivity of cell-based pseudovirus assays was overcome with DBS eluates from vaccinated individuals with high SARS-CoV-2 antibody titers. ConclusionSARS-CoV-2 neutralizing titers can be derived with confidence from DBS eluates, thereby opening the door to the use of these biospecimens for the analysis of vulnerable populations and normally hard to reach communities.

immunology↗

bioRxiv2021

Durable Immunity to Ricin Toxin Elicited by a Thermostable, Lyophilized Subunit Vaccine

The development of vaccines against biothreat toxins like ricin (RT) is considered an integral component of the United States national security efforts. RiVax(R) is a thermostable, lyophilized RT subunit vaccine adsorbed to aluminum salt adjuvant intended for use by military personnel and first responders. Phase 1 studies indicated that RiVax is safe and immunogenic, while a three dose, intramuscular vaccination regimen in non-human primates elicited protection against lethal dose RT challenge by aerosol. Here we investigated, in a mouse model, the durability of RiVax-induced antibody responses and corresponding immunity to lethal dose RT challenge. Groups of mice were subcutaneously administered 3 or 1 g of RiVax on days 0 and 21 and challenged with 10 x LD50 RT by injection at six different intervals over the course of twelve months. Serum antibody titers and epitope-specific competition assays were determined prior to each challenge. We report that the two-dose, 3 g regimen conferred near complete protection against RT challenge on day 35 and complete protection thereafter (challenge days 65, 95, 125, 245, and 365). The two-dose, 3 g regimen was superior to the 1 g regimen as revealed by slight differences in survival and morbidity scores (e.g., hypoglycemia, weight loss) on challenge days 35 and 365. In separate experiments, a single 3 g RiVax vaccination proved only marginally effective at eliciting protective immunity to RT, underscoring the necessity of a prime-boost regimen to achieve full and long-lasting protection against RT. IMPORTANCERicin toxin (RT) is a notorious biothreat, as exposure to even trace amounts via injection or inhalation can induce organ failure and death within a matter of hours. In this study, we advance the preclinical testing of a candidate RT vaccine known as RiVax(R). RiVax is a recombinant non-toxic derivative of RTs enzymatic subunit that has been evaluated for safety in Phase I clinical trials and efficacy in a variety of animal models. We demonstrate that two doses of RiVax is sufficient to protect mice from lethal dose RT challenge for up to one year. We describe kinetics and other immune parameters of the antibody response to RiVax and discuss how these immune factors may translate to humans.

immunology↗