Microbiota-induced plastic T cells enhance immune control of antigen-sharing tumors.

Therapies that harness the immune system to target and eliminate tumor cells have revolutionized cancer care. Immune checkpoint blockade (ICB), which boosts the anti-tumor immune response by inhibiting negative regulators of T cell activation, is remarkably successful in a subset of cancer patients, yet a significant proportion do not respond to treatment, emphasizing the need to understand factors influencing the therapeutic efficacy of ICB. The gut microbiota, consisting of trillions of microorganisms residing in the gastrointestinal tract, has emerged as a critical determinant of immune function and response to cancer immunotherapy, with multiple studies demonstrating association of microbiota composition with clinical response.

A RORγt cell instructs gut microbiota-specific T cell differentiation.

The mutualistic relationship of gut-resident microbiota and the host immune system promotes homeostasis that ensures maintenance of the microbial community and of a largely non-aggressive immune cell compartment. The consequences of disturbing this balance include proximal inflammatory conditions, such as Crohn's disease, and systemic illnesses. This equilibrium is achieved in part through the induction of both effector and suppressor arms of the adaptive immune system.

Serum Amyloid A Proteins Induce Pathogenic Th17 Cells and Promote Inflammatory Disease.

Lymphoid cells that produce interleukin (IL)-17 cytokines protect barrier tissues from pathogenic microbes but are also prominent effectors of inflammation and autoimmune disease. T helper 17 (Th17) cells, defined by RORγt-dependent production of IL-17A and IL-17F, exert homeostatic functions in the gut upon microbiota-directed differentiation from naive CD4 T cells. In the non-pathogenic setting, their cytokine production is regulated by serum amyloid A proteins (SAA1 and SAA2) secreted by adjacent intestinal epithelial cells.

The histone chaperone CAF-1 cooperates with the DNA methyltransferases to maintain silencing in cytotoxic T cells.

The transcriptional repression of alternative lineage genes is critical for cell fate commitment. Mechanisms by which locus-specific gene silencing is initiated and heritably maintained during cell division are not clearly understood. To study the maintenance of silent gene states, we investigated how the gene is stably repressed in CD8 T cells.

Isolation of an in Vitro Affinity-Matured, Thermostable "Headless" HA Stem Fragment That Binds Broadly Neutralizing Antibodies with High Affinity.

The surface glycoprotein hemagglutinin (HA) of influenza virus is the primary target for the design of an effective universal influenza vaccine as it is capable of eliciting broadly cross-reactive antibodies against different HA subtypes. Several monoclonal antibodies targeting the stem region of HA that are able to neutralize various subtypes of influenza virus have been isolated in the recent past. Designing a stable, HA stem immunogen that attains a native-like conformation and can elicit such antibodies has been a challenge.

Rapid Mapping of Protein Binding Sites and Conformational Epitopes by Coupling Yeast Surface Display to Chemical Labeling and Deep Sequencing.

Delineating the precise regions on an antigen that are targeted by antibodies is important for the development of vaccines and antibody therapeutics. X-ray crystallography and NMR are considered the gold standard for providing precise information about these binding sites at atomic resolution. However, these are labor-intensive and require purified protein at high concentration.

Mapping Protein Binding Sites and Conformational Epitopes Using Cysteine Labeling and Yeast Surface Display.

We describe a facile method for mapping protein:ligand binding sites and conformational epitopes. The method uses a combination of Cys scanning mutagenesis, chemical labeling, and yeast surface display. While Ala scanning is widely used for similar purposes, often mutation to Ala (or other amino acids) has little effect on binding, except at hotspot residues.

Design of Escherichia coli-expressed stalk domain immunogens of H1N1 hemagglutinin that protect mice from lethal challenge.

The hemagglutinin protein (HA) on the surface of influenza virus is essential for viral entry into the host cells. The HA1 subunit of HA is also the primary target for neutralizing antibodies. The HA2 subunit is less exposed on the virion surface and more conserved than HA1.

Design of an HA2-based Escherichia coli expressed influenza immunogen that protects mice from pathogenic challenge.

Influenza HA is the primary target of neutralizing antibodies during infection, and its sequence undergoes genetic drift and shift in response to immune pressure. The receptor binding HA1 subunit of HA shows much higher sequence variability relative to the metastable, fusion-active HA2 subunit, presumably because neutralizing antibodies are primarily targeted against the former in natural infection. We have designed an HA2-based immunogen using a protein minimization approach that incorporates designed mutations to destabilize the low pH conformation of HA2.