Wei Luo

Viral infections induce heterogeneous memory T and B cell populations that may rapidly recall and provide protection against re-infection. The immunomodulatory cytokine interleukin-10 (IL-10) is well described for its role in restricting immunopathology during viral infection; however, less is known about its role in the development of cellular and humoral immune memory. In this review, we explore the current knowledge of the role of IL-10 in the regulation of antiviral memory T and B cell development. Furthermore, we highlight the importance of the cellular source and timing of IL-10 production in regulating this complex process.

Personalized cancer vaccines represent a revolutionary frontier in oncology, harnessing the unique genetic and molecular profile of individual tumors to elicit targeted immune responses. This review provides a comprehensive overview of the current landscape and future perspectives of neoantigen-based personalized cancer vaccines, encompassing peptide, mRNA, DNA, autologous dendritic cell, and viral or bacterial vector platforms. We further discuss the integration of immune adjuvants, delivery systems, and combinational strategies, particularly with immune checkpoint inhibitions, to overcome tumor-induced immune exhaustion and improve therapeutic efficacy. Despite significant clinical progress over the past decade in this space, major challenges remain in immunogenic neoantigens prediction, streamlining individualized vaccine manufacturing, and optimization of combinational regimens to maximize durable antitumor responses. By reviewing recent preclinical and clinical studies on neoantigen-based cancer vaccines, this review highlights key advances, identifies persistent translational bottlenecks, and underscores the need for biomarker-guided mechanistically informed trials to fully unleash the clinical potential of neoantigen-based personalized cancer vaccines in the era of precision immuno-oncology.

Current SARS‐CoV‐2 vaccines primarily elicit antibodies targeting the variable receptor‐binding domain in the S1 subunit of the spike protein, resulting in limited cross‐reactivity and short‐lived immunity against emerging variants. The conserved S2 subunit presents a promising vaccine target for broad and durable protection, but the immunodominance in vaccine‐induced germinal center (GC) responses hinders effective antibody generation against S2. Here, a polymeric toll‐like receptor 7 agonist nanoparticle (TLR7‐NP) adjuvant is reported, well designed to enhance lymph node targeting and more efficiently activate S2‐specific B cells. When combined with Alum‐adsorbed SARS‐CoV‐2 HexaPro spike protein, TLR7‐NP promotes early GC recruitment of S2‐specific B cells and overcomes the immunodominance, leading to early and robust S2‐specific antibody responses. Compared to conventional TLR7‐Alum adjuvanted subunit vaccine and clinically used SARS‐CoV‐2 mRNA vaccine, TLR7‐NP adjuvant induces stronger humoral immune responses across sarbecoviruses and betacoronaviruses and promotes long‐lived plasma cell and memory B cell formation. These findings present a direct B cell‐activating adjuvant approach for effective pan‐coronavirus vaccine development.

The germinal center (GC) reaction is essential for generating high-quality humoral memory. Positively selected GC B cells must decide whether to remain in the GC for further affinity maturation or differentiate into memory or plasma cells (PCs). Previously, we identified IL-21R and CD40 signaling as critical promoters of GC B cell effector differentiation. However, the mechanisms regulating the strength of these signals remain unclear. PTEN, a negative regulator of PI3K signaling, is markedly upregulated in GC B cells. To explore the role of PTEN in GC B cell fate decisions, we used a tamoxifen-driven Cre system to delete PTEN in B cells after GC reaction was fully established. We found that PTEN deletion in ongoing GC B cells led to significantly increased differentiation into PCs, while having limited effects on class switching or memory precursor differentiation. These results were further confirmed using a GC B cell transfer system, where wild-type and PTEN-deficient GC B cells were transferred into the same recipient mice. Mechanistically, PTEN deletion or inhibition in established GC B cells resulted in more sustained IL-21R signaling and enhanced CD40 signaling—both known to promote PC differentiation. Interestingly, Peyer’s patch GC B cells exhibited higher PTEN levels than de novo GC B cells generated through immunization. Notably, PTEN deficiency selectively expanded GC B cells in Peyer’s patches but had no impact on those induced by immunization. These findings reveal previously unrecognized roles for PTEN in regulating GC B cell signaling and limiting their differentiation into PCs.

Background: The sterol regulatory element‐binding protein (SREBP) pathway is essential for maintaining sterol homeostasis during B cell activation and germinal center B cell proliferation. However, its potential as a therapeutic target to treat B‐cell lymphoma remains unclear. Methods: We examined SREBP protein expression in human B‐cell lymphoma samples using immunohistochemistry. Additionally, we conducted in vitro studies using SREBP signaling inhibitors in combination with rapamycin to assess their effects on cell proliferation and lipid metabolism in B‐cell lymphoma cells. Results: Our analysis revealed high levels of SREBP2 protein expression in human B‐cell lymphoma samples. Inhibiting SREBP signaling or its downstream target HMG‐CoA reductase (HMGCR) with Fatostatin or Simvastatin effectively suppressed B‐cell lymphoma cell proliferation. However, B‐cell lymphoma cells responded to statin treatment by activating the mTORC1‐pS6 pathway, suggesting a compensatory mechanism to overcome statin‐induced cell cycle arrest. Combining low‐dose statin treatment with the mTOR inhibitor rapamycin produced a synergistic effect, significantly inhibiting B‐cell lymphoma proliferation, cell cycle progression, and lipid raft formation. Conclusions: These results highlight the potential of a combined therapeutic approach targeting both SREBP and mTORC1 as a novel strategy for treating B‐cell lymphoma.

T follicular regulatory (TFR) cells are found in the germinal center (GC) response and, along with T follicular helper (TFH) cells, help to control the development of high-affinity antibodies (Ab). Although TFR cells are generally thought to repress GC B cells and the Ab response, we have previously shown that in a mouse food allergy model, TFR cells produce IL-10 and play an essential helper role such that in the absence of TFR cells, IgE responses are diminished. Here we show that in this food allergy response, TFR cells produced IL-4 that promotes the generation of antigen-specific IgE. We show that food allergy–primed TFR cells specifically upregulate IL-4 gene transcription and produce functional IL-4 that promoted IgE responses both in vitro and in vivo. We determined that IgE responses are dependent on a high level of IL-4 produced by follicular T cells in the GC, explaining the need for IL-4 produced by TFR cells in the food allergy response. Overall, our findings have demonstrated that in food allergy, TFR cells can produce IL-4 and regulate IgE in a manner that augments the role of TFH cells in IgE responses.

Dendritic cells (DCs) are specialized sentinel and APCs coordinating innate and adaptive immunity. Through proteins on their cell surface, DCs sense changes in the environment, internalize pathogens, present processed Ags, and communicate with other immune cells. By combining chemical labeling and quantitative mass spectrometry, we systematically profiled and compared the cell-surface proteomes of human primary conventional DCs (cDCs) in their resting and activated states. TLR activation by a lipopeptide globally reshaped the cell-surface proteome of cDCs, with >100 proteins upregulated or downregulated. By simultaneously elevating positive regulators and reducing inhibitory signals across multiple protein families, the remodeling creates a cell-surface milieu promoting immune responses. Still, cDCs maintain the stimulatory-to-inhibitory balance by leveraging a distinct set of inhibitory molecules. This analysis thus uncovers the molecular complexity and plasticity of the cDC cell surface and provides a roadmap for understanding cDC activation and signaling.

Both B cell receptor (BCR) and CD40 signaling are rewired in germinal center (GC) B cells (GCBCs) to synergistically induce c-MYC and phosphorylated S6 ribosomal protein (p-S6), markers of positive selection. How interleukin-21 (IL-21), a key T follicular helper (T _FH )–derived cytokine, affects GCBCs is unclear. Like BCR and CD40 signals, IL-21 receptor (IL-21R) plus CD40 signals also synergize to induce c-MYC and p-S6 in GCBCs. However, IL-21R plus CD40 stimulation differentially affects GCBC fate compared with BCR plus CD40 ligation—engaging unique molecular mechanisms—as revealed by bulk RNA sequencing (RNA-seq), single-cell RNA-seq, and flow cytometry of GCBCs in vitro and in vivo. Whereas both signal pairs induced BLIMP1 in some GCBCs, only the IL-21R/CD40 combination induced IRF4 ^hi /CD138 ⁺ cells, indicative of plasma cell differentiation, along with CCR6 ⁺ /CD38 ⁺ memory B cell precursors. These findings reveal a second positive selection pathway in GCBCs, document rewired IL-21R signaling in GCBCs, and link specific T _FH - and Ag-derived signals to GCBC differentiation.