InVivoMAb anti-rat Kappa Immunoglobulin Light Chain

While chemotherapy-induced tumor cell death is known to modulate the local immune landscape, its systemic impact on distant bone marrow-a site essential for immune cell maturation-remains underexplored. Here, we show that gemcitabine chemotherapy induces inflammatory caspase-1-dependent pyroptosis in epithelial cancer cells (epiCaspase-1). Despite its inflammatory nature, epiCaspase-1-mediated cell death is non-immunogenic. Clinically, elevated expression of an epiCaspase-1 gene signature correlates with worse patient outcomes. Mechanistically, epiCaspase-1 triggers the noncanonical release of IL-1α through NINJ1 lytic pores, remotely skewing bone marrow hematopoiesis towards granulocyte-monocyte progenitors and mature neutrophil output. This systemic reprogramming elevates the neutrophil-to-lymphocyte ratio (NLR) in both peripheral blood and the local tumor microenvironment. Pharmacological inhibition of caspase-1 and IL-1α disrupts this cascade, normalizes hematopoiesis, and recalibrates NLR by promoting intratumoral CD8+ T cell infiltration and activation, ultimately enhancing chemotherapeutic efficacy. These findings challenge the assumption that inflammatory pyroptosis is inherently immunogenic; instead, it can reshape systemic immune landscape towards a neutrophil-dominant inflammation in the chemotherapy context.

During the process of engulfment, phosphatidylserine is exposed on the surface of dead cells as an 'eat-me' signal and is recognized by Protein S (ProS), a secreted factor that also binds to the Mer tyrosine kinase (MerTK) on phagocytes. Despite its robust activity, this engulfment mechanism has not been exploited for therapeutic purposes. Here we develop a synthetic protein modality called Crunch (connector for removal of unwanted cell habitat) by modifying ProS, inspired by the high engulfment capability of the ProS-MerTK pathway. In Crunch, the phosphatidylserine-binding motif of ProS is replaced with a nanobody or single-chain variable fragment that recognizes the surface proteins of targeted cells. Green fluorescent protein nanobody-conjugated Crunch eliminates green fluorescent protein-expressing melanoma cells in transplantation mouse models. In addition, CD19+B cells are eliminated by anti-CD19 single-chain variable fragment-conjugated Crunch, resulting in a therapeutic effect on systemic lupus erythematosus. Both mouse and human versions of Crunch are effective, establishing this synthetic ligand as a promising tool for the elimination of targeted cells.

Neutrophils have been reported to have protective and detrimental functions in viral infections. However, the role of neutrophils remains unexplored in Japanese encephalitis virus (JEV) infection. In this study, we elucidated the dynamics of neutrophils and their influence on immune cell recruitment in subclinical and severe encephalitis in mouse models. Further, we depleted neutrophils from 3-4 week-old C57BL/6 mice using mAb1A8 (anti-Ly6G) antibody and studied their association with inflammation, viral replication, immune cell infiltration and disease outcome. We observed that an increase in JEV replication is associated with increased infiltration of neutrophils in the spleen and brain. Further studies confirmed that depletion of neutrophils at an early stage of JEV infection reduced CD8 abundance in the infected brain and accelerated death in mice. We also observed that inhibition of the CXCL12-CXCR4 signalling axis by antagonist AMD3100 reduced CD8 abundance in the brain and augmented inflammasome activation, leading to fatal encephalitis. Reduced CXCR4 levels in the spleen and blood of CD8+T cells correlated with enhanced Granzyme B level, indicating CD8 cells differentiated more into effector phenotypes in neutrophil-depleted mice. Furthermore, CD8 depletion delayed the death of mice infected with a sublethal strain compared to neutrophil-depleted mice, suggesting that neutrophils play a vital role in the early restriction of viral replication, whereas CD8 is essential later in clearing the virus. Taken together, our study sheds new light on the role of neutrophils in the pathogenic mechanisms of JEV encephalitis and highlights the importance of neutrophils and CD8 cells associated with disease outcomes.

Infection-associated thymic atrophy is common and results in T-cell imbalance and immune dysfunction. Severe dengue, caused by infection with the dengue virus (DV), is associated with perturbation of T cell functions. However, it is unclear whether perturbation of T cell functions is linked to changes in thymic function during dengue infection.