Biology subjects

Luning Prak, E. T.

Publications and source records attributed to Luning Prak, E. T..

4 recordsLinked to original sources

bioRxiv2022

STAT3 signaling in B cells controls germinal center zone organization and recycling

Germinal centers (GCs), sites of antibody affinity maturation, are organized into dark (DZ) and light (LZ) zones. Here, we uncovered a B cell intrinsic role for STAT3 in GC DZ and LZ organization. Altered zonal organization of STAT3-deficient GCs dampened GC output of long-lived plasma cells (LL-PCs) but increased memory B cells (MBCs). Tfh-GC B cell interaction drive STAT3 tyrosine 705 and serine 727 phosphorylation in LZ B cells, facilitating their recycling into the DZ. An inducible system confirmed STAT3 is not involved in initiating or maintaining the GC but sustains GC zonal organization by regulating GC B cell recycling. RNAseq and ChIPseq analysis identified genes regulated by STAT3 that are critical for LZ cell recycling and transiting through the DZ proliferation and differentiation phases of the DZ. Thus, STAT3 signaling in B cells controls GC zone organization and recycling, and GC egress of LL-PCs, but negatively regulates MBC output. SummaryFike et al. describe a previously unrecognized mechanism by which B cell intrinsic STAT3 signaling controls the germinal center (GC) dark and light zone organization, GC B cell recycling, and GC output of long-lived plasma cells but negatively regulates memory B cells.

immunology↗

bioRxiv2021

Sex-specific differences in the function and differentiation of ABCsmark TLR7-driven immunopathogenesis

Sex differences characterize immune responses to viruses and autoimmune diseases like SLE. ABCs are an emerging population of CD11c+ T-bet+ B cells critical for antiviral responses and autoimmune disorders. DEF6 and SWAP70, are two homologous molecules whose combined absence in double-knock-out mice (DKOs) leads to a lupus syndrome in females marked by an accumulation of ABCs. Here we demonstrate that DKO ABCs exhibit sex-specific differences in their expansion, upregulation of an ISG signature, and further differentiation. BCR sequencing and fate mapping experiments reveal that DKO ABCs undergo oligoclonal expansion and differentiate into both CD11c+ and CD11c- effector populations with pathogenic and proinflammatory potential. Tlr7 duplication in DKO males overrides the sex-bias and further augments the dissemination and pathogenicity of ABCs resulting in severe pulmonary inflammation and early mortality. Thus, sexual dimorphism shapes the expansion, function, and differentiation of ABCs contributing to the sex-bias that accompanies TLR7-driven immunopathogenesis.

immunology↗

bioRxiv2020

Immunologic perturbations in severe COVID-19/SARS-CoV-2 infection

Although critical illness has been associated with SARS-CoV-2-induced hyperinflammation, the immune correlates of severe COVID-19 remain unclear. Here, we comprehensively analyzed peripheral blood immune perturbations in 42 SARS-CoV-2 infected and recovered individuals. We identified broad changes in neutrophils, NK cells, and monocytes during severe COVID-19, suggesting excessive mobilization of innate lineages. We found marked activation within T and B cells, highly oligoclonal B cell populations, profound plasmablast expansion, and SARS-CoV-2-specific antibodies in many, but not all, severe COVID-19 cases. Despite this heterogeneity, we found selective clustering of severe COVID-19 cases through unbiased analysis of the aggregated immunological phenotypes. Our findings demonstrate broad immune perturbations spanning both innate and adaptive leukocytes that distinguish dysregulated host responses in severe SARS-CoV-2 infection and warrant therapeutic investigation. One Sentence SummaryBroad immune perturbations in severe COVID-19

immunology↗

bioRxiv2019

Chronic viral infection promotes early germinal center exit of B cells and impaired antibody development.

Chronic viral infections disrupt B cell responses leading to impaired affinity maturation and delayed control of viremia. Previous studies have identified early pre-germinal center (GC) B cell attrition but the impact of chronic infections on B cell fate decisions in the GC remains poorly understood. To address this question, we used single-cell transcriptional profiling of virus-specific GC B cells to test the hypothesis that chronic viral infection disrupted GC B cell fate decisions leading to suboptimal humoral immunity. These studies revealed a critical GC differentiation checkpoint that is disrupted by chronic infection, specifically at the point of dark zone re-entry. During chronic viral infection, virus-specific GC B cells were shunted towards terminal plasma cell (PC) or memory B cell (MBC) fates at the expense of continued participation in the GC. Early GC exit was associated with decreased B cell mutational burden and antibody quality. Persisting antigen and inflammation independently drove facets of dysregulation, with a key role for inflammation in directing premature terminal GC B cell differentiation and GC exit. Thus, these studies define GC defects during chronic viral infection and identify a critical GC checkpoint that is short-circuited, preventing optimal maturation of humoral immunity.

immunology↗