bioRxiv Science⌕ Search

bioRxiv · 10.1101/2020.06.10.144584

Multi-Dimensional Immuno-Profiling of Drosophila Hemocytes by Single Cell Mass Cytometry

Abstract

Single cell mass cytometry (SCMC) combines features of traditional flow cytometry (FACS) with mass spectrometry and allows the measurement of several parameters at the single cell level, thus permitting a complex analysis of biological regulatory mechanisms. We optimized this platform to analyze the cellular elements, the hemocytes, of the Drosophila innate immune system. We have metal-conjugated six antibodies against cell surface antigens (H2, H3, H18, L1, L4, P1), against two intracellular antigens (3A5, L2) and one anti-IgM for the detection of L6 surface antigen, as well as one anti-GFP for the detection of crystal cells in the immune induced samples. We investigated the antigen expression profile of single cells and hemocyte populations in naive, in immune induced states, in tumorous mutants (hopTum bearing a driver mutation and l(3)mbn1 carrying deficiency of a tumor suppressor) as well as in stem cell maintenance defective hdc{Delta}84 mutant larvae. Multidimensional analysis enabled the discrimination of the functionally different major hemocyte subsets, lamellocytes, plasmatocytes, crystal cell, and delineated the unique immunophenotype of the mutants. We have identified sub-populations of L2+/P1+ (l(3)mbn1), L2+/L4+/P1+ (hopTum) transitional phenotype cells in the tumorous strains and a sub-population of L4+/P1+ cells upon immune induction. Our results demonstrated for the first time, that mass cytometry, a recent single cell technology combined with multidimensional bioinformatic analysis represents a versatile and powerful tool to deeply analyze at protein level the regulation of cell mediated immunity of Drosophila.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Balog, J. A., Honti, V., Kurucz, E., Kari, B., Puskas, L. G., Ando, I., Szebeni, G. J.. 2020-06-10. Multi-Dimensional Immuno-Profiling of Drosophila Hemocytes by Single Cell Mass Cytometry. https://doi.org/10.1101/2020.06.10.144584

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

ATF3 Preserves Macrophage Cholesterol Homeostasis during Metabolic Stress

Background: Macrophages must coordinate immune activation with maintenance of cellular cholesterol homeostasis, yet the transcriptional mechanisms integrating these processes remain incompletely understood. Activating transcription factor 3 (ATF3) suppresses inflammatory and interferon responses and has been implicated in macrophage lipid metabolism, suggesting a role in coordinating immune and sterol-responsive transcriptional programs. Methods: Wild-type and ATF3-deficient bone marrow-derived macrophages were analyzed by bulk RNA sequencing following Toll-like receptor stimulation and under conditions of sterol loading or depletion. Cholesterol content, cytokine production, and sterol-responsive gene expression were quantified. Human metabolic dysfunction-associated steatotic liver disease (MASLD) datasets and Kupffer cell-specific ATF3 knockout mice were used to assess disease relevance in vivo. Results: ATF3 deficiency enhanced inflammatory and interferon-responsive transcriptional programs while suppressing a sterol-responsive gene module enriched for SREBP2 target genes. This phenotype was conserved across diverse Toll-like receptor stimuli and accompanied by persistent Ch25h upregulation. Despite exhibiting elevated cellular cholesterol, ATF3-deficient macrophages retained transcriptional responsiveness to sterol loading and depletion while demonstrating reduced induction of SREBP2-dependent genes across conditions. IFNAR blockade reduced interferon-responsive gene expression but did not normalize Ch25h or sterol-responsive gene expression. In contrast, CRISPR-mediated reduction of Ch25h partially restored sterol-responsive gene expression in inflammatory ATF3-deficient macrophages. In human MASLD, hepatic ATF3 expression positively correlated with disease severity. In mice, ATF3 was preferentially induced in Kupffer cells during metabolic stress, and Kupffer cell-specific deletion of ATF3 increased liver injury and Kupffer cell lipid accumulation. Conclusions: ATF3 supports sterol-responsive transcriptional programs while restraining inflammatory activation in macrophages. ATF3 loss results in elevated cellular cholesterol, impaired SREBP2-dependent gene expression, and persistent derepression of Ch25h, which contributes to but does not fully explain the sterol phenotype. These findings identify ATF3 as a coordinator of macrophage adaptation to inflammatory and metabolic stress and support a protective role for Kupffer cell ATF3 during metabolic liver disease.

immunology↗

Therapeutic anti-IgE antibodies generate distinct functional immune complex signatures

Therapeutic IgG anti-IgE antibodies are benchmarked by their ability to interfere with IgE-Fc[epsilon]RI binding, but their activity within IgE and IgG-containing immune complexes remains poorly defined. Here we show that omalizumab and ligelizumab form binary IgE-IgG and ternary allergen-containing immune complexes with distinct functional properties. In primary human leukocytes, these complexes exhibited antibody- and composition-dependent patterns of cellular association and activation. Using multiplexed focal molography, we resolved Fc receptor engagement across free and complexed antibody states and identified distinct receptor-binding signatures for omalizumab- and ligelizumab-containing complexes. Notably, allergen incorporation reversed the relative ability of the two antibodies to neutralize IgE-Fc[epsilon]RI interactions and remodelled Fc[gamma]R binding. Thus, immune-complex composition is a determinant of therapeutic antibody function.

immunology↗

Proliferation and mutation as humoral immune response

The affinity maturation process, through which antibodies acquire relatively high affinity for an invading pathogen, involves complex mechanisms whose relative importance is not yet fully understood. This study proposes an analytical model of this process, to investigate the main factors governing proliferation and mutation and assess their respective roles. The model suggests that the immune system should not be expected to follow a single, rigid evolutionary pattern, as a wide range of proliferation and mutation strategies can yield nearly optimal outcomes. Keywords: Antibody, antigen, affinity, B-cell, mutation, proliferation

immunology↗