Ex vivo immune profiling in patient blood enables quantification of innate immune effector functions

AbstractThe assessment of a patient’s immune function is critical in many clinical situations. In complex clinical immune dysfunction like sepsis, which results from a loss of immune homeostasis due to microbial infection, a plethora of pro- and anti-inflammatory stimuli may occur consecutively or simultaneously. Thus, any immunomodulatory therapy would require in-depth knowledge of an individual patient’s immune status at a given time. Whereas lab-based immune profiling often relies solely on quantification of cell numbers, we used an ex vivo whole-blood infection model in combination with biomathematical modeling to quantify functional parameters of innate immune cells in blood from patients undergoing cardiac surgery. These patients experience a well-characterized inflammatory insult, which results in mitigation of the pathogen-specific response patterns towards Staphylococcus aureus and Candida albicans that are characteristic of healthy people and our patients at baseline. This not only interferes with the elimination of these pathogens from blood, but also selectively augments the escape of C. albicans from phagocytosis. In summary, our model could serve as a valuable functional immune assay for recording and evaluating innate responses to infection.

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Ex Vivo Immune Profiling in Patient Blood Enables Quantification of Innate Immune Effector Functions

10.21203/rs.3.rs-237261/v1 ◽

2021 ◽

Author(s):

Teresa Lehnert ◽

Ines Leonhardt ◽

Sandra Timme ◽

Daniel Thomas-Rüddel ◽

Frank Bloos ◽

...

Keyword(s):

Ex Vivo ◽

Innate Immune ◽

Infection Model ◽

Specific Response ◽

Response Patterns ◽

Microbial Infection ◽

Immune Effector ◽

Pathogen Elimination ◽

Inflammatory Stimuli ◽

Immune Profiling

Abstract Assessment of a patient’s immune function is critical in many clinical situations. One prominent example is sepsis, which results from a loss of immune homeostasis due to microbial infection and is characterized by a plethora of pro- and anti-inflammatory stimuli that may occur consecutively or simultaneously. Thus, any immunomodulatory therapy would require in depth knowledge of an individual patient’s immune status at a given time. Whereas lab-test based immune profiling often relies solely on quantification of cell numbers, we have used an ex vivo whole-blood infection model in combination with biomathematical modeling to quantify functional parameters of innate immune cells in blood from patients undergoing cardiac surgery. These patients experience a well characterized inflammatory insult, which results in mitigation of pathogen-specific response patterns towards Staphylococcus aureus and Candida albicans that are characteristic for healthy people and baseline results in our patients. This does not only interfere with pathogen elimination from blood but also selectively augments the escape of C. albicans from phagocytosis. In summary, our model gives insight into immune functionality and might serve as a functional immune assay to record and evaluate innate response patterns towards infection.

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Ex vivo Immune Profiling in Patient Blood enables Quantification of innate immune Effector Functions

10.1101/2020.10.01.322032 ◽

2020 ◽

Author(s):

Teresa Lehnert ◽

Ines Leonhardt ◽

Sandra Timme ◽

Daniel Thomas-Rüddel ◽

Frank Bloos ◽

...

Keyword(s):

Cardiac Surgery ◽

Whole Blood ◽

Immune Cell ◽

Ex Vivo ◽

Innate Immune ◽

Response Patterns ◽

Inflammatory Stimulus ◽

Functional Parameters ◽

Immune Profiling ◽

Biomathematical Modeling

AbstractThe immune response towards infection is a dynamic system combating invading pathogens to maintain homeostasis and the integrity of the body. Unbalanced immune response profiles determine many clinical syndromes including sepsis and thus present a major challenge in management of life threatening infections. Consequently, there is a high demand to determine a patient’s immune status and identifying functional parameters for immune dysfunction.Here, we quantified the global functional status of human innate immune responses by using a human whole-blood model of infection combined with biomathematical modeling. By determining functional parameters of innate immune cell populations after ex vivo whole-blood bacterial (Staphylococcus aureus) and fungal (Candida albicans) infection, we examined cell-specific functional parameters including migration rates or phagocytosis rates in patients that underwent cardiac surgery with extracorporeal circulation. This intervention is known to pose a transient but strong inflammatory stimulus. In addition to a post-operative increase in white blood cell count mainly caused by mobilization of immature neutrophils we find that the surgery induced pro-inflammatory stimulus results in a mitigation of pathogen-specific response patterns that are characteristic for healthy people and baseline results in our patients. Moreover, our model revealed changing rates for pathogen immune evasion, indicating increased inter-pathogenic differences after surgery. This effect was specific for C. albicans and could not be observed for S. aureus. In summary, our model gives insight into immune functionality and might serve as a functional immune assay to record and evaluate innate response patterns towards infection.Author summaryAssessment of a patient’s immune function is critical in many clinical situations. One prominent example is sepsis, which results from a loss of immune homeostasis due to microbial infection. Sepsis is characterized by a plethora of pro- and anti-inflammatory simuli that may occur consecutively or simultaneously and thus any immunomodulatory therapy would require in depth knowledge of an individual patient’s immune status at a given time. Whereas lab-test based immune profiling often relies solely on quantification of cell numbers, we have used an ex vivo whole-blood infection model in combination with biomathematical modeling to quantify functional parameters of innate immune cells in patient blood. A small blood sample of patients undergoing cardiac surgery, which is known to constitute an inflammatory stimulus was infected ex vivo. Functional immune cell parameters were determined using a combination of experimental assays and biomathematical modeling. We show that these parameters change after an inflammatory insult triggered by cardiac surgery and extracorporeal circulation. This does not only interfere with pathogen elimination from blood but also selectively augments the escape of the fungal pathogen Candida albicans from phagocytosis.

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Faculty Opinions recommendation of Caspase-1-induced pyroptosis is an innate immune effector mechanism against intracellular bacteria.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.6275956.6396054 ◽

2010 ◽

Author(s):

Andreas Baumler ◽

Sebastian Winter

Keyword(s):

Innate Immune ◽

Intracellular Bacteria ◽

Immune Effector ◽

Effector Mechanism ◽

Caspase 1 ◽

Innate Immune Effector

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Faculty Opinions recommendation of Actin polymerization as a key innate immune effector mechanism to control Salmonella infection.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.725246829.793502006 ◽

2015 ◽

Author(s):

Egil Lien

Keyword(s):

Actin Polymerization ◽

Innate Immune ◽

Salmonella Infection ◽

Immune Effector ◽

Effector Mechanism ◽

Innate Immune Effector

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Masking of β(1-3)-Glucan in the Cell Wall of Candida albicans from Detection by Innate Immune Cells Depends on Phosphatidylserine

Infection and Immunity ◽

10.1128/iai.01612-14 ◽

2014 ◽

Vol 82 (10) ◽

pp. 4405-4413 ◽

Cited By ~ 32

Author(s):

Sarah E. Davis ◽

Alex Hopke ◽

Steven C. Minkin ◽

Anthony E. Montedonico ◽

Robert T. Wheeler ◽

...

Keyword(s):

Cell Wall ◽

Candida Albicans ◽

De Novo ◽

Invasive Disease ◽

Innate Immune ◽

Dependent Manner ◽

Content Type ◽

Immune Effector ◽

Host Interactions ◽

Innate Immune Effector

ABSTRACTThe virulence ofCandida albicansin a mouse model of invasive candidiasis is dependent on the phospholipids phosphatidylserine (PS) and phosphatidylethanolamine (PE). Disruption of the PS synthase geneCHO1(i.e.,cho1Δ/Δ) eliminates PS and blocks thede novopathway for PE biosynthesis. In addition, thecho1Δ/Δ mutant's ability to cause invasive disease is severely compromised. Thecho1Δ/Δ mutant also exhibits cell wall defects, and in this study, it was determined that loss of PS results in decreased masking of cell wall β(1-3)-glucan from the immune system. In wild-typeC. albicans, the outer mannan layer of the wall masks the inner layer of β(1-3)-glucan from exposure and detection by innate immune effector molecules like the C-type signaling lectin Dectin-1, which is found on macrophages, neutrophils, and dendritic cells. Thecho1Δ/Δ mutant exhibits increases in exposure of β(1-3)-glucan, which leads to greater binding by Dectin-1 in both yeast and hyphal forms. The unmasking of β(1-3)-glucan also results in increased elicitation of TNF-α from macrophages in a Dectin-1-dependent manner. The role of phospholipids in fungal pathogenesis is an emerging field, and this is the first study showing that loss of PS inC. albicansresults in decreased masking of β(1-3)-glucan, which may contribute to our understanding of fungus-host interactions.

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Neutrophil Extracellular Traps Serve as Key Effector Molecules in the Protection Against Phialophora verrucosa

Mycopathologia ◽

10.1007/s11046-021-00554-0 ◽

2021 ◽

Vol 186 (3) ◽

pp. 367-375

Author(s):

Qin Liu ◽

Wenjuan Yi ◽

Si Jiang ◽

Jiquan Song ◽

Pin Liang

Keyword(s):

Neutrophil Extracellular Traps ◽

Innate Immune ◽

Immune Effector ◽

Phialophora Verrucosa ◽

Extracellular Traps ◽

Sytox Green ◽

Innate Immune Effector ◽

Pathogen Control ◽

Extracellular Structures

AbstractPhialophora verrucosa (P. verrucosa) is a pathogen that can cause chromoblastomycosis and phaeohyphomycosis. Recent evidence suggests that neutrophils can produce neutrophil extracellular traps (NETs) that can protect against invasive pathogens. As such, we herein explored the in vitro functional importance of P. verrucosa-induced NET formation. By assessing the co-localization of neutrophil elastase and DNA, we were able to confirm the formation of classical NETs entrapping P. verrucosa specimens. Sytox Green was then used to stain these NETs following neutrophil infection with P. verrucosa in order to quantify the formation of these extracellular structures. NET formation was induced upon neutrophil exposure to both live, UV-inactivated, and dead P. verrucosa fungi. The ability of these NETs to kill fungal hyphae and conidia was demonstrated through MTT and pouring plate assays, respectively. Overall, our results confirmed that P. verrucosa was able to trigger the production of NETs, suggesting that these extracellular structures may represent an important innate immune effector mechanism controlling physiological responses to P. verrucosa infection, thereby aiding in pathogen control during the acute phases of infection.

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