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  1. Article ; Online: ICOS signaling promotes a secondary humoral response after re-challenge with Plasmodium chabaudi chabaudi AS.

    Leah E Latham / Daniel J Wikenheiser / Jason S Stumhofer

    PLoS Pathogens, Vol 16, Iss 4, p e

    2020  Volume 1008527

    Abstract: The co-stimulatory molecule ICOS is associated with the induction and regulation of T helper cell responses, including the differentiation of follicular helper T (Tfh) cells and the formation and maintenance of memory T cells. However, the role of ICOS ... ...

    Abstract The co-stimulatory molecule ICOS is associated with the induction and regulation of T helper cell responses, including the differentiation of follicular helper T (Tfh) cells and the formation and maintenance of memory T cells. However, the role of ICOS signaling in secondary immune responses is largely unexplored. Here we show that memory T cell formation and maintenance are influenced by persistent infection with P. chabaudi chabaudi AS infection, as memory T cell numbers decline in wild-type and Icos-/- mice after drug-clearance. Following drug-clearance Icos-/- mice display a relapsing parasitemia that occurs more frequently and with higher peaks compared to wild-type mice after re-challenge. The secondary immune response in Icos-/- mice is characterized by significant impairment in the expansion of effector cells with a Tfh-like phenotype, which is associated with a diminished and delayed parasite-specific Ab response and the absence of germinal centers. Similarly, the administration of an anti-ICOSL antagonizing antibody to wild-type mice before and after reinfection with P. c. chabaudi AS leads to an early defect in Tfh cell expansion and parasite-specific antibody production, confirming a need for ICOS-ICOSL interactions to promote memory B cell responses. Furthermore, adoptive transfer of central memory T (TCM) cells from wild-type and Icos-/- mice into tcrb-/- mice to directly evaluate the ability of TCM cells to give rise to Tfh cells revealed that TCM cells from wild-type mice acquire a mixed Th1- and Tfh-like phenotype after P. c. chabaudi AS infection. While TCM cells from Icos-/- mice expand and display markers of activation to a similar degree as their WT counterparts, they displayed a reduced capacity to upregulate markers indicative of a Tfh cell phenotype, resulting in a diminished humoral response. Together these findings verify that ICOS signaling in memory T cells plays an integral role in promoting T cell effector responses during secondary infection with P. c. chabaudi AS.
    Keywords Immunologic diseases. Allergy ; RC581-607 ; Biology (General) ; QH301-705.5
    Subject code 570
    Language English
    Publishing date 2020-04-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Towards rainbow portable Cytophone with laser diodes for global disease diagnostics

    Hind J. Jawad / Aayire C. Yadem / Yulian A. Menyaev / Mustafa Sarimollaoglu / Jillian N. Armstrong / Fumiya Watanabe / Alexandru S. Biris / Jason S. Stumhofer / Dmitry Nedosekin / James Y. Suen / Sunil Parikh / Vladimir P. Zharov

    Scientific Reports, Vol 12, Iss 1, Pp 1-

    2022  Volume 17

    Abstract: Abstract In vivo, Cytophone has demonstrated the capability for the early diagnosis of cancer, infection, and cardiovascular disorders through photoacoustic detection of circulating disease markers directly in the bloodstream with an unprecedented 1,000- ... ...

    Abstract Abstract In vivo, Cytophone has demonstrated the capability for the early diagnosis of cancer, infection, and cardiovascular disorders through photoacoustic detection of circulating disease markers directly in the bloodstream with an unprecedented 1,000-fold improvement in sensitivity. Nevertheless, a Cytophone with higher specificity and portability is urgently needed. Here, we introduce a novel Cytophone platform that integrates a miniature multispectral laser diode array, time-color coding, and high-speed time-resolved signal processing. Using two-color (808 nm/915 nm) laser diodes, we demonstrated spectral identification of white and red clots, melanoma cells, and hemozoin in malaria-infected erythrocytes against a blood background and artifacts. Data from a Plasmodium yoelii murine model and cultured human P. falciparum were verified in vitro with confocal photothermal and fluorescent microscopy. With these techniques, we detected infected cells within 4 h after invasion, which makes hemozoin promising as a spectrally selective marker at the earliest stages of malaria progression. Along with the findings from our previous application of Cytophone with conventional lasers for the diagnosis of melanoma, bacteremia, sickle anemia, thrombosis, stroke, and abnormal hemoglobin forms, this current finding suggests the potential for the development of a portable rainbow Cytophone with multispectral laser diodes for the identification of these and other diseases.
    Keywords Medicine ; R ; Science ; Q
    Subject code 290 ; 610
    Language English
    Publishing date 2022-05-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: IL-21 is required for optimal antibody production and T cell responses during chronic Toxoplasma gondii infection.

    Jason S Stumhofer / Jonathan S Silver / Christopher A Hunter

    PLoS ONE, Vol 8, Iss 5, p e

    2013  Volume 62889

    Abstract: Previous studies have indicated that Il21r (-/-) mice chronically infected with Toxoplasma gondii display a defect in serum IgG; however, the basis for this antibody defect was not defined and questions remain about the role of IL-21 in promoting the ... ...

    Abstract Previous studies have indicated that Il21r (-/-) mice chronically infected with Toxoplasma gondii display a defect in serum IgG; however, the basis for this antibody defect was not defined and questions remain about the role of IL-21 in promoting the production of IL-10, which is required to limit infection-induced pathology during toxoplasmosis. Therefore, Il21 (-/-) mice were challenged with T. gondii to determine whether IL-21 impacts the parasite-specific CD8(+) T cell response, its contribution to thymus-dependent antibody production after infection, and balance between protective and pathogenic responses. Whereas IL-21 has been implicated in the differentiation of IL-10 producing CD4(+) T cells no immune-mediated pathology was evident in Il21 (-/-) mice during the acute response, nor was there a defect in the development of this population in chronically infected Il21 (-/-) mice. However, Il21 (-/-) mice displayed a defect in IgG production after infection that correlated with a decrease in GC B cell numbers, the CD4(+) and CD8(+) T cell numbers in the brain were reduced over the course of the chronic infection leading to a decrease in total IFN-γ production and an increase in parasite numbers associated with susceptibility to toxoplasmic encephalitis. Together, these results identify a key role for IL-21 in shaping the humoral and cellular response to T. gondii, but indicate that IL-21 has a limited role in regulating immunopathology.
    Keywords Medicine ; R ; Science ; Q
    Subject code 570
    Language English
    Publishing date 2013-01-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Timed action of IL-27 protects from immunopathology while preserving defense in influenza.

    Francesca Diane M Liu / Elisabeth E Kenngott / Micha F Schröter / Anja Kühl / Silke Jennrich / Ralf Watzlawick / Ute Hoffmann / Thorsten Wolff / Stephen Norley / Alexander Scheffold / Jason S Stumhofer / Christiaan J M Saris / Jan M Schwab / Christopher A Hunter / Gudrun F Debes / Alf Hamann

    PLoS Pathogens, Vol 10, Iss 5, p e

    2014  Volume 1004110

    Abstract: Infection with influenza virus can result in massive pulmonary infiltration and potentially fatal immunopathology. Understanding the endogenous mechanisms that control immunopathology could provide a key to novel adjunct therapies for this disease. Here ... ...

    Abstract Infection with influenza virus can result in massive pulmonary infiltration and potentially fatal immunopathology. Understanding the endogenous mechanisms that control immunopathology could provide a key to novel adjunct therapies for this disease. Here we show that the cytokine IL-27 plays a crucial role in protection from exaggerated inflammation during influenza virus infection. Using Il-27ra-/- mice, IL-27 was found to limit immunopathology, neutrophil accumulation, and dampened TH1 or TH17 responses via IL-10-dependent and -independent pathways. Accordingly, the absence of IL-27 signals resulted in a more severe disease course and in diminished survival without impacting viral loads. Consistent with the delayed expression of endogenous Il-27p28 during influenza, systemic treatment with recombinant IL-27 starting at the peak of virus load resulted in a major amelioration of lung pathology, strongly reduced leukocyte infiltration and improved survival without affecting viral clearance. In contrast, early application of IL-27 impaired virus clearance and worsened disease. These findings demonstrate the importance of IL-27 for the physiological control of immunopathology and the potential value of well-timed IL-27 application to treat life-threatening inflammation during lung infection.
    Keywords Immunologic diseases. Allergy ; RC581-607 ; Biology (General) ; QH301-705.5
    Subject code 570
    Language English
    Publishing date 2014-05-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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