School of Mathematics and Statistics - Research Publications

Permanent URI for this collection

http://hdl.handle.net/11343/294

Filters

2015 - 2019 1 2020 - 2022 1
2
Reset filters

Settings
Statistics
Citations
Author: Cowman, Alan × Author: Smyth, Gordon ×

Search Results

Now showing 1 - 2 of 2
  • Item
    Thumbnail Image
    Molecular profiling reveals features of clinical immunity and immunosuppression in asymptomatic P. falciparum malaria
    Studniberg, S ; Ioannidis, LJ ; Utami, RAS ; Trianty, L ; Liao, Y ; Abeysekera, W ; Li-Wai-Suen, CSN ; Pietrzak, HM ; Healer, J ; Puspitasari, AM ; Apriyanti, D ; Coutrier, F ; Poespoprodjo, JR ; Kenangalem, E ; Andries, B ; Prayoga, P ; Sariyanti, N ; Smyth, GK ; Cowman, AF ; Price, RN ; Noviyanti, R ; Shi, W ; Garnham, AL ; Hansen, DS (WILEY, 2022-04)
    Clinical immunity to P. falciparum malaria is non-sterilizing, with adults often experiencing asymptomatic infection. Historically, asymptomatic malaria has been viewed as beneficial and required to help maintain clinical immunity. Emerging views suggest that these infections are detrimental and constitute a parasite reservoir that perpetuates transmission. To define the impact of asymptomatic malaria, we pursued a systems approach integrating antibody responses, mass cytometry, and transcriptional profiling of individuals experiencing symptomatic and asymptomatic P. falciparum infection. Defined populations of classical and atypical memory B cells and a TH2 cell bias were associated with reduced risk of clinical malaria. Despite these protective responses, asymptomatic malaria featured an immunosuppressive transcriptional signature with upregulation of pathways involved in the inhibition of T-cell function, and CTLA-4 as a predicted regulator in these processes. As proof of concept, we demonstrated a role for CTLA-4 in the development of asymptomatic parasitemia in infection models. The results suggest that asymptomatic malaria is not innocuous and might not support the induction of immune processes to fully control parasitemia or efficiently respond to malaria vaccines.
  • Item
    Thumbnail Image
    An aspartyl protease defines a novel pathway for export of Toxoplasma proteins into the host cell
    Coffey, MJ ; Sleebs, BE ; Uboldi, AD ; Garnham, A ; Franco, M ; Marino, ND ; Panas, MW ; Ferguson, DJP ; Enciso, M ; O'Neill, MT ; Lopaticki, S ; Stewart, RJ ; Dewson, G ; Smyth, GK ; Smith, BJ ; Masters, SL ; Boothroyd, JC ; Boddey, JA ; Tonkin, CJ (ELIFE SCIENCES PUBLICATIONS LTD, 2015-11-18)
    Infection by Toxoplasma gondii leads to massive changes to the host cell. Here, we identify a novel host cell effector export pathway that requires the Golgi-resident aspartyl protease 5 (ASP5). We demonstrate that ASP5 cleaves a highly constrained amino acid motif that has similarity to the PEXEL-motif of Plasmodium parasites. We show that ASP5 matures substrates at both the N- and C-terminal ends of proteins and also controls trafficking of effectors without this motif. Furthermore, ASP5 controls establishment of the nanotubular network and is required for the efficient recruitment of host mitochondria to the vacuole. Assessment of host gene expression reveals that the ASP5-dependent pathway influences thousands of the transcriptional changes that Toxoplasma imparts on its host cell. All these changes result in attenuation of virulence of Δasp5 tachyzoites in vivo. This work characterizes the first identified machinery required for export of Toxoplasma effectors into the infected host cell.