The severity of malarial anaemia in infections of BALB/c mice is determined independently of the number of circulating parasites-2

Drop in Hb level of the blood relative to day 0 measurements in BALB/c and BALB/c RAG2-/- animals. The bars in a) to c) represent the average, and the error bars the SEM, of the cumulative values of 15 BALB/c AS-infected animals (black square) 15 RAG2-/- AS- infected animals (open square) from 3 experiments. d) and e) Residual amount of anaemia (once experiment has been taken into account) in infection of BALB/c mice (black circle) and RAG2-/- mice plotted (open circle) against the peak number of circulating pRBCs for each mouse. In d) and e) the solid line represents the best-fit linear regression line. The dashed line highlights the residual anaemia observed once the data is normalized for experimental variation in the magnitude of RBC loss (ANOVA model "RBC loss = experiment"). Therefore the solid best-fit regression line shows the extent to which peak pRBC numbers correlate with the drop in circulating RBCs once experiment has been accounted for (residual change in RBC number). The black dots represent BALB/c animals and the white dots represent RAG2-/- animals.<p><b>Copyright information:</b></p><p>Taken from "The severity of malarial anaemia in infections of BALB/c mice is determined independently of the number of circulating parasites"</p><p>http://www.malariajournal.com/content/7/1/68</p><p>Malaria Journal 2008;7():68-68.</p><p>Published online 25 Apr 2008</p><p>PMCID:PMC2412895.</p><p></p

The severity of malarial anaemia in infections of BALB/c mice is determined independently of the number of circulating parasites-0

Drop in Hb level of the blood relative to day 0 measurements in BALB/c and BALB/c RAG2-/- animals. The bars in a) to c) represent the average, and the error bars the SEM, of the cumulative values of 15 BALB/c AS-infected animals (black square) 15 RAG2-/- AS- infected animals (open square) from 3 experiments. d) and e) Residual amount of anaemia (once experiment has been taken into account) in infection of BALB/c mice (black circle) and RAG2-/- mice plotted (open circle) against the peak number of circulating pRBCs for each mouse. In d) and e) the solid line represents the best-fit linear regression line. The dashed line highlights the residual anaemia observed once the data is normalized for experimental variation in the magnitude of RBC loss (ANOVA model "RBC loss = experiment"). Therefore the solid best-fit regression line shows the extent to which peak pRBC numbers correlate with the drop in circulating RBCs once experiment has been accounted for (residual change in RBC number). The black dots represent BALB/c animals and the white dots represent RAG2-/- animals.<p><b>Copyright information:</b></p><p>Taken from "The severity of malarial anaemia in infections of BALB/c mice is determined independently of the number of circulating parasites"</p><p>http://www.malariajournal.com/content/7/1/68</p><p>Malaria Journal 2008;7():68-68.</p><p>Published online 25 Apr 2008</p><p>PMCID:PMC2412895.</p><p></p

The severity of malarial anaemia in infections of BALB/c mice is determined independently of the number of circulating parasites-1

Er of circulating parasites and d) % of pRBC over the same time scale in AS-infected mice (black circle), CB-infected mice (open circle) and naive control animals (-). For each day the circles in a) to d) represent the average and the error bars the standard error of the mean (SEM) of 5 animals from experiment 2. e) and f) residual number of circulating RBCs after experiment and clone have been taken into consideration plotted against peak percentage parasitemia (e) or peak number of pRBC (f) for all three experiments. Each symbol represents the values for a single mouse infected with clone AS (black circle) or clone CB (open circle). The solid lines represent the best fit linear regression line in each case, and the dashed lines highlight the residual anaemia observed once the data is normalized for experimental and clonal variation in the magnitude of RBC loss (ANOVA model "RBC loss = experiment+clone").<p><b>Copyright information:</b></p><p>Taken from "The severity of malarial anaemia in infections of BALB/c mice is determined independently of the number of circulating parasites"</p><p>http://www.malariajournal.com/content/7/1/68</p><p>Malaria Journal 2008;7():68-68.</p><p>Published online 25 Apr 2008</p><p>PMCID:PMC2412895.</p><p></p

Chronic phase of a <i>P. chabaudi</i> infection enhances CD4⁺ Memory T cell activation and expansion.

<p>Mice were infected with 10⁵<i>P. chabaudi</i> (AS). On days 30-34 one group of mice was treated with chloroquine (<b>+CQ</b>), which quickly eliminated the infection, while the other mice retained a chronic infection (<b>-CQ</b>). <b>A)</b> Half of each group was re-infected with 10⁵<i>P. chabaudi</i> day 60 post-infection, and splenocytes were analyzed by flow cytometry on day 63 for CD4, CD44, CD62L and expression of the early activation marker CD69 (<b>A–C</b>) or incorporation of BrdU dosed into the water days 60–65 as an indicator of homeostatic proliferation (<b>D, E</b>), CD69 expression on central memory T cells (Tcm, CD44^hiCD62^lo) and effector memory T cells (Tem, CD44^hiCD62L^int/hi) are shown. Dotted lines represent chloroquine treated mice (+CQ) while bold lines represent chronic infection (-CQ). Data shown is the average of 4–5 mice per group and experiment was repeated twice with similar results. <b>*</b> indicates p≤0.05, <b>**</b> p≤0.01.</p

Chronic infection reduces IL-7Rα^hi memory cells in both memory subsets.

<p>Mice were infected with 10⁵<i>P. chabaudi</i>. Days 30–34 half of the mice were treated with chloroquine (<b>+CQ</b>), while the other mice retained a chronic infection (<b>-CQ</b>). 2.5 months after infection, splenocytes were analyzed by flow cytometry for CD4, CD44, CD62L and (<b>A, B</b>) IL-7Rα (CD127) or incorporation of BrdU dosed into the water days 62–72 as an indicator of homeostatic proliferation, (<b>C, D</b>). Naïve cells (CD44^lo) were used as an internal control to set the quadrants (<b>B</b>, left). Dotted lines represent chloroquine treated mice (+CQ) while bold lines represent chronic infection (-CQ). Data shown is the average of 4–5 mice per group and experiment was repeated twice with similar results. Contour plots (10% with outliers) are gated as described on each plot and are from representative animals. <b>*</b> indicates p≤0.05, <b>**</b> p≤0.01.</p

Epigenetic reprogramming of <i>Plasmodium</i> within the mosquito.

<p>Reset: expression of subtelomeric multigene families is reset in the mosquito by epigenetic reprogramming of the zygote. This ensures that a parasite population will always express all multigene family members from the start of the erythrocytic cycle and gives merozoites the best possible chance of establishing a blood-stage infection every time they emerge from the liver (e.g., it may be beneficial to express all VSA upon liver egress, as a malaria-experienced host will have pre-existing antibodies that recognise a broad repertoire of variant antigens [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1004987#ppat.1004987.ref023" target="_blank">23</a>]). Select and switch: parasites that express (or switch to) multigene family members offering a survival advantage in their new host are retained, whereas parasites that silence these genes are lost through rounds of selection. In time, this leads to a parasite population expressing a narrow repertoire of multigene family members that promotes survival and chronicity. The further into the chronic phase of infection, the better adapted are parasites to their host. <i>Plasmodium</i> virulence therefore increases, and the need to reset gene expression also increases. Reset: in preparation for entry into the next host, all chromatin marks are again erased following gamete fusion. This model of gene expression provides a general mechanism by which all <i>Plasmodium</i> subtelomeric multigene families could be regulated by the mosquito.</p

Total numbers of splenic cells (a), CD4T cells (b) and CD4T cells producing cytokines, IFN-γ, IL-2, IL-4 and IL-10 (c-f respectively) in mice infected with (ER) on day 13 after infection

<p><b>Copyright information:</b></p><p>Taken from "Cytokine responses of CD4T cells during a (ER) blood-stage infection in mice initiated by the natural route of infection"</p><p>http://www.malariajournal.com/content/6/1/77</p><p>Malaria Journal 2007;6():77-77.</p><p>Published online 7 Jun 2007</p><p>PMCID:PMC1904224.</p><p></p> Mice were submitted to bites by infected mosquitoes (infect), previous bites by uninfected mosquitoes before infected mosquitoes (uninfect. + infect.), only bites by uninfected mosquitoes (uninfect.) and not bitten (naive). The values represent the means and standard errors of the means of 3 mice

Blood stage infections of (ER) in C57BlC57BL/6 mice initiated by bite of infected mosquitoes and injection of parasitized erythrocytes (pRBCs)

<p><b>Copyright information:</b></p><p>Taken from "Cytokine responses of CD4T cells during a (ER) blood-stage infection in mice initiated by the natural route of infection"</p><p>http://www.malariajournal.com/content/6/1/77</p><p>Malaria Journal 2007;6():77-77.</p><p>Published online 7 Jun 2007</p><p>PMCID:PMC1904224.</p><p></p> a) Course of infection after direct challenge with pRBC, and after infectious mosquito bites as described in the materials and methods (representative experiment of 3 performed). The values shown are the geometric means and standard errors of the parasitaemia from a minimum of five mice. b) Duration of the pre-patent period, peak parasitaemia and duration of infection. The values shown are the means and standard errors of the mean of a minimum of 15 mice

Antibodies used for <i>ex vivo</i> flow cytometry analysis.

a<p>Dump channel comprised of lineage markers to gate out non-relevant PBMC subsets.</p><p>n/a = not applicable.</p><p>BCR = B-cell receptor.</p

Effects of prior exposure to the bites of uninfected mosquitoes on a blood stage infection of (ER) transmitted by infected mosquitoes

<p><b>Copyright information:</b></p><p>Taken from "Cytokine responses of CD4T cells during a (ER) blood-stage infection in mice initiated by the natural route of infection"</p><p>http://www.malariajournal.com/content/6/1/77</p><p>Malaria Journal 2007;6():77-77.</p><p>Published online 7 Jun 2007</p><p>PMCID:PMC1904224.</p><p></p> a) Experimental procedure for the infection of mice with (ER) through the bites of infected mosquitoes, after being exposed to four weekly sessions of bites by uninfected mosquitoes. One group of mice was only submitted to infectious mosquito bites. b) Course of infection in mice submitted first to uninfected followed by infected mosquito bites (▲), and infected mosquito bites only (■). The infection was followed for 13 days at which time mice were sacrificed and FACS analysis performed (see Figure 4). c) Length of pre-patent period, and peak parasitaemia of mice submitted to uninfected and infected mosquito bites (□), and infected mosquito bites only (■). The values represent the means and standard errors of the means of at least 3 mice per group