Severe Systemic Infection: A Case Study of a German Long-Term Resident in French Guyana.

is a Gram-negative, facultative anaerobe proteobacterium. Its natural habitat is water and soil in tropical and subtropical regions. Human infections are characterized by rapid dissemination that can lead to high fatality rates.

Deciphering the Plasmodium falciparum malaria-specific CD4+ T-cell response: ex vivo detection of high frequencies of PD-1+TIGIT+ EXP1-specific CD4+ T cells using a novel HLA-DR11-restricted MHC class II tetramer.

Relatively little is known about the ex vivo frequency and phenotype of the Plasmodium falciparum-specific CD4+ T-cell response in humans. The exported protein 1 (EXP1) is expressed by plasmodia at both, the liver stage and blood stage, of infection making it a potential target for CD4+ and CD8+ effector T cells. Here, a fluorochrome-labelled HLA-DRB1∗11:01-restriced MHC class II tetramer derived from the P.

T cells expressing multiple co-inhibitory molecules in acute malaria are not exhausted but exert a suppressive function in mice.

Overwhelming activation of T cells in acute malaria is associated with severe outcomes. Thus, counter-regulation by anti-inflammatory mechanisms is indispensable for an optimal resolution of disease. Using Plasmodium berghei ANKA (PbA) infection of C57BL/6 mice, we performed a comprehensive analysis of co-inhibitory molecules expressed on CD4 and CD8 T cells using an unbiased cluster analysis approach.

Cytotoxic T Cell-Derived Granzyme B Is Increased in Severe Malaria.

In malaria, CD8 T cells play a double-edged role. Liver-stage specific CD8 T cells can confer protection, as has been shown in several vaccine studies. Blood-stage specific CD8 T cells, on the other hand, contribute to the development of cerebral malaria in murine models of malaria.

Atypical memory B-cells are associated with anemia through anti-phosphatidylserine antibodies.

Anemia is a common complication of malaria that is characterized by the loss of infected and uninfected erythrocytes. In mouse malaria models, clearance of uninfected erythrocytes is promoted by autoimmune anti-phosphatidylserine (PS) antibodies produced by T-betB-cells, which bind to exposed PS in erythrocytes, but the mechanism in patients is still unclear. In patients with anemia, we show that atypical memory FcRL5T-bet B-cells are expanded and associate both with higher levels of anti-PS antibodies in plasma and with the development of anemia in these patients.

Author Correction: Differential expression pattern of co-inhibitory molecules on CD4 T cells in uncomplicated versus complicated malaria.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

Differential expression pattern of co-inhibitory molecules on CD4 T cells in uncomplicated versus complicated malaria.

The immune response of malaria patients is a main factor influencing the clinical severity of malaria. A tight regulation of the CD4 T cell response or the induction of tolerance have been proposed to contribute to protection from severe or clinical disease. We therefore compared the CD4 T cell phenotypes of Ghanaian children with complicated malaria, uncomplicated malaria, asymptomatic Plasmodium falciparum (Pf) infection or no infection.

Protein structure shapes immunodominance in the CD4 T cell response to yellow fever vaccination.

The live attenuated yellow fever (YF) vaccine is a highly effective human vaccine and induces long-term protective neutralizing antibodies directed against the viral envelope protein E. The generation of such antibodies requires the help of CD4 T cells which recognize peptides derived from proteins in virus particles internalized and processed by E-specific B cells. The CD4 T helper cell response is restricted to few immunodominant epitopes, but the mechanisms of their selection are largely unknown.

Acute Malaria Induces PD1+CTLA4+ Effector T Cells with Cell-Extrinsic Suppressor Function.

In acute Plasmodium falciparum (P. falciparum) malaria, the pro- and anti-inflammatory immune pathways must be delicately balanced so that the parasitemia is controlled without inducing immunopathology. An important mechanism to fine-tune T cell responses in the periphery is the induction of coinhibitory receptors such as CTLA4 and PD1.

IL-22 dampens the T cell response in experimental malaria.

A tight regulation between the pro- and anti-inflammatory immune responses during plasmodial infection is of crucial importance, since a disruption leads to severe malaria pathology. IL-22 is a member of the IL-10 cytokine family, which is known to be highly important in immune regulation. We could detect high plasma levels of IL-22 in Plasmodium falciparum malaria as well as in Plasmodium berghei ANKA (PbA)-infected C57BL/6J mice.

Rapid-Antigen Test Negative Malaria in a Traveler Returning From Thailand, Molecularly Diagnosed as Plasmodium knowlesi.

Plasmodium knowlesi has been identified in the last decade as a fifth species causing malaria in areas of South East Asia. Due to its short erythrocytic cycle, rapid development of high parasitemia and severe manifestations are frequently observed. Therefore, prompt diagnosis of infection is essential to prevent complications, but the low sensitivity of rapid diagnostic tests for P knowlesi pose a diagnostic challenge in acute settings.

Human cord blood CD4+CD25hi regulatory T cells suppress prenatally acquired T cell responses to Plasmodium falciparum antigens.

In malaria endemic regions, a fetus is often exposed in utero to Plasmodium falciparum blood-stage Ags. In some newborns, this can result in the induction of immune suppression. We have previously shown these modulated immune responses to persist postnatally, with a subsequent increase in a child's susceptibility to infection.

Immunizing school-age children and adolescents: experience from low- and middle-income countries.

Objective: Given the increased attention on the need for booster immunizations of older children and adolescents, as well as new primary vaccine series that specifically target school-age children and adolescents, we reviewed the current state of vaccine delivery to school-age children and adolescents in low- and middle-income countries.

Methods: We searched the published literature and unpublished sources for articles, meeting presentations, technical reports and program documents related to immunization policies and programs for school-age children and/or adolescents between 6 and 19 years of age in low- and middle-income countries.

Findings: We found several examples of ongoing school-age children and adolescent immunization in low- and middle-income countries.