A distinct Borrelia clade within the relapsing fever group from cat-infesting Haemaphysalis semermis Neumann 1901 (Acari: Ixodidae).

An undescribed relapsing fever group Borrelia species was detected in a male Haemaphysalis semermis tick infesting a rural cat in an indigenous population in Pahang National Park, Peninsular Malaysia. The 16 S rRNA gene sequence revealed close similarity of this variant to several undescribed Borrelia species and Borrelia theileri, with genetic distances ranging from 0.58 to 0.

Molecular detection of spotted fever group rickettsiae in ticks from Cameroon.

In western and eastern Africa, rickettsioses are one cause of fever in humans. Little is known regarding the presence of Rickettsia sp. in northern Cameroon.

Tick (Amblyomma chabaudi) infestation of endemic tortoises in southwest Madagascar and investigation of tick-borne pathogens.

Little is known about the role of endemic ticks as vectors for bacterial and protozoan pathogens for animals and humans in Madagascar and their interaction in anthropogenic habitats where humans, their livestock and native Malagasy species (vectors and hosts) come into more frequent contact than in natural forest ecosystems. The aims of the study were (1) to test whether habitat degradation is associated with increased infestation of tortoises by ticks and (2) to investigate whether ticks carried Babesia, Borrelia or Rickettsia species that might be pathogenic for humans and livestock. We studied hard ticks of two endemic Malagasy tortoises, Astrochelys radiata and Pyxis arachnoides in March and April 2013 in southwest Madagascar.

High detection rate of Rickettsia africae in Amblyomma variegatum but low prevalence of anti-rickettsial antibodies in healthy pregnant women in Madagascar.

Tick-borne spotted fever group (SFG) rickettsioses are emerging infectious diseases in Sub-Saharan Africa. In Madagascar, the endemicity of tick-borne rickettsiae and their vectors has been incompletely studied. The first part of the present study was conducted in 2011 and 2012 to identify potential anthropophilic tick vectors for SFG rickettsiae on cattle from seven Malagasy regions, and to detect and characterize rickettsiae in these ticks.

Priming of CD8+ and CD4+ T cells in experimental leishmaniasis is initiated by different dendritic cell subtypes.

The biological role of Langerin+ dendritic cells (DCs) such as Langerhans cells and a subset of dermal DCs (dDCs) in adaptive immunity against cutaneous pathogens remains enigmatic. Thus, we analyzed the impact of Langerin+ DCs in adaptive T cell-mediated immunity toward Leishmania major parasites in a Lang-DTR mouse model that allows conditional diphtheria toxin (DT)-induced ablation of Langerin+ DCs in vivo. For the first time, infection experiments with DT-treated Lang-DTR mice revealed that proliferation of L.

Hsp60-mediated T cell stimulation is independent of TLR4 and IL-12.

Heat shock protein (Hsp) 60 is thought to function as endogenous danger signal by activating professional antigen-presenting cells (APC) through toll-like receptor (TLR) 4 and CD14, a mechanism that is also used by bacterial LPS. We recently showed that Hsp60 binds LPS and enhances LPS-induced immune stimulation. On the other hand, we also observed immune stimulation by Hsp60 independent of LPS which was partially mediated by Hsp60-induced IFN alpha.

Transgenic expression of a CD83-immunoglobulin fusion protein impairs the development of immune-competent CD4-positive T cells.

The murine transmembrane glycoprotein CD83 is an important regulator for both thymic T cell maturation and peripheral T cell response. CD83 deficiency leads to a block in the thymic maturation of CD4-positive T cells, and interference with peripheral CD83/CD83 ligand interaction by addition of soluble CD83 suppresses immune responses in vivo and in vitro. Here we report the generation of a mouse transgenic for a fusion protein consisting of the extracellular domain of murine CD83 fused to the constant part of human IgG1 heavy chain.

Lipopolysaccharide-free heat shock protein 60 activates T cells.

A possible function of eukaryotic heat shock protein 60 (Hsp60) as endogenous danger signal has been controversially discussed in the past. Hsp60 was shown to induce the secretion of proinflammatory cytokines in professional antigen-presenting cells and to enhance the activation of T cells in primary stimulation. However, in vitro activation of macrophages by Hsp60 was attributed to contaminating endotoxin in the recombinant Hsp60 protein preparations.