The rodent parasite
is an important
model of malaria. The ability to produce chronic infections makes it particularly useful for investigating the development of anti-
immunity, as well as features ...associated with parasite virulence during both the acute and chronic phases of infection.
also undergoes asexual maturation (schizogony) and erythrocyte invasion in culture, so offers an experimentally-amenable
to
model for studying gene function and drug activity during parasite replication. To extend the usefulness of this model, we have further optimised transfection protocols and plasmids for
and generated stable, fluorescent lines that are free from drug-selectable marker genes. These mother-lines show the same infection dynamics as wild-type parasites throughout the lifecycle in mice and mosquitoes; furthermore, their virulence can be increased by serial blood passage and reset by mosquito transmission. We have also adapted the large-insert, linear
GEM vectors that have revolutionised the scale of experimental genetics in another rodent malaria parasite and used these to generate barcoded
gene-deletion and -tagging vectors for transfection in our fluorescent
mother-lines. This produces a tool-kit of
lines, vectors and transfection approaches that will be of broad utility to the research community.
The rodent parasite
Plasmodium chabaudi
is an important
in vivo
model of malaria. The ability to produce chronic infections makes it particularly useful for investigating the development of anti-
...Plasmodium
immunity, as well as features associated with parasite virulence during both the acute and chronic phases of infection.
P. chabaudi
also undergoes asexual maturation (schizogony) and erythrocyte invasion in culture, so offers an experimentally-amenable
in vivo
to
in vitro
model for studying gene function and drug activity during parasite replication. To extend the usefulness of this model, we have further optimised transfection protocols and plasmids for
P. chabaudi
and generated stable, fluorescent lines that are free from drug-selectable marker genes. These mother-lines show the same infection dynamics as wild-type parasites throughout the lifecycle in mice and mosquitoes; furthermore, their virulence can be increased by serial blood passage and reset by mosquito transmission. We have also adapted the large-insert, linear
Plasmo
GEM vectors that have revolutionised the scale of experimental genetics in another rodent malaria parasite and used these to generate barcoded
P. chabaudi
gene-deletion and –tagging vectors for transfection in our fluorescent
P. chabaudi
mother-lines. This produces a tool-kit of
P. chabaudi
lines, vectors and transfection approaches that will be of broad utility to the research community.
Highlights • Antigens are shared between liver and blood-stage malaria parasites. • Cross-stage antigens can mediate protection which is life cycle stage transcending. • Multi-stage malaria vaccine ...development should identify cross-stage antigens.
Background. Immunization of healthy volunteers during receipt of chemoprophylaxis with Plasmodium falciparum sporozoites (CPS-immunization) induces sterile protection from malaria. Antibody responses ...have long been known to contribute to naturally acquired immunity against malaria, but their association with sterile protection after whole sporozoite immunization is not well established. We therefore studied the induction and kinetics of malaria parasite antigen-specific antibodies and memory B-cells (MBCs) during CPS-immunization and their correlation with protection from challenge infection. Methods. We assessed humoral reactivity to 9 antigens representing different stages of the life cycle of P. falciparum by performing standardized MBC enzyme-linked immunospot and enzyme-linked immunosorbent assays on peripheral blood mononuclear cells and plasma samples from 38 Dutch volunteers enrolled in 2 randomized controlled clinical trials. Results. MBCs and antibodies recognizing pre-erythrocytic and cross-stage antigens were gradually acquired during CPS-immunization. The magnitude of these humoral responses did not correlate with protection but directly reflected parasite exposure in CPS-immunization and challenge. Conclusions. Humoral responses to the malarial antigens circumsporozoite protein, liver-stage antigen-1, apical membrane antigen-1, and merozoite surface protein-1 do not to predict protection from challenge infection but can be used as sensitive marker of recent parasite exposure. Clinical Trials Registration. NCT01236612 and NCT01218893
In the murine model of Leishmania major infection, resistance or susceptibility to the parasite has been associated with the development of a Th1 or Th2 type of immune response. Recently, however, ...the immunosuppressive effects of IL-10 have been ascribed a crucial role in the development of the different clinical correlates of Leishmania infection in humans. Since T cells and professional APC are important cellular sources of IL-10, we compared leishmaniasis disease progression in T cell-specific, macrophage/neutrophil-specific and complete IL-10-deficient C57BL/6 as well as T cell-specific and complete IL-10-deficient BALB/c mice. As early as two weeks after infection of these mice with L. major, T cell-specific and complete IL-10-deficient animals showed significantly increased lesion development accompanied by a markedly elevated secretion of IFN-γ or IFN-γ and IL-4 in the lymph nodes draining the lesions of the C57BL/6 or BALB/c mutants, respectively. In contrast, macrophage/neutrophil-specific IL-10-deficient C57BL/6 mice did not show any altered phenotype. During the further course of disease, the T cell-specific as well as the complete IL-10-deficient BALB/c mice were able to control the infection. Furthermore, a dendritic cell-based vaccination against leishmaniasis efficiently suppresses the early secretion of IL-10, thus contributing to the control of parasite spread. Taken together, IL-10 secretion by T cells has an influence on immune activation early after infection and is sufficient to render BALB/c mice susceptible to an uncontrolled Leishmania major infection.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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