muramidase and Leishmaniasis--Cutaneous

American cutaneous leishmaniasis (ACL) is a chronic infectious disease caused by different protozoan species of Leishmania, and it is endemic in both tropical and subtropical countries. Using immunohistochemistry, we investigate the density of CD68

Topics: Adolescent; Adult; Antigens, CD1; Brazil; CD4 Lymphocyte Count; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Dermis; Disease Progression; Factor XIIIa; Female; Humans; Interferon-gamma; Langerhans Cells; Leishmania; Leishmania braziliensis; Leishmaniasis, Cutaneous; Macrophage Activation; Macrophages; Male; Middle Aged; Muramidase; Young Adult

Leishmaniases are a major international public health problem, and macrophages are crucial for host resistance to this parasite. To determine if phosphatase and tensin homologue deleted on chromosome ten (Pten), a negative regulator of the PI3K pathway, plays a role in macrophage-mediated resistance to Leishmania, we generated C57BL/6 mice lacking Pten specifically in macrophages (LysMCrePten(flox/flox) mice). Examination of lesions resulting from Leishmania major infection showed that LysMCrePten(flox/flox) mice were more susceptible to the parasite than wild-type (WT) mice in the early phase of the infection, but were eventually able to eliminate the pathogen. In vitro Pten-deficient macrophages showed a reduced ability to kill parasites in response to IFN-gamma treatment, possibly because the mutant cells exhibited decreased TNF secretion that correlated with reductions in inducible nitric oxide synthase expression and nitric oxide production. In response to various TLR ligands, Pten-deficient macrophages produced less TNF and IL-12 but more IL-10 than WT cells. However, analysis of cells in the lymph nodes draining L. major inoculation sites indicated that both LysMCrePten(flox/flox) and WT mice developed normal Th1 responses following L. major infection, in line with the ability of LysMCrePten(flox/flox) mice to eventually eliminate the parasite. Our results indicate that the efficient clearance of intracellular parasites requires Pten in macrophages.

Topics: Animals; Arginase; Disease Susceptibility; Gene Deletion; Gene Expression; Integrases; Interferon-gamma; Interleukins; Leishmania major; Leishmaniasis, Cutaneous; Lymph Nodes; Macrophages, Peritoneal; Mice; Mice, Inbred C57BL; Mice, Transgenic; Muramidase; Nitric Oxide Synthase Type II; Nitrites; Phosphatidylinositol 3-Kinases; Phosphatidylinositol Phosphates; PTEN Phosphohydrolase; Toll-Like Receptors; Tumor Necrosis Factor-alpha

Alloreactive T lymphocytes can be primed through direct presentation of donor MHC:peptide complexes on graft cells and through indirect presentation of donor-derived determinants expressed by recipient APCs. The large numbers of determinants on an allograft and the high frequency of the alloreactive repertoire has further led to speculation that exposure to environmental Ags may prime T cells that cross-react with alloantigens. We sought to develop a model in which to test this hypothesis. We found that CD4(+) T cells obtained from C57BL/6 (B6) mice that clinically resolved Leishmania major infection exhibited statistically significant cross-reactivity toward P/J (H-2(p)) Ags compared with the response to other haplotypes. B6 animals that were previously infected with L. major specifically rejected P/J skin grafts with second set kinetics compared with naive animals. Although donor-specific transfusion combined with costimulatory blockade (anti-CD40 ligand Ab) induced prolonged graft survival in naive animals, the same treatment was ineffective in mice previously infected with L. major. The studies demonstrate that cross-reactive priming of alloreactive T cells can occur and provide direct evidence that such T cells can have a significant impact on the outcome of an allograft. The results have important implications for human transplant recipients whose immune repertoires may contain cross-reactively primed allospecific T cells.

Topics: Amino Acid Sequence; Animals; Antigens; Chickens; Cross Reactions; Disease Models, Animal; Female; Graft Rejection; Isoantigens; Leishmania major; Leishmaniasis, Cutaneous; Mice; Mice, Inbred BALB C; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Inbred DBA; Molecular Sequence Data; Muramidase; Ovalbumin; Rabbits; Skin Transplantation; T-Lymphocyte Subsets; Vaccination

Topics: Animals; Antigen Presentation; Antigen-Presenting Cells; Antigens; CD4-Positive T-Lymphocytes; Cell Differentiation; Flow Cytometry; Interferon-gamma; Interleukin-4; Leishmaniasis, Cutaneous; Major Histocompatibility Complex; Mice; Mice, Inbred BALB C; Mice, Inbred Strains; Muramidase; Polymorphism, Genetic; Th1 Cells; Th2 Cells

Continuous administration of soluble protein Ag followed by immunization with the same Ag in adjuvant results in the selective development of Ag-specific CD4+ Th2 cells in both normal and beta2-microglobulin-deficient BALB/c mice. In addition to chronic administration by mini-osmotic pump, single bolus i.p., but not i.v., injection of protein Ag induces Th2 cell expansion. Strong Th2 cell priming depends on a non-MHC-linked genetic polymorphism. It is observed in all congenic strains on BALB background tested, BALB/c, BALB/b, and BALB/k, but not in MHC-matched strains on disparate genetic background, B10.D2, C57BL/6, and C3H. DBA/2 mice appear to have an intermediate phenotype, as shown by their weaker capacity to mount Th2 responses as compared with BALB/c mice after soluble Ag administered by either mini-osmotic pumps or single bolus i.p. Conversely, induction of Th1 cell unresponsiveness by soluble protein is observed in any mouse strain tested, following any mode of Ag administration. These data demonstrate that non-MHC-linked genetic polymorphism controls the priming of Th2 but not the inhibition of Th1 cells induced by administration of soluble protein. The pattern of Th2 responses in these different strains is predictive of disease outcome following Leishmania major infection and supports the hypothesis that systemic Ag presentation in the absence of strong inflammatory signals may represent an important stimulus leading to selective Th2 cell development in susceptible mouse strains.

Topics: Animals; Antigens; beta 2-Microglobulin; Cell Differentiation; Disease Susceptibility; Dose-Response Relationship, Immunologic; Female; Immunity, Cellular; Immunization; Infusion Pumps, Implantable; Injections, Intraperitoneal; Injections, Intravenous; Leishmania major; Leishmaniasis, Cutaneous; Lymphocyte Activation; Mice; Mice, Inbred Strains; Muramidase; Ovalbumin; Phenotype; Polymorphism, Genetic; Species Specificity; Th1 Cells; Th2 Cells; Tuberculin