Mice with homologous disruption of the gene coding for either p35 subunit or p40 interleukin-12 (IL-12) and derived from a strain genetically resistant to infection Leishmania major have been used study further role this cytokine in resistance differentiation functional CD4+ T cell subsets vivo. Wild-type 129/Sv/Ev mice are L. showing only small lesions which resolve spontaneously within few weeks develop type 1 response. In contrast, lacking bioactive IL-12 (IL-12p35-/- IL-12p40-/-)...

The possible immunomodulatory role of polymorphonuclear leukocytes (PMN) in CD4+ T lymphocyte differentiation mice was examined by studying the effect transient depletion PMN during early phase after Leishmania major delivery. A single injection PMN-depleting NIMP-R14 mAb 6 h before infection with L. prevented burst IL-4 mRNA transcription otherwise occurring draining lymph node susceptible BALB/c mice. Since this transcripts had previously been shown to instruct Th2 from strain, we on Th...

Mice with homologous disruption of the gene coding for ligand-binding chain interferon (IFN) gamma receptor and derived from a strain genetically resistant to infection Leishmania major have been used study further role this cytokine in differentiation functional CD4+ T cell subsets vivo resistance infection. Wild-type 129/Sv/Ev mice are parasite, developing only small lesions, which resolve spontaneously within 6 wk. In contrast, lacking IFN-gamma develop large, progressing lesions. After...

The effect of in vivo treatment with anti-L3T4 monoclonal antibody (mAb) on the course experimentally-induced cutaneous leishmaniasis was studied genetically susceptible BALB/c mice. Administration mAb resulted a pronounced therapeutic as reflected by both resolution lesions and dramatic reduction parasite load treated This specific for correlated selective depletion L3T4+ T cells lymphoid tissues Moreover, concurrent mice were dependent upon isotype employed.

Abstract Recent evidence indicates that B cells are required for susceptibility to infection with Leishmania major in BALB/c mice. In this study, we analyzed the role of IL-10 produced by process. We showed purified from spleen mice response stimulation L. vitro. vivo, early mRNA expression is detected after draining lymph nodes susceptible BALB/c, but not resistant C57BL/6 Although adoptive transfer naive wild-type prior cell-deficient restored Th2 cell development and these otherwise mice,...

Abstract Susceptibility of BALB/c mice to infection with Leishmania major is associated a T helper type 2 (Th2) response. Since interleukin‐4 (IL‐4) critically required early for Th2 cell development, the kinetics IL‐4 mRNA expression was compared in susceptible and resistant during first days infection. In contrast mice, exhibited peak their spleens 90 min after i.v. injection parasites lymph nodes 16 h s.c. injection. IL‐12 interferon‐γ (IFN‐γ) down‐regulated this mRNA; effect IFN‐γ...

Abstract Susceptibility and development of Th2 cells in BALB/c mice infected with Leishmania major result from early IL-4 production by Vβ4Vα8 CD4+ T response to the homolog mammalian RACK1 Ag. A role for CD4+CD25+ regulatory control this was investigated depleting vivo cell population. Depletion induced an increase burst mRNA draining lymph nodes mice, exacerbated course disease higher levels protein their nodes. We further showed that transfer 107 spleen were depleted rendered SCID...

The effect of adoptive transfer in vitro-propagated Leishmania major-specific T cell populations on the course experimentally induced cutaneous leishmaniasis was studied mice. L. cells expressed helper/inducer phenotype and were able vitro to a) mount a specific proliferative response, b) provide helper activity for antibody responses, c) activate parasitized macrophages resulting major destruction, d) secrete macrophage-activating factors as tested tumoricidal assay. These also found...

Previous results have documented a burst of IL-4 mRNA that peaks in draining lymph nodes susceptible BALB/c mice 16 h after infection with Leishmania major. The importance this early response subsequent Th2 cell maturation is supported by observations showing 1) neutralization at the initiation or 2) administration IL-12, which an inhibition burst, inhibits development. However, both treatments are effective hampering development only if given time when has been produced for <48 h. At...

Abstract We have previously shown that the priming of mice with live Mycobacterium tuberculosis var. bovis (Bacillus Calmette‐Guérin, BCG) and immunization repetitive malaria synthetic peptide (NANP) 40 conjugated to purified protein derivative (PPD), led induction high long‐lasting titers anti‐peptide IgG antibodies, overcoming requirement adjuvants genetic restriction antibody response (Lussow et al., Proc. Natl. Acad. Sci. USA 1990. 87: 2960). This initial work us following observations....

CD8+ T cells have been shown to contribute the rapid resolution of secondary lesions developing in immune mice challenged with Leishmania major. In present study, we assessed directly participation specific memory response induced by reinfection. Lymphocyte populations from reinfected exhibit marked gamma interferon (IFN-gamma) responses. The IFN-gamma-producing elicited infectious challenge was demonstrated both genetically resistant CBA and susceptible BALB/c that were rendered...

The cellular basis of neonatally induced T cell tolerance has been investigated in a model system which usage particular TCR V beta segment (V 6) is strongly correlated with reactivity to antigens encoded by the Mlsa genetic locus. Expression 6 peripheral cells was virtually abolished BALB/c (H-2d, Mlsb) mice rendered tolerant DBA/2 Mlsa) lymphoid cells, whereas control 8-bearing remained at near normal levels. Further analysis revealed that elimination 6+ occurred thymus and could not be...

The involvement of Lyt-2+ T cells in the immunological control cutaneous leishmaniasis was assessed by studying course disease mice which number these reduced treatment with anti-Lyt-2 monoclonal antibody (mAb). Administration mAb exacerbated Leishmania major-induced lesions both genetically resistant and susceptible mice. This effect correlated a drastic reduction specific generated during infection. These results, together observation that possess higher numbers lymph nodes draining their...

Studies were performed to define the cellular parameters involved in interference with induction of immunologic unresponsiveness human gamma globulin (HGG) by bacterial lipopolysaccharide (LPS). Mice which injected deaggregated HGG (tolerogen) and LPS did not become tolerant that antigen, but rather became primed a subsequent challenge immunogen. The ability prime tolerogen was also demonstrated an adoptive transfer system. temporal relationship between injection critical for priming occur....

Abstract In vivo induction of autoantibodies by polyclonal B cell activators has been suggested to be the direct consequence lymphocyte activation. Since appearance various represents a common feature some parasitic infections, possibility that such develop as result stimulation antibody synthesis was tested in mice infected experimentally with Trypanosoma brucei (T. brucei). Polyclonal production spleen measured Cunningham plaque-forming (PFC) assay SRBC, TNP-SRBC, and FITC-SRBC indicator...

The role of the IgE-FcεRI complex in malaria severity Plasmodium falciparum-hosting patients is unknown. We demonstrate that mice genetically deficient for high-affinity receptor IgE (FcεRIα-KO) or (IgE-KO) are less susceptible to experimental cerebral (ECM) after infection with berghei (PbANKA). Mast cells and basophils, which classical IgE-expressing effector cells, not involved disease as mast cell-deficient basophil-depleted developed a similar wild-type mice. However, we show emergence...