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Specific uptake of tumor necrosis factor-alpha is involved in growth control of Trypanosoma brucei.

Magez S, Geuskens M, Beschin A, del Favero H, Verschueren H, Lucas R, Pays E, de Baetselier P - J. Cell Biol. (1997)

Bottom Line: The specific uptake of the cytokine by the parasite results in a developmentally regulated loss of osmoregulatory capacity.Anti-TNF-alpha treatment of T. brucei-infected mice reveals a dramatic increase in parasitaemia in the blood circulation, the spleen, the lymph nodes, and the peritoneal cavity.These data suggest that in the mammalian host, TNF-alpha is involved in the growth control of T. brucei.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Cellular Immunology, Flanders Interuniversity Institute for Biotechnology, Vrije Universiteit Brussel, Belgium.

ABSTRACT
Trypanosoma brucei is lysed by tumor necrosis factor-alpha (TNF-alpha) in a dose-dependent way, involving specific binding of the cytokine to a trypanosomal glycoprotein present in the flagellar pocket of the parasite. TNF-alpha-gold particles are endocytosed via coated pits and vesicles and are directed towards lysosome-like digestive organelles. The specific uptake of the cytokine by the parasite results in a developmentally regulated loss of osmoregulatory capacity. TNF-alpha specific lysis is prevented when lysis assays are performed at a temperature <26 degrees C, despite uptake of the cytokine. Inhibition of lysis is also observed when a lysosomotropic agent is added during the first 2 h of incubation. Both monomorphic and pleomorphic trypanosomes are lysed but only when isolated during the peak of parasitaemia. Lysis is not observed with early infection stage parasites or procyclic (insect-specific) forms. Anti-TNF-alpha treatment of T. brucei-infected mice reveals a dramatic increase in parasitaemia in the blood circulation, the spleen, the lymph nodes, and the peritoneal cavity. These data suggest that in the mammalian host, TNF-alpha is involved in the growth control of T. brucei.

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Specific inhibition of TNF-α–mediated lysis  of bloodstream forms of T.  brucei by anti-TIP antibodies. (a) Freshly isolated  bloodstream-form trypanosomes were incubated for up  to 8 h in PSG (pH 8.0) at  30°C in the presence of different concentrations of  TNF-α. Trypanolysis was calculated as described in Materials and Methods (▪). Lysis  was inhibited by preincubation of TNF-α with three different TIP-specific antibodies. The polyclonal antibody  (□) as well as both monoclonal antibodies 1E12 (•)  and 24C11 (○), all inhibited  the TNF-α–specific trypanolysis to approximately the same extent. (b) None of the anti-TIP  antibodies inhibited TNF-α–mediated lysis of the TNF-α–sensitive L929 cell line. The same symbols are used as in panel (a).
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Figure 12: Specific inhibition of TNF-α–mediated lysis of bloodstream forms of T. brucei by anti-TIP antibodies. (a) Freshly isolated bloodstream-form trypanosomes were incubated for up to 8 h in PSG (pH 8.0) at 30°C in the presence of different concentrations of TNF-α. Trypanolysis was calculated as described in Materials and Methods (▪). Lysis was inhibited by preincubation of TNF-α with three different TIP-specific antibodies. The polyclonal antibody (□) as well as both monoclonal antibodies 1E12 (•) and 24C11 (○), all inhibited the TNF-α–specific trypanolysis to approximately the same extent. (b) None of the anti-TIP antibodies inhibited TNF-α–mediated lysis of the TNF-α–sensitive L929 cell line. The same symbols are used as in panel (a).

Mentions: To confirm the involvement of the previously described lectin-like TNF/TIP domain in TNF-α–mediated trypanolysis (25), new monoclonal anti-TNF/TIP antibodies were elicited against TNF/TIP peptides encompassing the lectin-like activity of TNF-α. Antibodies were initially selected based on their affinity in ELISA for the TIP peptides used for immunization. For the selected monoclonal antibodies 1E12 and 24C11, the affinity for native TNF-α was further checked using the biosensor technique previously used to measure the affinity between trypanosome lysate and TNF-α. The dissociation constant values recorded were 32.7 ± 4.1 nM and 160.4 ± 67.9 nM for 1E12 and 24C11, respectively. As shown in Fig. 12, both antibodies and a previously described polyclonal rabbit anti-TIP antibody (25) were capable of neutralizing the trypanolytic effect of TNF-α in vitro (Fig. 12 a), while no inhibition activity was observed in a classical L929 TNF-α tumor lysis assay (Fig. 12 b).


Specific uptake of tumor necrosis factor-alpha is involved in growth control of Trypanosoma brucei.

Magez S, Geuskens M, Beschin A, del Favero H, Verschueren H, Lucas R, Pays E, de Baetselier P - J. Cell Biol. (1997)

Specific inhibition of TNF-α–mediated lysis  of bloodstream forms of T.  brucei by anti-TIP antibodies. (a) Freshly isolated  bloodstream-form trypanosomes were incubated for up  to 8 h in PSG (pH 8.0) at  30°C in the presence of different concentrations of  TNF-α. Trypanolysis was calculated as described in Materials and Methods (▪). Lysis  was inhibited by preincubation of TNF-α with three different TIP-specific antibodies. The polyclonal antibody  (□) as well as both monoclonal antibodies 1E12 (•)  and 24C11 (○), all inhibited  the TNF-α–specific trypanolysis to approximately the same extent. (b) None of the anti-TIP  antibodies inhibited TNF-α–mediated lysis of the TNF-α–sensitive L929 cell line. The same symbols are used as in panel (a).
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Related In: Results  -  Collection

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Figure 12: Specific inhibition of TNF-α–mediated lysis of bloodstream forms of T. brucei by anti-TIP antibodies. (a) Freshly isolated bloodstream-form trypanosomes were incubated for up to 8 h in PSG (pH 8.0) at 30°C in the presence of different concentrations of TNF-α. Trypanolysis was calculated as described in Materials and Methods (▪). Lysis was inhibited by preincubation of TNF-α with three different TIP-specific antibodies. The polyclonal antibody (□) as well as both monoclonal antibodies 1E12 (•) and 24C11 (○), all inhibited the TNF-α–specific trypanolysis to approximately the same extent. (b) None of the anti-TIP antibodies inhibited TNF-α–mediated lysis of the TNF-α–sensitive L929 cell line. The same symbols are used as in panel (a).
Mentions: To confirm the involvement of the previously described lectin-like TNF/TIP domain in TNF-α–mediated trypanolysis (25), new monoclonal anti-TNF/TIP antibodies were elicited against TNF/TIP peptides encompassing the lectin-like activity of TNF-α. Antibodies were initially selected based on their affinity in ELISA for the TIP peptides used for immunization. For the selected monoclonal antibodies 1E12 and 24C11, the affinity for native TNF-α was further checked using the biosensor technique previously used to measure the affinity between trypanosome lysate and TNF-α. The dissociation constant values recorded were 32.7 ± 4.1 nM and 160.4 ± 67.9 nM for 1E12 and 24C11, respectively. As shown in Fig. 12, both antibodies and a previously described polyclonal rabbit anti-TIP antibody (25) were capable of neutralizing the trypanolytic effect of TNF-α in vitro (Fig. 12 a), while no inhibition activity was observed in a classical L929 TNF-α tumor lysis assay (Fig. 12 b).

Bottom Line: The specific uptake of the cytokine by the parasite results in a developmentally regulated loss of osmoregulatory capacity.Anti-TNF-alpha treatment of T. brucei-infected mice reveals a dramatic increase in parasitaemia in the blood circulation, the spleen, the lymph nodes, and the peritoneal cavity.These data suggest that in the mammalian host, TNF-alpha is involved in the growth control of T. brucei.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Cellular Immunology, Flanders Interuniversity Institute for Biotechnology, Vrije Universiteit Brussel, Belgium.

ABSTRACT
Trypanosoma brucei is lysed by tumor necrosis factor-alpha (TNF-alpha) in a dose-dependent way, involving specific binding of the cytokine to a trypanosomal glycoprotein present in the flagellar pocket of the parasite. TNF-alpha-gold particles are endocytosed via coated pits and vesicles and are directed towards lysosome-like digestive organelles. The specific uptake of the cytokine by the parasite results in a developmentally regulated loss of osmoregulatory capacity. TNF-alpha specific lysis is prevented when lysis assays are performed at a temperature <26 degrees C, despite uptake of the cytokine. Inhibition of lysis is also observed when a lysosomotropic agent is added during the first 2 h of incubation. Both monomorphic and pleomorphic trypanosomes are lysed but only when isolated during the peak of parasitaemia. Lysis is not observed with early infection stage parasites or procyclic (insect-specific) forms. Anti-TNF-alpha treatment of T. brucei-infected mice reveals a dramatic increase in parasitaemia in the blood circulation, the spleen, the lymph nodes, and the peritoneal cavity. These data suggest that in the mammalian host, TNF-alpha is involved in the growth control of T. brucei.

Show MeSH
Related in: MedlinePlus