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Membrane tumor necrosis factor (TNF) induced cooperative signaling of TNFR60 and TNFR80 favors induction of cell death rather than virus production in HIV-infected T cells.

Lazdins JK, Grell M, Walker MR, Woods-Cook K, Scheurich P, Pfizenmaier K - J. Exp. Med. (1997)

Bottom Line: In the present study we have demonstrated by means of antagonistic and agonistic receptor-specific antibodies that in latently infected lymphocytic (ACH-2) cells the TNFR60 plays a dominant role in signaling HIV production, although selective activation of TNFR80 by receptor-specific antibodies can also induce HIV production.Unexpectedly, when both TNFRs were activated simultaneously by agonistic antibodies or coculture with cells expressing a noncleavable membrane form of TNF, HIV production was downregulated and induction of cell death was enhanced in ACH-2 cells.These data provide evidence for the differential trigger potential of membrane versus soluble TNF and show that TNFR80 is an important modulator of TNF responsiveness of HIV-infected T cells via cooperative signaling with TNFR60.

View Article: PubMed Central - PubMed

Affiliation: Division Pharma, Ciba, Basel, Switzerland.

ABSTRACT
Tumor necrosis factor (TNF) and lymphotoxin (LT) are highly pleiotropic cytokines that play a central role in regulating HIV-1 replication. These cytokines express their activities through two membrane receptors, TNFR60 (p55-60) and TNFR80 (p75-80). In the present study we have demonstrated by means of antagonistic and agonistic receptor-specific antibodies that in latently infected lymphocytic (ACH-2) cells the TNFR60 plays a dominant role in signaling HIV production, although selective activation of TNFR80 by receptor-specific antibodies can also induce HIV production. Unexpectedly, when both TNFRs were activated simultaneously by agonistic antibodies or coculture with cells expressing a noncleavable membrane form of TNF, HIV production was downregulated and induction of cell death was enhanced in ACH-2 cells. More relevant, in vitro HIV-infected peripheral blood lymphocytes cocultured with cells expressing membrane TNF underwent rapid induction of apoptosis with a subsequent reduced HIV production of these lymphocytes cultures. This was not observed with HIV-infected lymphocytes treated with soluble TNF. These data provide evidence for the differential trigger potential of membrane versus soluble TNF and show that TNFR80 is an important modulator of TNF responsiveness of HIV-infected T cells via cooperative signaling with TNFR60.

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Coactivation of TNFR60 and TNFR80 downregulates HIV  production and enhances cell death. ACH-2 cells were cultured for 3 d in  the presence of TNF (100 ng/ml) and TNFR-specific antibodies (htr-1,  1/50; M80, 40 μg/ml) as indicated. (A) RT activity (mean values SD of  five replicate cultures) was determined in the supernatants as described in  material and methods. (B) Total cell number of ACH-2 was determined  by the FDA method from the groups shown in A in parallel. Data are expressed as relative cell numbers (100% = untreated cells).
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Figure 4: Coactivation of TNFR60 and TNFR80 downregulates HIV production and enhances cell death. ACH-2 cells were cultured for 3 d in the presence of TNF (100 ng/ml) and TNFR-specific antibodies (htr-1, 1/50; M80, 40 μg/ml) as indicated. (A) RT activity (mean values SD of five replicate cultures) was determined in the supernatants as described in material and methods. (B) Total cell number of ACH-2 was determined by the FDA method from the groups shown in A in parallel. Data are expressed as relative cell numbers (100% = untreated cells).

Mentions: To further scrutinize the individual role of the two TNFRs in induction of HIV, we used agonistic monoclonal (htr-1, MR2-1) and polyclonal (M80) antibodies against TNFR60 and TNFR80 to substitute for TNF in this response. Stimulation with the TNFR60 agonist htr-1 induced a strong response similar to saturating concentrations of TNF (Fig. 3), indicating that selective TNFR60 triggering is sufficient to induce maximum TNF responses with respect to RT activation. However, selective TNFR80 triggering by either polyclonal (M80) (Figs. 3 A and 4 A) or monoclonal (MR2-1; Fig. 3 B) receptor-specific antibodies induced significant RT activity in ACH-2 cells, too, reaching 35–50% of the maximum response induced by TNF or htr-1 stimulation (Figs. 3 and 4 A). Specificity was controlled by the use of mono- and polyclonal antibodies directed against the huIFNγ receptor, which exerted no HIV-inducing activity (56 and 59 cpm, respectively, versus a background value of 66 cpm). Accordingly, TNFR80 is also linked to signal pathways leading to HIV replication.


Membrane tumor necrosis factor (TNF) induced cooperative signaling of TNFR60 and TNFR80 favors induction of cell death rather than virus production in HIV-infected T cells.

Lazdins JK, Grell M, Walker MR, Woods-Cook K, Scheurich P, Pfizenmaier K - J. Exp. Med. (1997)

Coactivation of TNFR60 and TNFR80 downregulates HIV  production and enhances cell death. ACH-2 cells were cultured for 3 d in  the presence of TNF (100 ng/ml) and TNFR-specific antibodies (htr-1,  1/50; M80, 40 μg/ml) as indicated. (A) RT activity (mean values SD of  five replicate cultures) was determined in the supernatants as described in  material and methods. (B) Total cell number of ACH-2 was determined  by the FDA method from the groups shown in A in parallel. Data are expressed as relative cell numbers (100% = untreated cells).
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Related In: Results  -  Collection

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Figure 4: Coactivation of TNFR60 and TNFR80 downregulates HIV production and enhances cell death. ACH-2 cells were cultured for 3 d in the presence of TNF (100 ng/ml) and TNFR-specific antibodies (htr-1, 1/50; M80, 40 μg/ml) as indicated. (A) RT activity (mean values SD of five replicate cultures) was determined in the supernatants as described in material and methods. (B) Total cell number of ACH-2 was determined by the FDA method from the groups shown in A in parallel. Data are expressed as relative cell numbers (100% = untreated cells).
Mentions: To further scrutinize the individual role of the two TNFRs in induction of HIV, we used agonistic monoclonal (htr-1, MR2-1) and polyclonal (M80) antibodies against TNFR60 and TNFR80 to substitute for TNF in this response. Stimulation with the TNFR60 agonist htr-1 induced a strong response similar to saturating concentrations of TNF (Fig. 3), indicating that selective TNFR60 triggering is sufficient to induce maximum TNF responses with respect to RT activation. However, selective TNFR80 triggering by either polyclonal (M80) (Figs. 3 A and 4 A) or monoclonal (MR2-1; Fig. 3 B) receptor-specific antibodies induced significant RT activity in ACH-2 cells, too, reaching 35–50% of the maximum response induced by TNF or htr-1 stimulation (Figs. 3 and 4 A). Specificity was controlled by the use of mono- and polyclonal antibodies directed against the huIFNγ receptor, which exerted no HIV-inducing activity (56 and 59 cpm, respectively, versus a background value of 66 cpm). Accordingly, TNFR80 is also linked to signal pathways leading to HIV replication.

Bottom Line: In the present study we have demonstrated by means of antagonistic and agonistic receptor-specific antibodies that in latently infected lymphocytic (ACH-2) cells the TNFR60 plays a dominant role in signaling HIV production, although selective activation of TNFR80 by receptor-specific antibodies can also induce HIV production.Unexpectedly, when both TNFRs were activated simultaneously by agonistic antibodies or coculture with cells expressing a noncleavable membrane form of TNF, HIV production was downregulated and induction of cell death was enhanced in ACH-2 cells.These data provide evidence for the differential trigger potential of membrane versus soluble TNF and show that TNFR80 is an important modulator of TNF responsiveness of HIV-infected T cells via cooperative signaling with TNFR60.

View Article: PubMed Central - PubMed

Affiliation: Division Pharma, Ciba, Basel, Switzerland.

ABSTRACT
Tumor necrosis factor (TNF) and lymphotoxin (LT) are highly pleiotropic cytokines that play a central role in regulating HIV-1 replication. These cytokines express their activities through two membrane receptors, TNFR60 (p55-60) and TNFR80 (p75-80). In the present study we have demonstrated by means of antagonistic and agonistic receptor-specific antibodies that in latently infected lymphocytic (ACH-2) cells the TNFR60 plays a dominant role in signaling HIV production, although selective activation of TNFR80 by receptor-specific antibodies can also induce HIV production. Unexpectedly, when both TNFRs were activated simultaneously by agonistic antibodies or coculture with cells expressing a noncleavable membrane form of TNF, HIV production was downregulated and induction of cell death was enhanced in ACH-2 cells. More relevant, in vitro HIV-infected peripheral blood lymphocytes cocultured with cells expressing membrane TNF underwent rapid induction of apoptosis with a subsequent reduced HIV production of these lymphocytes cultures. This was not observed with HIV-infected lymphocytes treated with soluble TNF. These data provide evidence for the differential trigger potential of membrane versus soluble TNF and show that TNFR80 is an important modulator of TNF responsiveness of HIV-infected T cells via cooperative signaling with TNFR60.

Show MeSH
Related in: MedlinePlus