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HIV-1 cell to cell transfer across an Env-induced, actin-dependent synapse.

Jolly C, Kashefi K, Hollinshead M, Sattentau QJ - J. Exp. Med. (2004)

Bottom Line: Receptor recognition by HIV-1 occurs via interactions between the viral surface envelope glycoprotein (Env), gp120, and CD4 and a chemokine receptor, CCR5 or CXCR4.Recruitment of these membrane molecules into polarized clusters was dependent on Env engagement of CD4 and CXCR4 and required remodelling of the actin cytoskeleton.We propose that receptor engagement by Env directs the rapid, actin-dependent recruitment of HIV receptors and adhesion molecules to the interface, resulting in a stable adhesive junction across which HIV infects the target cell.

View Article: PubMed Central - PubMed

Affiliation: The Sir William Dunn School of Pathology, University of Oxford, UK.

ABSTRACT
Direct cell-cell transfer is an efficient mechanism of viral dissemination within an infected host, and human immunodeficiency virus 1 (HIV-1) can exploit this mode of spread. Receptor recognition by HIV-1 occurs via interactions between the viral surface envelope glycoprotein (Env), gp120, and CD4 and a chemokine receptor, CCR5 or CXCR4. Here, we demonstrate that the binding of CXCR4-using HIV-1-infected effector T cells to primary CD4(+)/CXCR4(+) target T cells results in rapid recruitment to the interface of CD4, CXCR4, talin, and lymphocyte function-associated antigen 1 on the target cell, and of Env and Gag on the effector cell. Recruitment of these membrane molecules into polarized clusters was dependent on Env engagement of CD4 and CXCR4 and required remodelling of the actin cytoskeleton. Transfer of Gag from effector to target cell was observed by 1 h after conjugate formation, was independent of cell-cell fusion, and was probably mediated by directed virion fusion with the target cell. We propose that receptor engagement by Env directs the rapid, actin-dependent recruitment of HIV receptors and adhesion molecules to the interface, resulting in a stable adhesive junction across which HIV infects the target cell.

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Related in: MedlinePlus

Receptor clustering requires the actin cytoskeleton. (A) Effector target cell conjugates were incubated at 37°C for 1 h in the presence of mAbs for CD4 (red) and Env (green). Conjugates were fixed, permeabilized, and stained for actin (blue). Clusters of f-actin on the target cell are indicated with arrows. (B) Target cells were treated with 1 μM of cytochalasin D (top) or jasplakinolide (bottom) for 1 h at 37°C. Treated cells were washed and incubated with effector cells at 37°C for 1 h with mAbs against CD4 (red) and Env (green).
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fig4: Receptor clustering requires the actin cytoskeleton. (A) Effector target cell conjugates were incubated at 37°C for 1 h in the presence of mAbs for CD4 (red) and Env (green). Conjugates were fixed, permeabilized, and stained for actin (blue). Clusters of f-actin on the target cell are indicated with arrows. (B) Target cells were treated with 1 μM of cytochalasin D (top) or jasplakinolide (bottom) for 1 h at 37°C. Treated cells were washed and incubated with effector cells at 37°C for 1 h with mAbs against CD4 (red) and Env (green).

Mentions: Recruitment of receptors and adhesion molecules into the immunological synapse is an actin-driven process (30). Suspecting that the rapid receptor polarization in our system might, therefore, require cytoskeletal remodeling, we stained conjugates for actin. Actin clustered in the target, but not the effector cell at the interface (Fig. 4 A) and colocalized partially with CD4 and Env. The percentage of conjugates containing polarized actin was significantly higher in the JurkatLAI–target cell conjugates than in the uninfected Jurkat–target conjugates (Table I). Moreover, inhibiting gp120–receptor interactions abolished (Q4210) or reduced (447-52D and AMD3100) actin polarization (Table I). These results imply that actin rearranges within the target cell in an Env-dependent manner.


HIV-1 cell to cell transfer across an Env-induced, actin-dependent synapse.

Jolly C, Kashefi K, Hollinshead M, Sattentau QJ - J. Exp. Med. (2004)

Receptor clustering requires the actin cytoskeleton. (A) Effector target cell conjugates were incubated at 37°C for 1 h in the presence of mAbs for CD4 (red) and Env (green). Conjugates were fixed, permeabilized, and stained for actin (blue). Clusters of f-actin on the target cell are indicated with arrows. (B) Target cells were treated with 1 μM of cytochalasin D (top) or jasplakinolide (bottom) for 1 h at 37°C. Treated cells were washed and incubated with effector cells at 37°C for 1 h with mAbs against CD4 (red) and Env (green).
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Related In: Results  -  Collection

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fig4: Receptor clustering requires the actin cytoskeleton. (A) Effector target cell conjugates were incubated at 37°C for 1 h in the presence of mAbs for CD4 (red) and Env (green). Conjugates were fixed, permeabilized, and stained for actin (blue). Clusters of f-actin on the target cell are indicated with arrows. (B) Target cells were treated with 1 μM of cytochalasin D (top) or jasplakinolide (bottom) for 1 h at 37°C. Treated cells were washed and incubated with effector cells at 37°C for 1 h with mAbs against CD4 (red) and Env (green).
Mentions: Recruitment of receptors and adhesion molecules into the immunological synapse is an actin-driven process (30). Suspecting that the rapid receptor polarization in our system might, therefore, require cytoskeletal remodeling, we stained conjugates for actin. Actin clustered in the target, but not the effector cell at the interface (Fig. 4 A) and colocalized partially with CD4 and Env. The percentage of conjugates containing polarized actin was significantly higher in the JurkatLAI–target cell conjugates than in the uninfected Jurkat–target conjugates (Table I). Moreover, inhibiting gp120–receptor interactions abolished (Q4210) or reduced (447-52D and AMD3100) actin polarization (Table I). These results imply that actin rearranges within the target cell in an Env-dependent manner.

Bottom Line: Receptor recognition by HIV-1 occurs via interactions between the viral surface envelope glycoprotein (Env), gp120, and CD4 and a chemokine receptor, CCR5 or CXCR4.Recruitment of these membrane molecules into polarized clusters was dependent on Env engagement of CD4 and CXCR4 and required remodelling of the actin cytoskeleton.We propose that receptor engagement by Env directs the rapid, actin-dependent recruitment of HIV receptors and adhesion molecules to the interface, resulting in a stable adhesive junction across which HIV infects the target cell.

View Article: PubMed Central - PubMed

Affiliation: The Sir William Dunn School of Pathology, University of Oxford, UK.

ABSTRACT
Direct cell-cell transfer is an efficient mechanism of viral dissemination within an infected host, and human immunodeficiency virus 1 (HIV-1) can exploit this mode of spread. Receptor recognition by HIV-1 occurs via interactions between the viral surface envelope glycoprotein (Env), gp120, and CD4 and a chemokine receptor, CCR5 or CXCR4. Here, we demonstrate that the binding of CXCR4-using HIV-1-infected effector T cells to primary CD4(+)/CXCR4(+) target T cells results in rapid recruitment to the interface of CD4, CXCR4, talin, and lymphocyte function-associated antigen 1 on the target cell, and of Env and Gag on the effector cell. Recruitment of these membrane molecules into polarized clusters was dependent on Env engagement of CD4 and CXCR4 and required remodelling of the actin cytoskeleton. Transfer of Gag from effector to target cell was observed by 1 h after conjugate formation, was independent of cell-cell fusion, and was probably mediated by directed virion fusion with the target cell. We propose that receptor engagement by Env directs the rapid, actin-dependent recruitment of HIV receptors and adhesion molecules to the interface, resulting in a stable adhesive junction across which HIV infects the target cell.

Show MeSH
Related in: MedlinePlus