Serum-Dependent Enhancement of Coxsackievirus B4-Induced Production of IFNα, IL-6 and TNFα by Peripheral Blood Mononuclear Cells

Increased levels of IFN-α have been found in patients with type 1 diabetes who have detectable levels of coxsackievirus B4 (CVB4) RNA in their blood. The IFN-α-inducing activity of CVB4 in vitro is weak but can be enhanced by human IgGs. Therefore, it was investigated in vitro whether a preferential IFN-α response of peripheral blood mononuclear cells (PBMCs) to CVB4 exists in patients with type 1 diabetes (n=56) compared with healthy subjects (n=20) and whether antibodies play a role. In patients, the levels of IFN-α obtained after stimulation by PBMCs with CVB4 were higher (P=0·008), an individual IFN-α response by PBMCs to CVB4 was more frequent (P=0·0004) and increased levels of IFN-α were observed in CVB4-infected whole blood cultures. The IFN-α-inducing activity of patients plasma and IgGs mixed with CVB4 and then added to PBMCs was high in comparison with healthy subjects (P<0·001) and was inhibited by preincubating the cells with anti-FcγRII, anti-FcγRIII and anti-CAR (coxsackievirus and adenovirus receptor) antibodies. The strong IFN-α responsiveness of PBMCs to CVB4 suggested that IgGs bound to the cell surface might play a role. A short 56 °C incubation of PBMCs from patients responsive to CVB4 generated supernatants, which, when added to cells, exhibited IFN-α-enhancing activity in combination with CVB4, whereas those of controls did not. Specific antibodies for FcγRI, FcγRII and CAR inhibited this activity. These studies demonstrate that CVB4, through interactions with circulating and/or cell-bound IgGs, can strongly induce the production of IFN-α by PBMCs from patients with type 1 diabetes.

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Human antibodies isolated from plasma by affinity chromatography increase the coxsackievirus B4-induced synthesis of interferon-α by human peripheral blood mononuclear cells in vitro

Journal of General Virology ◽

10.1099/0022-1317-82-8-1899 ◽

2001 ◽

Vol 82 (8) ◽

pp. 1899-1907 ◽

Cited By ~ 35

Author(s):

Wassim Chehadeh ◽

Ahmed Bouzidi ◽

Gunar Alm ◽

Pierre Wattré ◽

Didier Hober

Keyword(s):

Peripheral Blood Mononuclear Cells ◽

Peripheral Blood ◽

Mononuclear Cells ◽

Human Peripheral Blood ◽

Interferon Α ◽

Peripheral Blood Mononuclear ◽

Coxsackievirus B4 ◽

Healthy Donors ◽

Blood Mononuclear Cells

Coxsackievirus B4 (CVB4) can be found in circulating blood of patients; however, the interaction of CVB4 with peripheral blood mononuclear cells (PBMCs) is poorly understood. CVB4 induced low levels of IFN-α synthesis in PBMCs from healthy donors. In contrast, preincubation of infectious CVB4 with plasma from these donors containing anti-CVB4 antibodies strongly enhanced the synthesis of IFN-α. IgG obtained from plasma by chromatography formed immune complexes with CVB4 and increased significantly the CVB4-induced production of IFN-α by PBMCs. These antibodies did not have a neutralizing effect on CVB4 infection of Hep-2 cells. The role of CVB and adenovirus receptor (CAR), FcγRII and FcγRIII in the increased synthesis of IFN-α induced by CVB4 preincubated with IgG was shown by inhibition with specific antibodies. The major interferon-α-producing cells in response to CVB4–IgG complexes were CD14+ cells and monocyte-enriched PBMCs. With the latter, detection of IFN-α by immunostaining was positive whereas in monocyte-depleted PBMCs it was not. This study shows that CVB4-induced synthesis of IFN-α by PBMCs can be enhanced by an antibody-dependent mechanism through interactions between the virus, non-neutralizing antivirus antibodies, FcγRII and III and CAR.

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