Interleukin-1-Inhibitor Activity Induced by Respiratory Syncytial Virus: Abrogation of Virus-Specific and Alternate Human Lymphocyte Proliferative Responses

Abstract

Respiratory syncytial virus (RSV) infection has been shown to induce human mononuclear leukocyte (MNL) production of net interleukin-1 (IL-1)-inhibitor activity. In the current studies of IL-1-inhibitor effects, RSV-exposed cells were compared with autologous MNL that were sham-exposed or exposed to inactivated RSV or influenza virus (which induces net IL-1 activity and commonly elicits effective homotypic immunity). Exposure of MNL to influenza virus or inactivated RSV resulted in increased expression of human leukocyte antigen-DR, the IL-2 receptor, and the transferrin receptor and increased progression through the cell cycle by 3 days. In contrast, exposure to infectious RSV resulted in decreased marker expression and cell cycle arrest, with abrogation of proliferation in response to the virus or other stimuli. These data raise the possibility that a contributing mechanism for recurrence of RSV infection is early suppression of the clonal expansion of virus-specific lymphocytes due to net IL-1-inhibitor activity.

Serum Antibodies Critically Affect Virus-Specific CD4+/CD8+ T Cell Balance during Respiratory Syncytial Virus Infections

“…This finding illustrates the well-documented inhibitory effect of RSV infection on T cell proliferation (28,36,(43)(44)(45)(46). Using expanded virus-specific CD8 + T cell populations, we found similar IFN-g responses induced by HLA class I molecules on both virus-infected APCs and peptideloaded APCs.…”

“…A total of 1 3 10 6 CFSE-labeled PBMCs were stimulated with live RSV (moi 2) or with 1 mg/ml nonstructural protein (NS) [41][42][43][44][45][46][47][48][49] in AIM V (Invitrogen) with 2% IgG-depleted heat-inactivated AS in the presence of 20 U/ml human (h)IL-2 (11147528001, Roche, Basel, Switzerland). After 24 h, cells stimulated with NS [41][42][43][44][45][46][47][48][49] were restimulated with 1 mg/ml peptide/hIL-2. After 7 d, the expanded CD8 + T cells were restimulated with 1 mg/ml peptide or not restimulated in the presence of 1 mg/ml anti-CD28 (340975, BD Biosciences,), 1 mg/ml antiCD49d (BD Biosciences, 340976), 20 U/ml hIL-2 (11147528001, Roche), and 10 mg/ml brefeldin A (B7651, Sigma-Aldrich).…”

“…At day 8 (NS1 [41][42][43][44][45][46][47][48][49] and M2 [64][65][66][67][68][69][70][71][72] ) or at day 9 (N 306-314 ) poststimulation, expanded cells were harvested. NS1 [41][42][43][44][45][46][47][48][49] and M2 [64][65][66][67][68][69][70][71][72] expanded T cells were restimulated with freshly isolated PBMCs from the same donor incubated with RSV (moi 2) in the presence of FCS or AS for 24 h or 1 mg/ml corresponding peptide (NS1 [41][42][43][44][45][46][47][48][49] and M2 64-72 ) as a control for 1 h. N 306-314 -expanded T cells were restimulated with monocytederived immature DCs incubated with RSV, RSV opsonized by 5 mg/ml palivizumab (Synagis, MedImmune) for 48 h, or with 1 mg/ml N 306-314 for 1 h. In both restimulation assays, expanded T cells were added in the presence of 1 mg/ml anti-CD49d (340976, BD Biosciences), 1 mg/ml anti-CD28 (340975, BD Biosciences), 20 U/ml hIL-2 (11147528001, Roche), and 10 mg/ml brefeldin A (Sigma-Aldrich, B7651). After an incubation period of 5 h at 37˚C, intracellular cytokine staining was performed to analyze IFN-g production by CD8…”

“…Fig. 2B shows an example of in vitro T cell expansion poststimulation of PBMCs with peptide NS1 [41][42][43][44][45][46][47][48][49] derived from the nonstructural protein NS1, a peptide that is presented in the context of HLA-B51 (36). More than eight cell divisions were required to detect substantial numbers of IFN-g-producing CD8…”

“…Similar observations were made for epitopes derived from structural proteins (M, Np, M2, data not shown). Expansion of NS1 [41][42][43][44][45][46][47][48][49] specific CD8…”