Expression of chemokine receptor CX₃CR1 in infants with respiratory syncytial virus bronchiolitis

Abstract

Respiratory syncytial virus (RSV) glycoprotein G mimics fractalkine, a CX 3 C chemokine, which mediates chemotaxis of leukocytes expressing its receptor, CX 3 CR1. The aim of this study was to examine the relationship between RSV infection and expression of perforin and IFN- in CX 3 CR1-expressing peripheral blood CD8 + T cells. Samples were collected from infants with RSV bronchiolitis, both in the acute and convalescence phase (n=12), and from their age-and sex-matched healthy controls (n=15). Perforin expression and IFN- secretion in CX 3 CR1 + CD8 + T cells were assessed by four-color flow cytometry. The NF-B p50 and p65 subunit levels were also determined as markers of RSV-induced inflammation. Study results showed perforin and CX 3 CR1 expression to be significantly lower in the convalescent phase of infected infants than in healthy controls. There was no significant difference in IFN- secretion and NF-B binding activity between two time-points in RSV-infected infants, or when compared to healthy controls. Infants with prolonged wheezing had lower acute-phase CX 3 CR1 levels in peripheral blood. These data indicate existence of an event persisting after acute RSV infection that is able to modulate effector functions of cytotoxic T cells, and also link disease severity with CX 3 CR1 expression.

The role of cytokines and chemokines in severe respiratory syncytial virus infection and subsequent asthma

“…Increased levels of chemokines, such as IL-8, MIP1-a/b, eotaxin-1, RANTES and MCP-1 were also observed in bronchoalveolar lavage samples from infants with RSV bronchiolitis [48,57,58]. In agreement with release of chemokines, the levels of their receptor increased after RSV infection, such as CCR1, CCR2, and CCR5 on monocytes [58,59], or decreased in the convalescent phase of RSV infected infants, such as CX3CR1 on CD8 + T cells [60]. CCL3, a chemokine for both T cells and NK cells, is significantly upregulated both during primary murine RSV infection [61] and in enhanced immunopathology after antigenic sensitization [62].…”

Potent High-Affinity Antibodies for Treatment and Prophylaxis of Respiratory Syncytial Virus Derived from B Cells of Infected Patients

“…Consistent with these findings, human polymorphisms showing reduced activity of either TLR4 (27) or CX3CR1 (28) were significantly overrepresented in studies of infants with severe RSV disease.…”

Immunological, Viral, Environmental, and Individual Factors Modulating Lung Immune Response to Respiratory Syncytial Virus

“…The G protein also has reduced homology to fractalkine and can reduce the action of host fractalkine and the influx of natural killer (NK) cells and CD4+ and CD8+ T cells [ 31 ]. The glycoprotein G mimics fractalkine and chemokine involved in the chemotaxis of leukocytes expressing its receptor [ 32 ]. For this reason some authors [ 32 ] hypothesized that RSV modulates effector functions of cytotoxic T cells and that disease severity is linked with CX(3)CR1 expression.…”