Component(s) of Sendai virus that can induce interferon in mouse spleen cells

Abstract

To identify the active component of Sendai virus that induces interferon in mouse spleen cells, infectious and noninfectious viruses, envelope particles derived from them, and isolated hemagglutinin-neuraminidase (HN) glycoproteins were examined for interferon induction. The interaction between membranous structures containing Sendai virus HN glycoprotein and the receptors on the cell surface was shown to be sufficient for interferon induction in mouse spleen cells, suggesting that the actual inducer of interferon in mouse spleen cells is the HN glycoprotein of Sendai virus. When mouse spleen cells were stimulated in vitro with Sendai virus grown in eggs or LLC-MK2 cells or with membranous structures containing glycoproteins obtained from these viruses, interferon could be detected in the culture fluid. Furthermore, isolated HN glycoprotein per se could induce interferon in the cells. A linear correlation was found between the titer of interferon induced and the hemagglutinating activity of the membranous structure containing the HN glycoprotein. It was concluded from these findings that HN glycoprotein was the active component of Sendai virus responsible for interferon induction in mouse spleen cells and that viral RNA and F glycoprotein were not required. The results also showed that the interaction between HN glycoprotein and receptors on the cell surface triggered production of type I interferon (IFN-alpha and IFN-beta). Although when Sendai virus was incubated at 56 degrees C for 5 min it lost its hemolytic and hemagglutinating activities, it induced a considerable amount of interferon in the culture fluid of mouse spleen cells. The interferon-inducing ability of heat-inactivated virus could be absorbed with mouse spleen cells but not with sheep erythrocytes or mouse erythrocytes, indicating that the inactivated virus retained ability to bind to mouse lymphoid cells.

More than one component of the Newcastle disease virus particle is capable of interferon induction

“…Replicating and inactivated NDV stimulated IFN production by PBML to the same degree irrespective of strain differences. This is in accordance with results obtained with another IFN stimulation protocol using mouse sPleen cells (Ito et al, 1982, Ito andHosaka, 1983). The same authors describe for mouse L cells, however, that only NDV that replicated in these cells induced an IFN synthesis ( Ito et al, 1982), suggesting that different mechanisms of IFN induction exist in fibroblasts and in lymphoid cells.…”

“…One of these IFN inducers is the NDV HN protein. The same was shown for Sendai virus (Ito and Hosaka, 1983). In addition, we found participation of the F protein precursor, probably the M protein and the isolated genomic RNA in IFN induction.…”

“…For lymphoid cells it has been shown that simply the contact between cell and virion surface is sufficient to induce IFN production, whereas in fibroblasts the virus has to enter the cell (Ito et al, 1982, Ito andHosaka, 1983). To the best of our knowledge there is only one description of Paramyxovirus surface proteins as IFN inducers in lymphoid cells (Ito et al, 1983). The authors found that isolated Sendai virus HN protein is able to stimulate the release of low IFN titres in the supernatant of mouse spleen cells.…”

Induction of interferon by virus glycoprotein(s) in lymphoid cells through interaction with the cellular receptors via lectin-like action: An alternative interferon induction mechanism

“…Even when mouse spleen cells are incubated with membranes containing HN glycoprotein alone, they produce interferon [33]. However, L929 cells have no capacity for interferon production in response to any stimulation of subviral components [33]. It is concluded from these findings that HN glycoprotein is the active component of Sendai virus responsible for interferon induction in mouse spleen cells and that viral RNA and F glycoprotein are not required.…”

“…Furthermore, when mouse spleen cells are incubated with Sendai virus envelope with virus glycoprotein(s) such as HN + F or HN + Fo, interferon-~/13 is induced [33]. Even when mouse spleen cells are incubated with membranes containing HN glycoprotein alone, they produce interferon [33]. However, L929 cells have no capacity for interferon production in response to any stimulation of subviral components [33].…”