Leukotactic factors elaborated by virus-infected tissues

Area of Science:

• Virology
• Immunology
• Cell Biology

Background:

• Viral infections can modulate host immune responses.
• Chemotactic factors attract immune cells to sites of infection.

Purpose of the Study:

• To investigate the source and nature of chemotactic factors produced during viral infections.
• To determine if viral particles or infected cells are responsible for generating these factors.

Main Methods:

• Infection of chick embryos and BGM cell cultures with Newcastle disease virus and mumps virus.
• Analysis of chemotactic activity in infected allantoic fluid and cell culture supernates.
• Ultracentrifugal studies to characterize the distribution of chemotactic activity.

Main Results:

• Infected cells, not viral particles, produced chemotactic activity for neutrophils and macrophages.
• Distinct patterns of chemotactic activity were observed in chick embryos versus cell cultures.
• Virus-infected cells released a substance that generated leukotactic activity upon interaction with complement components C3 or C5.

Conclusions:

• Viral infection induces infected cells to release leukotactic factors.
• The infected cell, rather than the virus, is the primary source of these immune-modulating factors.
• These elaborated leukotactic factors may contribute to host defense during viral infections.