Effect of passively administered immunoglobulin G on the colonization and clearance of Bordetella avium in turkeys

This study was conducted to detect the effect of parenterally administered immunoglobulin isotype G (IgG) on the colonization and clearance of Bordetella avium at the tracheal surface in young turkeys. In two separate experiments, 3-week-old turkeys were infected with B. avium either after or before IgG administration. Comparisons were made between a control group which received an irrelevant IgG (specific for keyhole limpet hemocyanin [KLH]) and the experimental group which received a B. avium-specific IgG. When given before the bacteria, IgG reduced the numbers of colony-forming units (CFUs) in the trachea. As a supplement to non-specific respiratory defense mechanisms, B. avium-specific IgG also appears to inhibit colonization of the tracheal mucosa. In a second experiment designed to study the role of IgG in bacterial clearance, administration of B. avium-specific IgG after bacterial inoculation significantly reduced the number of CFUs on the tracheal surface. These studies support the role of B. avium-specific IgG in resistance to and recovery from B. avium infection.