TY - JOUR
T1 - Correlates of immune protection in chickens vaccinated with Mycoplasma gallisepticum strain GT5 following challenge with pathogenic M. gallisepticum strain Rlow
AU - Javed, Mohammed A.
AU - Frasca, Salvatore
AU - Rood, Debra
AU - Cecchini, Katharine
AU - Gladd, Martha
AU - Geary, Steven J.
AU - Silbart, Lawrence K.
PY - 2005/9
Y1 - 2005/9
N2 - Colonization of the avian respiratory tract with Mycoplasma gallisepticum results in a profound inflammatory response in the trachea, air sacs, conjunctiva, and lungs. A live attenuated M. gallisepticum vaccine strain, GT5, was previously shown to be protective in chickens upon challenge; however, the mechanisms by which this vaccine and others confer protection remain largely unknown. The current study evaluated several potential correlates of GT5 vaccine-mediated immune protection following challenge with the pathogenic M. gallisepticum strain Rlow. GT5-vaccinated chickens developed mild tracheal lesions, consisting of few and scattered, discrete, lymphofollicular aggregates in the lamina propria. In addition, low numbers of aggregated B, CD4+, and CD8+ cells were observed to infiltrate the trachea, in stark contrast to the large numbers infiltrating the tracheas of sham-vaccinated chickens challenged with Rlow. Lymphofollicular aggregates were rarely observed prior to day 12 postchallenge in sham-vaccinated chickens. Instead, they contained an increasingly more cellular inflammatory response characterized by expansion of the lamina propria by lymphoplasmacytic and histiocytic infiltrates. This was due in part to expansion of interfollicular zones by large numbers of infiltrating CD4+ and CD8+ cells and a sizeable population of immunoglobulin A (IgA)- and IgG-secreting plasma cells. GT5-vaccinated chickens also had higher serum IgG concentrations, and significantly higher numbers of M. gallisepticum-specific IgG- and IgA-secreting plasma/B cells within the trachea, than did sham-vaccinated chickens. These responses were observed as early as day 4 postchallenge, indicating the importance of antibody-mediated clearance of mycoplasma in GT5-vaccinated chickens.
AB - Colonization of the avian respiratory tract with Mycoplasma gallisepticum results in a profound inflammatory response in the trachea, air sacs, conjunctiva, and lungs. A live attenuated M. gallisepticum vaccine strain, GT5, was previously shown to be protective in chickens upon challenge; however, the mechanisms by which this vaccine and others confer protection remain largely unknown. The current study evaluated several potential correlates of GT5 vaccine-mediated immune protection following challenge with the pathogenic M. gallisepticum strain Rlow. GT5-vaccinated chickens developed mild tracheal lesions, consisting of few and scattered, discrete, lymphofollicular aggregates in the lamina propria. In addition, low numbers of aggregated B, CD4+, and CD8+ cells were observed to infiltrate the trachea, in stark contrast to the large numbers infiltrating the tracheas of sham-vaccinated chickens challenged with Rlow. Lymphofollicular aggregates were rarely observed prior to day 12 postchallenge in sham-vaccinated chickens. Instead, they contained an increasingly more cellular inflammatory response characterized by expansion of the lamina propria by lymphoplasmacytic and histiocytic infiltrates. This was due in part to expansion of interfollicular zones by large numbers of infiltrating CD4+ and CD8+ cells and a sizeable population of immunoglobulin A (IgA)- and IgG-secreting plasma cells. GT5-vaccinated chickens also had higher serum IgG concentrations, and significantly higher numbers of M. gallisepticum-specific IgG- and IgA-secreting plasma/B cells within the trachea, than did sham-vaccinated chickens. These responses were observed as early as day 4 postchallenge, indicating the importance of antibody-mediated clearance of mycoplasma in GT5-vaccinated chickens.
UR - http://www.scopus.com/inward/record.url?scp=23944522398&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=23944522398&partnerID=8YFLogxK
U2 - 10.1128/IAI.73.9.5410-5419.2005
DO - 10.1128/IAI.73.9.5410-5419.2005
M3 - Article
C2 - 16113257
AN - SCOPUS:23944522398
SN - 0019-9567
VL - 73
SP - 5410
EP - 5419
JO - Infection and immunity
JF - Infection and immunity
IS - 9
ER -