Correlates of Immune Protection in Chickens Vaccinated with Mycoplasma gallisepticum Strain GT5 following Challenge with Pathogenic M. gallisepticum Strain Rlow

摘要: Colonization of the avian respiratory tract with Mycoplasma gallisepticum results in a profound inflammatory response trachea, air sacs, conjunctiva, and lungs. A live attenuated M. vaccine strain, GT5, was previously shown to be protective chickens upon challenge; however, mechanisms by which this others confer protection remain largely unknown. The current study evaluated several potential correlates GT5 vaccine-mediated immune following challenge pathogenic strain Rlow. GT5-vaccinated developed mild tracheal lesions, consisting few scattered, discrete, lymphofollicular aggregates lamina propria. In addition, low numbers aggregated B, CD4+, CD8+ cells were observed infiltrate stark contrast large infiltrating tracheas sham-vaccinated challenged Lymphofollicular rarely prior day 12 postchallenge chickens. Instead, they contained an increasingly more cellular characterized expansion propria lymphoplasmacytic histiocytic infiltrates. This due part interfollicular zones CD4+ sizeable population immunoglobulin (IgA)- IgG-secreting plasma cells. also had higher serum IgG concentrations, significantly gallisepticum-specific IgG- IgA-secreting plasma/B within than did These responses as early 4 postchallenge, indicating importance antibody-mediated clearance mycoplasma