Ureaplasma diversum clearance in lung mice infection is mediated by neutrophils

Pneumonia in cattle is one of the causes of morbidity rates and economic loss. The host response to lung infections caused by Ureaplasma diversum in bovines is virtually unknown. Here in the immune response was evaluated in a murine model for an experimental pulmonary infection by U. diversum. Therefore, AJ, BALB/C and C57BL/6 mice received intratracheal inoculation of U. diversum and were evaluated after 1, 2, 3, 7 and 14 days and the clinical specimens were collected. In bronchoalveolar lavages (BAL) an increase of inflammatory cells was observed. Neutrophils were the main cells recruited to the site of infection and the infiltration was coincided with the production of pro-inflammatory cytokines. We found a large amount of neutrophil in this initial period, followed by a decrease 7 and 14 days post infection, accompanied by bacterial clearance. Our results evidenced the presence of U. diversum within the neutrophil that suggests a phagocytic role of this cell in the elimination of the infection. The immune response features reported here are the initial evidence that healthy immune systems may control these microorganisms. This may be the first step to design new strategies immune based to control the infections in naturally infected hosts.