Immunological analysis and pathological examination of gnotobiotic mice monoassociated with Mycoplasma pneumoniae

Abstract

Although mycoplasmal pneumonia has been generally considered to be a disease with good prognosis, a pathogenic host immune response has been associated with its occurrence. In the present study, the pathogenic significance of the immune response was examined using germfree mice either infected intranasally with Mycoplasma pneumoniae or inoculated with M. pneumoniae antigens (soluble antigen and partially purified antigen). In gnotobiotic mice monoassociated with M. pneumoniae, 10 4 c.f.u. M. pneumoniae per lung were isolated 2-28 days after infection. Inflammatory changes with infiltration of lymphocytes were histopathologically detected in the perivascular area at 2 and 7 days after infection. In the mice intranasally inoculated with soluble antigen or partially purified antigens (F6 and F10 antigens), infiltration of neutrophils and lymphocytes was histopathologically detected at 2 days after inoculation. Severe pneumonia with tissue destruction was observed in the mice inoculated with F6 antigen. A gamma interferon (IFN-c) dominant response in endogenous cytokine expression was observed in all the treated mice. These results indicate that inflammatory changes in the lung tissue were prolonged in gnotobiotic mice monoassociated with M. pneumoniae compared with mice inoculated with M. pneumoniae antigen. In addition, it was shown that IFN-c plays an important role in the pathogenesis of pneumonia in mice either infected with M. pneumoniae or inoculated with its antigen. In particular, the F6 antigen has been considered to be an important virulence factor in terms of induction of tissue injury causing infiltration of lymphocytes and neutrophils in the lung, suggesting a close interaction between the immune response and the occurrence of M. pneumoniae pneumonia.

Clinical and laboratory profiles of refractory Mycoplasma pneumoniae pneumonia in children

“…Pulmonary injury associated with severe or refractory M. pneumoniae pneumonia may be due to the host's immune response rather than to direct microbial damage. 3,13,16,20,21 Most of the recently published studies have been case reports and the characteristics of RMPP have not been comprehensively expounded.…”

Role IL-17A and IL-10 in the antigen induced inflammation model by Mycoplasma pneumoniae

“…M. pneumoniae soluble antigens were prepared as previously described [20,21]. The cultured bacteria were harvested and washed 5 times by centrifugation at 10000 × g for 20 min ( M. pneumoniae ) or 3000 × g for 15 min ( K. pneumoniae and S. pneumoniae ) in Hanks’ balanced salt solution (Gibco, New York, USA).…”

“…We have previously reported that experimental pneumonia can be caused by intranasal inoculation of M. pneumoniae soluble sonicated antigens to specific pathogen-free (SPF) mice [20,21]. In the present study, we prepared a M. pneumoniae antigen induced inflammation model by use of SPF mice recurrently inoculated with M. pneumoniae antigens and performed pathological and immunological analyses to examine the induction mechanisms of Th17 and Treg cells.…”

A 7-year-old girl with subcutaneous emphysema, pneumomediastinum, pneumothorax, and pneumoretroperitoneum caused by Mycoplasma pneumoniae pneumonia

“…Serum ferritin levels are generally high in cases of hemophagocytic syndrome with hypercytokinemia [12]. In addition, the patient's extraordinarily high M. pneumoniae titer levels could be related to the degree of virulence [13]. Although methylprednisolone pulse therapy is an effective treatment for hemophagocytic syndrome due to severe M. pneumoniae pneumonia [1], we gave our patient prednisolone 2 mg/kg/ day and macrolides (or minocycline).…”