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Factors in resistance to and recovery from M. pulmonis-induced arthritis in mice
Abstract:
A previous infection of C3H mice with viable Mycoplasma pulmonis organisms protected them from arthritis induced by intravenous inoculation of these organisms, whether or not their initial arthritis had resolved at the time of challenge. Although spleen cells obtained from such animals conferred resistance to acute arthritis in syngeneic recipient mice, convalescent-phase serum was much more effective in this respect. In addition, the transfer of 'immune' spleen cells to M. pulmonis-infected mice treated with cyclophosphamide did not prevent them from dying, whereas the transfer of convalescent-phase serum to such animals reduced the incidence of mortality. Since M. pulmonis organisms are rapidly inactivated in mice treated with convalescent-phase serum it is suggested that the transferred serum may act by promoting phagocytosis of the mycoplasmas. Although the reason for some mice developing a prolonged arthritis is not clear, the results show that humoral immune mechanisms are more important than cell-mediated ones in preventing acute arthritis and that the humoral mechanisms are of greater importance than the cell-mediated in resistance to and recovery from a generalized mycoplasma infection.
Insights
Mice previously infected with Mycoplasma pulmonis resisted arthritis. Humoral immunity, particularly convalescent serum, was more effective than cell-mediated immunity in preventing arthritis and generalized infection.
Area of Science:
- Immunology
- Microbiology
- Veterinary Medicine
Background:
- Mycoplasma pulmonis is a common respiratory pathogen in rodents.
- Arthritis can be induced by Mycoplasma pulmonis infection in mice.
- The roles of humoral and cell-mediated immunity in Mycoplasma pulmonis infection are not fully understood.
Purpose of the Study:
- To investigate the protective effects of previous Mycoplasma pulmonis infection against arthritis.
- To compare the efficacy of cell-mediated and humoral immunity in preventing and resolving Mycoplasma pulmonis-induced arthritis and generalized infection.
Main Methods:
- C3H mice were previously infected with Mycoplasma pulmonis and then challenged with the organism to assess arthritis development.
- Spleen cells and convalescent-phase serum from infected mice were transferred to syngeneic recipient mice.
- Mice treated with cyclophosphamide were used to assess the role of transferred immune components in survival.
Main Results:
- Previous Mycoplasma pulmonis infection conferred protection against arthritis upon challenge.
- Convalescent-phase serum was more effective than spleen cells in conferring resistance to arthritis.
- Transfer of convalescent-phase serum reduced mortality in immunosuppressed infected mice, suggesting a role in pathogen inactivation, possibly via phagocytosis.
Conclusions:
- Humoral immune mechanisms are more critical than cell-mediated mechanisms in preventing acute arthritis caused by Mycoplasma pulmonis.
- Humoral immunity plays a greater role in resistance to and recovery from generalized Mycoplasma pulmonis infection.