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Mouse footpad infection by Pseudomonas aeruginosa: evidence for delayed hypersensitivity to specific bacterial
Abstract:
Mouse hind footpad inoculation with 1 x 10(7) viable Pseudomonas aeruginosa cells produces a long-lasting, self-limiting disease process characterized by a bacterial multiplication that parallels the swelling of the infected footpad. Regional popliteal and inguinal lymph nodes and spleen of infected animals show cellular modifications which are almost entirely due to lymphocyte proliferation, as indicated by sponteneous DNA synthesis experiments in vitro. Furthermore, mice which had been infected in their footpad either 20 or 27 days previously and challenged with P. aeruginosa antigens into the controlateral footpad show, 24 h later, a marked increase in regional popliteal lymph node weight, indicating the development of delayed hypersensitivity to Pseudomonas antigens.
Insights
Pseudomonas aeruginosa infection in mice causes a self-limiting disease with bacterial growth correlating to footpad swelling. This study demonstrates the development of delayed hypersensitivity to Pseudomonas antigens in infected mice.
Area of Science:
- Immunology
- Microbiology
- Infectious Diseases
Background:
- Pseudomonas aeruginosa is an opportunistic pathogen causing various infections.
- Understanding the host immune response to P. aeruginosa is crucial for developing effective treatments.
Purpose of the Study:
- To characterize the immune response to a self-limiting Pseudomonas aeruginosa infection in a mouse model.
- To investigate the development of delayed hypersensitivity to P. aeruginosa antigens.
Main Methods:
- Mouse hind footpad inoculation with Pseudomonas aeruginosa.
- Monitoring bacterial load and footpad swelling.
- Assessing cellular modifications in lymph nodes and spleen via in vitro DNA synthesis.
- Evaluating delayed hypersensitivity response through secondary antigen challenge.
Main Results:
- A long-lasting, self-limiting disease characterized by bacterial multiplication and footpad swelling was observed.
- Lymphocyte proliferation was the primary cellular modification in regional lymph nodes and spleen.
- Mice previously infected with P. aeruginosa exhibited a heightened regional lymph node response upon secondary antigen challenge, indicating delayed hypersensitivity.
Conclusions:
- The mouse footpad model effectively mimics a self-limiting P. aeruginosa infection.
- The adaptive immune system, particularly lymphocyte proliferation, plays a key role in resolving the infection.
- Delayed hypersensitivity develops in response to Pseudomonas antigens, suggesting a role for cell-mediated immunity in protection.