Plasmodium yoelii: cellular immune responses in splenectomized and normal mice

Area of Science:

• Immunology
• Infectious Diseases
• Malariology

Background:

• Plasmodium yoelii 17X infection impacts different mouse strains variably.
• C57BL/6 (B6) mice are susceptible, while DBA/2 (D2) mice are relatively resistant.
• Susceptible strains exhibit higher parasitemia, anemia, and prolonged infection resolution.

Purpose of the Study:

• To investigate the role of the spleen in the immune response to Plasmodium yoelii 17X infection.
• To compare the cellular immune responses in susceptible (B6) and resistant (D2) mouse strains.

Main Methods:

• In vitro culture of spleen and lymph node cells from infected B6 and D2 mice with parasite antigens.
• Quantification of cell proliferation via [3H]thymidine uptake.
• Measurement of IFN-gamma and IL-5 secretion using ELISA.
• Assessment of infection outcomes following splenectomy.

Main Results:

• Splenectomy led to fatal outcomes in B6 mice but not D2 mice.
• Spleen cells from infected D2 mice showed strong proliferation to malaria antigen, while B6 cells showed weak or suppressed responses.
• Mesenteric lymph node cells from B6 and D2 mice proliferated only after splenectomy.
• Spleen cells from D2 mice produced higher levels of IFN-gamma compared to B6 mice.

Conclusions:

• The spleen is essential for resolving Plasmodium yoelii 17X infections, particularly in susceptible mouse strains.
• Splenectomy impairs the immune response, leading to increased susceptibility and mortality.
• Differential immune cell proliferation and cytokine production contribute to varying resistance levels against malaria.