Chronic, patent Plasmodium berghei malaria in splenectomized mice

Area of Science:

• Immunology
• Parasitology
• Infectious Diseases

Background:

• Splenectomy in mice can lead to chronic Plasmodium berghei infections, often with high parasitemia.
• True immunity is typically not achieved, but a degree of resistance can develop.

Purpose of the Study:

• To investigate the development of resistance and immunity to Plasmodium berghei in splenectomized mice.
• To compare the effects of infection suppression versus radical cure on subsequent resistance.

Main Methods:

• Splenectomized mice were infected with Plasmodium berghei.
• Infections were either suppressed (sulfonamide) or cured (chloroquine) after 2 weeks of patency.
• Resistance to superinfection was assessed.

Main Results:

• A patent infection of at least 2 weeks was required for resistance development.
• Sulfonamide treatment resulted in a higher proportion of resistant mice compared to chloroquine treatment.
• Some mouse strains (B10LP) spontaneously cleared chronic infections, unlike others (C57BL/Rij, BALB/c).
• Chronic infections caused limited anemia, elevated liver enzymes, and reduced immune reactivity compared to acute lethal infections.

Conclusions:

• Splenectomy-associated Plasmodium berghei infection in mice leads to chronic states with limited pathology.
• Infection suppression strategies may be more effective than radical cure for inducing resistance to superinfection in this model.
• Strain-specific differences exist in the ability to clear chronic Plasmodium berghei infections.