Experimental Chagas' disease in complement-deficient mice and guinea pigs

Area of Science:

• Immunology
• Infectious Diseases
• Parasitology

Background:

• Trypanosoma cruzi causes Chagas disease, a significant global health concern.
• The complement system is a crucial part of innate immunity, but its role in T. cruzi infections is not fully understood.
• Genetic deficiencies in complement components offer a model to study its specific functions.

Purpose of the Study:

• To investigate the role of complement-mediated lysis and the classical complement pathway in controlling Trypanosoma cruzi infections.
• To compare the course of T. cruzi infection in genetically complement-deficient and normocomplementemic animals.

Main Methods:

• Comparison of T. cruzi (House 510 strain) infection in C5-deficient mice versus congenic normocomplementemic mice.
• Assessment of parasitemia, C3 levels, and mortality rates in infected mice.
• Comparison of T. cruzi infection in complement component 4 (C4)-deficient guinea pigs versus normocomplementemic guinea pigs.
• Evaluation of infection course, subpatent infection persistence, and mortality in guinea pigs.

Main Results:

• Mice deficient in C5 showed similar or lower parasitemia compared to normocomplementemic controls, with no significant difference in mortality.
• C3 levels were generally unaffected in the C5-deficient mice.
• Guinea pigs deficient in C4 did not exhibit significant differences in infection course, persistence, or mortality compared to normocomplementemic controls.

Conclusions:

• Complement-mediated lysis does not appear to play a significant role in controlling T. cruzi (House 510) infections in mice.
• The classical complement pathway likely plays a minimal role, if any, in resistance to T. cruzi (House 510) infections in guinea pigs.