When T-helper cells don't help: immunopathology during concomitant infection

Area of Science:

• Integrates evolutionary ecology with immunology to explain T-helper cell-mediated immunopathology.
• Focuses on the ecological and evolutionary drivers of disease caused by the immune system.

Background:

• Immunopathology arises when the immune system causes disease instead of curing it.
• Autoimmune, allergic, and infection-related diseases impact millions globally.
• T-helper cell responses are crucial for combating different parasite types.

Purpose of the Study:

• To analyze infection-related immunopathology through the lens of evolutionary ecology.
• To investigate how T-helper cell response errors and coinfection contribute to disease.
• To explore the ultimate causes of immunopathology in multiparasite environments.

Main Methods:

• Review and analysis of T-helper cell-mediated immunopathology within an evolutionary ecology framework.
• Examination of proximate causes, including T-helper cell subset errors and immunophenotype-environment mismatches.
• Case study using mouse models infected with Schistosoma mansoni and Toxoplasma gondii to illustrate coinfection effects.

Main Results:

• Mismatches between the immune phenotype and the parasitic environment can decrease host fitness.
• Coinfection can exacerbate immunopathology due to T-helper response polarization, hindering concurrent effective responses.
• T-helper response polarization is an ultimate cause of immunopathology in multiparasite settings.

Conclusions:

• Understanding T-helper cell polarization and its evolutionary basis is key to addressing infection-related immunopathology.
• Coinfection presents significant challenges to the immune system, potentially leading to severe pathology.
• Integrating evolutionary ecology and immunology offers mutual benefits for understanding host-parasite interactions and immune function.