T. Muris Infection Dynamics of a Fresh, Wild Isolate: Is the Established E Isolate Still Relevant?

Area of Science:

• Immunology
• Parasitology
• Infectious Diseases

Background:

• Laboratory parasite models are crucial for studying host-parasite interactions.
• Long-term laboratory maintenance can lead to genetic selection in parasites.
• This selection may alter parasite virulence and host immune responses.

Purpose of the Study:

• To compare the infectivity and host immune response elicited by a laboratory-adapted Trichuris muris isolate (E) versus a recently isolated wild strain (M).
• To assess the relevance of established laboratory parasite models in the context of host-parasite dynamics.

Main Methods:

• Infection of C57BL/6 mice with high and low doses of T. muris E and M isolates.
• Quantification of adult worm burden post-infection.
• Analysis of host immune responses including cytokine secretion (TNF-α, IL-10) and antibody levels (IgG1, IgG2c).
• Flow cytometry assessment of CD4+ T effector-memory cell populations (T-bet+, ICOS+).

Main Results:

• The wild M isolate exhibited significantly higher adult worm survival compared to the lab-adapted E isolate following high-dose infection.
• Worm persistence of the M isolate correlated with elevated TNF-α and IL-10 production upon re-stimulation.
• M isolate infection led to increased serum IgG1 and IgG2c levels and a higher frequency of T-bet+ and ICOS+ CD4+ T effector-memory cells.
• Differences in host response were less pronounced in low-dose infections.

Conclusions:

• Laboratory-adapted parasite isolates may exhibit altered virulence and immunogenicity compared to wild strains.
• Host immune responses, including T cell populations and antibody production, are differentially modulated by T. muris isolates.
• Regular evaluation of laboratory parasite strains against fresh isolates is necessary to ensure the continued relevance of these models for understanding parasitic infections.