Immune responses following experimental human hookworm infection

Area of Science:

• Immunology
• Infectious Diseases
• Parasitology

Background:

• Human hookworm infections, caused by Necator americanus, are prevalent globally.
• Understanding the host immune response is crucial for developing effective treatments and vaccines.

Purpose of the Study:

• To characterize the immune response following primary and secondary human hookworm infection.
• To monitor clinical signs, hematological parameters, cytokine production, acute phase proteins, and antibody levels.

Main Methods:

• An adult volunteer was infected with Necator americanus larvae.
• Immune responses were assessed through clinical observation, blood counts, ex-vivo cytokine assays (IFN-gamma, IL-5, IL-13, IL-10), acute phase protein measurements (CRP, alpha1-AT), and antibody level determination.

Main Results:

• Primary infection induced dermatitis, edema, nausea, and abdominal discomfort.
• Eosinophil counts remained elevated (approx. 18%) throughout both infections.
• Transient production of IL-5, IL-13, and acute phase proteins (CRP, alpha1-AT) occurred, coinciding with larval migration and establishment.
• Negligible IFN-gamma and IL-10 levels were detected.
• Immune responses, except eosinophilia, declined within 4 months and were less pronounced upon reinfection.

Conclusions:

• The human immune response to Necator americanus involves transient Th2-biased cytokine production (IL-5, IL-13) and eosinophilia.
• The immune response is less pronounced during secondary infection, suggesting some degree of acquired immunity.