Nature and nurture: overcoming constraints on immunity

Area of Science:

• Immunology
• Parasitology
• Epidemiology

Background:

• Parasitic infections are prevalent but unequally distributed, with often weak or slow-developing host immunity.
• High infection rates may result from socio-economic, climatic, and husbandry factors, alongside environmental and genetic constraints on resistance.

Purpose of the Study:

• To explore environmental and genetic factors that constrain the development of host resistance to parasitic infections.
• To understand the interplay of these factors to inform strategies for increasing population and individual resistance, especially with upcoming anti-parasite vaccines.

Main Methods:

• Review of immunological and epidemiological studies on parasitic infections in humans and animals.
• Analysis of immunogenetic data concerning host-parasite interactions.
• Discussion of environmentally induced constraints (nutrition, early life exposure) and genetically determined constraints (MHC, T-cell function, inflammatory responses).

Main Results:

• Environmental factors like nutritional inadequacies and early-life infections significantly impede resistance to helminth parasites.
• Genetic factors, including Major Histocompatibility Complex (MHC) and Class II molecules, influence T-cell function and immune responses to parasites like Plasmodium, Leishmania, Schistosoma, and intestinal nematodes.
• Parasites can induce constraints that down-regulate protective immune responses.

Conclusions:

• Overcoming environmental and genetic constraints is essential for enhancing host resistance to parasitic infections.
• A comprehensive understanding of these constraints is critical for the successful development and deployment of anti-parasite vaccines.
• Further research into parasite-induced immune suppression is needed.