Leucocyte recruitment during enteric nematode infection.

Area of Science:

• Immunology
• Parasitology
• Cell Biology

Background:

• Resolution of Trichinella spiralis infection relies on a T helper 2 (Th2) immune response.
• Mast cells and T cells are critical immune cells involved in combating this infection.
• Previous research demonstrated that mast cell migration to the gut during infection is dependent on integrin beta 7 expression.

Purpose of the Study:

• To investigate whether mast cell dysfunction in beta 7-deficient hosts is due to impaired binding of alpha 4 beta 7 to MAdCAM-1 or alpha E beta 7 to E-cadherin.
• To elucidate the specific roles of alpha 4 beta 7 and alpha E beta 7 integrins in mast cell homing to the intestine during Trichinella spiralis infection.

Main Methods:

• C57BL/6 mice were infected with Trichinella spiralis.
• Blocking monoclonal antibodies against alpha E, alpha 4, or beta 7 integrins were administered.
• Mast cell infiltration (mastocytosis) and T cell migration (CD3+ cells) into the intestine were assessed.

Main Results:

• Antibody-mediated blockade of alpha E, alpha 4, or beta 7 integrins significantly reduced mast cell numbers in the gut.
• In contrast, these antibody treatments did not impede the migration of CD3+ T cells into the intestine.
• These findings suggest integrin redundancy for lymphocyte migration but not for mast cells.

Conclusions:

• Both alpha E beta 7 and alpha 4 beta 7 integrins are essential for mast cell entry into or maturation within the gut during Trichinella spiralis infection.
• Integrins play distinct roles in immune cell trafficking, with mast cells exhibiting less redundancy compared to lymphocytes.
• Understanding these integrin-mediated mechanisms is crucial for developing targeted therapies against intestinal nematode infections.