Infection-induced type I interferons activate CD11b on B-1 cells for subsequent lymph node accumulation

Area of Science:

• Immunology
• Virology
• Cell Biology

Background:

• B-1a lymphocytes are key in early immune responses, producing protective IgM during influenza infection.
• These cells rapidly migrate to mediastinal lymph nodes (MedLNs) upon infection.

Purpose of the Study:

• To elucidate the mechanism by which B-1 cells accumulate in MedLNs during influenza.
• To identify the specific signals and molecular players involved in B-1 cell trafficking.

Main Methods:

• Utilized vascular mimetic flow chambers to study B-1 cell adhesion under shear stress.
• Conducted in vivo trafficking experiments to track B-1 cell migration.
• Investigated the role of type I interferons and integrins in B-1 cell homing.

Main Results:

• Influenza-induced type I interferons directly stimulate B-1 cells and are essential for their MedLN accumulation.
• Type I interferons enhance B-1 cell adhesion by inducing high-affinity integrin conformations.
• CD11b was identified as the critical interferon-activated integrin for B-1 cell accumulation in MedLNs.

Conclusions:

• CD11b on B-1 cells acts as a sensor for infection-induced innate signals.
• This sensing mechanism facilitates rapid B-1 cell sequestration into lymphoid tissues.
• The study regulates the accumulation of polyreactive IgM producers at infection sites.