IFNγ-Producing B Cells Play a Regulating Role in Infection-Mediated Inhibition of Allergy

Area of Science:

• Immunology
• Infectious Disease
• Allergy Research

Background:

• The hygiene hypothesis proposes infections may prevent allergies, but mechanisms are unclear.
• Previous work showed Chlamydia muridarum (Cm) lung infection inhibits allergic inflammation via dendritic and T cells.
• This study investigates the role of B cells in Cm-mediated allergy modulation.

Purpose of the Study:

• To explore the role of B cells in Chlamydia muridarum-infected mice regarding allergic responses.
• To determine if B cells from Cm-infected mice can inhibit allergic airway inflammation.
• To elucidate the mechanism by which Cm-modulated B cells affect allergic reactions.

Main Methods:

• Adoptive transfer of B cells from Cm-infected mice (Cm-B cells) and naive mice into recipient mice.
• Induction of allergic airway inflammation using ovalbumin (OVA).
• Measurement of airway eosinophilia, mucus production, Th2 cytokines, IgE/IgG1 antibodies, and IFNγ production by B cells.
• Inhibition of IFNγ using monoclonal antibodies during adoptive transfer.

Main Results:

• Adoptive transfer of Cm-B cells, but not naive B cells, significantly inhibited OVA-induced allergic airway eosinophilia and mucus overproduction.
• Cm-B cells suppressed Th2 cytokine responses and reduced total and OVA-specific IgE/IgG1 antibodies.
• B cells from Cm-infected mice produced higher levels of IFNγ.
• Blocking IFNγ abolished the inhibitory effect of Cm-B cells on allergic reactions.

Conclusions:

• B cells modulated by Chlamydia muridarum lung infection play a regulatory role in allergic airway responses.
• IFNγ production by these B cells is crucial for suppressing allergic inflammation.
• These findings offer new insights into potential therapeutic targets for preventing and treating allergic diseases.