Abstract
The TLR4 ligand LPS causes mouse B cells to undergo IgE and IgG1 isotype switching in the presence of IL-4. TLR4 activates two signaling pathways mediated by the adaptor molecules MyD88 and Toll/IL-IR domain-containing adapter-inducing IFN-β (TRIF)-related adaptor molecule (TRAM), which recruits TRIF. Following stimulation with LPS plus IL-4, Tram(-/-) and Trif(-/-) B cells completely failed to express Cε germline transcripts (GLT) and secrete IgE. In contrast, Myd88(-/-) B cells had normal expression of Cε GLT but reduced IgE secretion in response to LPS plus IL-4. Following LPS plus IL-4 stimulation, Cγ1 GLT expression was modestly reduced in Tram(-/-) and Trif(-/-) B cells, whereas Aicda expression and IgG1 secretion were reduced in Tram(-/-), Trif(-/-), and Myd88(-/-) B cells. B cells from all strains secreted normal amounts of IgE and IgG1 in response to anti-CD40 plus IL-4. Following stimulation with LPS plus IL-4, Trif(-/-) B cells failed to sustain NF-κB p65 nuclear translocation beyond 3 h and had reduced binding of p65 to the Iε promoter. Addition of the NF-κB inhibitor, JSH-23, to wild-type B cells 15 h after LPS plus IL-4 stimulation selectively blocked Cε GLT expression and IgE secretion but had little effect on Cγ1 GLT expression and IgG secretion. These results indicate that sustained activation of NF-κB driven by TRIF is essential for LPS plus IL-4-driven activation of the Cε locus and class switching to IgE.
Publication types
-
Research Support, N.I.H., Extramural
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Adaptor Proteins, Vesicular Transport / genetics
-
Adaptor Proteins, Vesicular Transport / immunology*
-
Adaptor Proteins, Vesicular Transport / metabolism
-
Animals
-
B-Lymphocytes / drug effects
-
B-Lymphocytes / immunology
-
B-Lymphocytes / metabolism
-
Cell Survival / drug effects
-
Cell Survival / genetics
-
Cell Survival / immunology
-
Cytidine Deaminase / genetics
-
Cytidine Deaminase / immunology
-
Cytidine Deaminase / metabolism
-
Immunoblotting
-
Immunoglobulin Class Switching / drug effects
-
Immunoglobulin Class Switching / immunology*
-
Immunoglobulin E / genetics
-
Immunoglobulin E / immunology*
-
Immunoglobulin E / metabolism
-
Immunoglobulin G / genetics
-
Immunoglobulin G / immunology
-
Immunoglobulin G / metabolism
-
Immunoglobulin epsilon-Chains / genetics
-
Immunoglobulin epsilon-Chains / immunology
-
Immunoglobulin epsilon-Chains / metabolism
-
Immunoglobulin gamma-Chains / genetics
-
Immunoglobulin gamma-Chains / immunology
-
Immunoglobulin gamma-Chains / metabolism
-
Interleukin-4 / immunology
-
Interleukin-4 / pharmacology
-
Lipopolysaccharides / immunology
-
Lipopolysaccharides / pharmacology
-
Mice
-
Mice, 129 Strain
-
Mice, Inbred BALB C
-
Mice, Inbred C57BL
-
Mice, Knockout
-
Myeloid Differentiation Factor 88 / genetics
-
Myeloid Differentiation Factor 88 / immunology
-
Myeloid Differentiation Factor 88 / metabolism
-
Phenylenediamines / immunology
-
Phenylenediamines / pharmacology
-
Receptors, Interleukin / genetics
-
Receptors, Interleukin / immunology
-
Receptors, Interleukin / metabolism
-
Reverse Transcriptase Polymerase Chain Reaction
-
Signal Transduction / drug effects
-
Signal Transduction / genetics
-
Signal Transduction / immunology*
-
Toll-Like Receptor 4 / agonists
-
Toll-Like Receptor 4 / immunology*
-
Toll-Like Receptor 4 / metabolism
-
Transcription Factor RelA / antagonists & inhibitors
-
Transcription Factor RelA / immunology
-
Transcription Factor RelA / metabolism
Substances
-
4-methyl-N1-(3-phenylpropyl)benzene-1,2-diamine
-
Adaptor Proteins, Vesicular Transport
-
Immunoglobulin G
-
Immunoglobulin epsilon-Chains
-
Immunoglobulin gamma-Chains
-
Lipopolysaccharides
-
Myd88 protein, mouse
-
Myeloid Differentiation Factor 88
-
Phenylenediamines
-
Receptors, Interleukin
-
TICAM-1 protein, mouse
-
Ticam2 protein, mouse
-
Tlr4 protein, mouse
-
Toll-Like Receptor 4
-
Transcription Factor RelA
-
Interleukin-4
-
Immunoglobulin E
-
AICDA (activation-induced cytidine deaminase)
-
Cytidine Deaminase