Abstract
B cell function with age is decreased in class switch recombination (CSR), activation-induced cytidine deaminase (AID), and stability of E47 mRNA. The latter is regulated, at least in part, by tristetraprolin (TTP), which is increased in aged B cells and also negatively regulates TNF-α. In this study, we investigated whether B cells produce TNF-α, whether this changes with age, and how this affects their function upon stimulation. Our hypothesis is that in aging there is a feedback mechanism of autocrine inflammatory cytokines (TNF-α) that lowers the expression of AID and CSR. Our results showed that unstimulated B cells from old BALB/c mice make significantly more TNF-α mRNA and protein than do B cells from young mice, but after stimulation the old make less than the young; thus, they are refractory to stimulation. The increase in TNF-α made by old B cells is primarily due to follicular, but not minor, subsets of B cells. Incubation of B cells with TNF-α before LPS stimulation decreased both young and old B cell responses. Importantly, B cell function was restored by adding anti-TNF-α Ab to cultured B cells. To address a molecular mechanism, we found that incubation of B cells with TNF-α before LPS stimulation induced TTP, a physiological regulator of mRNA stability of the transcription factor E47, which is crucial for CSR. Finally, anti-TNF-α given in vivo increased B cell function in old, but not in young, follicular B cells. These results suggest new molecular mechanisms that contribute to reduced Ab responses in aging.
| Original language | English |
|---|---|
| Pages (from-to) | 279-286 |
| Number of pages | 8 |
| Journal | Journal of Immunology |
| Volume | 188 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 1 2012 |
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ASJC Scopus subject areas
- Immunology
Cite this
A molecular mechanism for TNF-α-mediated downregulation of B cell responses. / Frasca, Daniela; Romero, Maria; Diaz, Alain; Alter-Wolf, Sarah; Ratliff, Michelle; Landin, Ana Marie; Riley, Richard L; Blomberg, Bonnie B.
In: Journal of Immunology, Vol. 188, No. 1, 01.01.2012, p. 279-286.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - A molecular mechanism for TNF-α-mediated downregulation of B cell responses
AU - Frasca, Daniela
AU - Romero, Maria
AU - Diaz, Alain
AU - Alter-Wolf, Sarah
AU - Ratliff, Michelle
AU - Landin, Ana Marie
AU - Riley, Richard L
AU - Blomberg, Bonnie B
PY - 2012/1/1
Y1 - 2012/1/1
N2 - B cell function with age is decreased in class switch recombination (CSR), activation-induced cytidine deaminase (AID), and stability of E47 mRNA. The latter is regulated, at least in part, by tristetraprolin (TTP), which is increased in aged B cells and also negatively regulates TNF-α. In this study, we investigated whether B cells produce TNF-α, whether this changes with age, and how this affects their function upon stimulation. Our hypothesis is that in aging there is a feedback mechanism of autocrine inflammatory cytokines (TNF-α) that lowers the expression of AID and CSR. Our results showed that unstimulated B cells from old BALB/c mice make significantly more TNF-α mRNA and protein than do B cells from young mice, but after stimulation the old make less than the young; thus, they are refractory to stimulation. The increase in TNF-α made by old B cells is primarily due to follicular, but not minor, subsets of B cells. Incubation of B cells with TNF-α before LPS stimulation decreased both young and old B cell responses. Importantly, B cell function was restored by adding anti-TNF-α Ab to cultured B cells. To address a molecular mechanism, we found that incubation of B cells with TNF-α before LPS stimulation induced TTP, a physiological regulator of mRNA stability of the transcription factor E47, which is crucial for CSR. Finally, anti-TNF-α given in vivo increased B cell function in old, but not in young, follicular B cells. These results suggest new molecular mechanisms that contribute to reduced Ab responses in aging.
AB - B cell function with age is decreased in class switch recombination (CSR), activation-induced cytidine deaminase (AID), and stability of E47 mRNA. The latter is regulated, at least in part, by tristetraprolin (TTP), which is increased in aged B cells and also negatively regulates TNF-α. In this study, we investigated whether B cells produce TNF-α, whether this changes with age, and how this affects their function upon stimulation. Our hypothesis is that in aging there is a feedback mechanism of autocrine inflammatory cytokines (TNF-α) that lowers the expression of AID and CSR. Our results showed that unstimulated B cells from old BALB/c mice make significantly more TNF-α mRNA and protein than do B cells from young mice, but after stimulation the old make less than the young; thus, they are refractory to stimulation. The increase in TNF-α made by old B cells is primarily due to follicular, but not minor, subsets of B cells. Incubation of B cells with TNF-α before LPS stimulation decreased both young and old B cell responses. Importantly, B cell function was restored by adding anti-TNF-α Ab to cultured B cells. To address a molecular mechanism, we found that incubation of B cells with TNF-α before LPS stimulation induced TTP, a physiological regulator of mRNA stability of the transcription factor E47, which is crucial for CSR. Finally, anti-TNF-α given in vivo increased B cell function in old, but not in young, follicular B cells. These results suggest new molecular mechanisms that contribute to reduced Ab responses in aging.
UR - http://www.scopus.com/inward/record.url?scp=84855408862&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84855408862&partnerID=8YFLogxK
U2 - 10.4049/jimmunol.1003964
DO - 10.4049/jimmunol.1003964
M3 - Article
C2 - 22116831
AN - SCOPUS:84855408862
VL - 188
SP - 279
EP - 286
JO - Journal of Immunology
JF - Journal of Immunology
SN - 0022-1767
IS - 1
ER -