Rapid proliferation and differentiation of a subset of circulating IgM memory B cells to a CpG/cytokine stimulus in vitro
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1
Pontificia Universidad Javeriana, Instituto de Genética Humana, Facultad de medicina, Colombia
Human circulating IgM+ memory B cells (CD27+IgM+ (mBc IgM)) are not fully characterized. Therefore, many aspects of their biology and composition remain to be elucidated. Currently, it is unclear if there are functional and/or phenotypic differences between IgM+ mBc, naïve Bc, or switched mBc. Also, it is unclear if there are differences among IgM+ mBc subsets.
When compared to naïve Bc, lower frequencies of IgM+ mBc expressed CD40, BAFF-R, CD21, CD73 and IL21-R, but higher frequencies of them expressed CD95, CD11c, CD43, TLR9, PD-1, CD122 and CD45RO. When compared to switched mBc, IgM+ mBc showed higher frequencies of cells expressing BAFF-R, CD40, PD-1, IL21-R, TLR9 and CD122, but lower frequencies expressing CD95 and CD73. Purified IgM+ mBc stimulated in vitro with CpG, IL-2, IL-6, and IL-10 for 4 days displayed higher frequencies of cells that proliferated and acquired the phenotype of antibody secreting cells, compared to naive Bc and switched mBc. Besides, with this same stimulus, a low frequency of IgM+ mBc switched isotype in vitro.
The analysis of the distribution of RV-specific mBc among circulating IgM+ mBc population allowed to differentiate two IgM+ mBc subsets: IgMhi IgDlo (IgMhi) and IgMlo IgDhi (IgMlo); RV-specific mBc are enriched in the IgMhi subset.
In conclusion, in response to a CpG and cytokine based polyclonal stimulus a higher frequency of the circulating IgM+ mBc population differentiates and proliferates, compared to naïve Bc and switched mBc. The RV-specific mBc distribution suggests that IgMhi and IgMlo may be subsets with differences in function and phenotype.
Acknowledgements
We would like to thank the subjects that participated in this study for their generosity, the Radiotherapy Unit, Centro Javeriano de Oncología, and the Hemocentro Distrital for providing samples.
Keywords:
memory B cell,
circulating memory B cell,
IgM,
IgG,
CpG
Conference:
IMMUNOCOLOMBIA2015 - 11th Congress of the Latin American Association of Immunology - 10o. Congreso de la Asociación Colombiana de Alergia, Asma e Inmunología, Medellin, Colombia, 13 Oct - 16 Oct, 2015.
Presentation Type:
Oral Presentation
Topic:
Adaptive Immunity
Citation:
Vásquez
AC,
Franco
MA and
Angel
J
(2015). Rapid proliferation and differentiation of a subset of circulating IgM memory B cells to a CpG/cytokine stimulus in vitro.
Front. Immunol.
Conference Abstract:
IMMUNOCOLOMBIA2015 - 11th Congress of the Latin American Association of Immunology - 10o. Congreso de la Asociación Colombiana de Alergia, Asma e Inmunología.
doi: 10.3389/conf.fimmu.2015.05.00338
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Received:
15 Apr 2015;
Published Online:
15 Sep 2015.
*
Correspondence:
Dr. Manuel A Franco, Pontificia Universidad Javeriana, Instituto de Genética Humana, Facultad de medicina, Bogotá, Bogotá, Colombia, mafranco@javeriana.edu.co
Dr. Juana Angel, Pontificia Universidad Javeriana, Instituto de Genética Humana, Facultad de medicina, Bogotá, Bogotá, Colombia, Jangel@javeriana.edu.co