AUTHOR=Martinez-Murillo Paola , Pramanik Lotta , Sundling Christopher , Hultenby Kjell , Wretenberg Per , Spångberg Mats , Karlsson Hedestam Gunilla B. 

TITLE=CD138 and CD31 Double-Positive Cells Comprise the Functional Antibody-Secreting Plasma Cell Compartment in Primate Bone Marrow

JOURNAL=Frontiers in Immunology

VOLUME=Volume 7 - 2016

YEAR=2016

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2016.00242

DOI=10.3389/fimmu.2016.00242

ISSN=1664-3224

ABSTRACT=Abstract 
Plasma cells (PCs) are defined as terminally differentiated B cells that secrete large amounts of immunoglobulin (Ig). Plasma cells that reside in the bone marrow (BM) are responsible for maintaining long-term antibody responses after infection and vaccination, while plasma cells present in the blood are generally short-lived. In rhesus macaques, a species frequently used for the evaluation of human vaccines, B cells resemble those found in humans. However, a detailed characterization of BM-resident rhesus plasma cell phenotype and function is lacking. Here, we examined Ig secretion of distinct rhesus CD138+ populations by B cell ELISpot analysis to couple phenotype with function. We demonstrate that the CD20low/-CD138+CD31+ BM population was highly enriched for antibody-secreting cells with IgG being the predominant isotype (60%), followed by IgA (33%) and IgM (7%). Transmission electron microscopy (TEM) analysis confirmed plasma cell enrichment in the CD20low/-CD138+CD31+ population with cells containing nuclei with “spokes of a wheel” chromatin structure and prominent rough endoplasmic reticulum. This panel also stained human BM PCs and allowed a clear distinction between BM PCs and short-lived peripheral plasma cells, providing an improved strategy to isolate PCs from rhesus bone marrow for further analysis.