title: Immunohistologic detection of the primary follicle (PF) in human fetal and newborn lymph node anlages.
abstract: The primary follicle (PF) emerges as a globular nest of follicular dendritic cells (FDC) and lymphocytes in the lymph node anlage in the 16th gestational week. It increases in size with age but no germinal center is found until several months later, after birth. Using a panel of monoclonal antibodies, the authors have defined phenotypes of component cells of the PF. The PF contains a B-cell population including IgM+, CD20+, CD21+, and CD24+ cells, together with a T-cell population including CD3+, CD4+, CD5+, and CD8+ but no IgG+ cells. It also contains many CD5+ B cells and several IgD+ and alkaline phosphatase-positive cells but few CD15+, CD25+, CD30+, CD38+, and Ki-67+ cells. CD24+ and dendritic reticulum (DRC)-1+ cells show an irregular meshwork pattern in the PF. CD5+ B cells appear even before the formation of the PF and increase after formation of the PF. The lymphocytic phenotype of the PF is similar to that of the mantle zone of the secondary follicle. The phenotypic characteristics indicate that the PF appears as an aggregation of CD5+ B cells and plays an important role as the ancestor of the secondary follicle as well as helper T cells and FDC.
authors.affiliation: Department of Pathology, Fukushima Medical College, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Asano
authors.forename: Y
authors.initials: Y
authors.lastname: Akaike
authors.forename: T
authors.initials: T
authors.lastname: Muramatsu
authors.forename: M
authors.initials: M
authors.lastname: Mochizuki
authors.forename: T
authors.initials: T
authors.lastname: Tsuda
authors.forename: H
authors.initials: H
authors.lastname: Wakasa
mesh_terms: D015703:Antigens, CD / Q000032:analysis; D018951:Antigens, CD20; D000944:Antigens, Differentiation, B-Lymphocyte / Q000032:analysis; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology; D051927:CD24 Antigen; D017252:CD3 Complex / Q000032:analysis; D015704:CD4 Antigens / Q000032:analysis; D018956:CD5 Antigens; D016827:CD8 Antigens / Q000032:analysis; D003713:Dendritic Cells / Q000737:chemistry / Q000166:cytology*; D005333:Fetus / Q000737:chemistry / Q000166:cytology*; D005455:Fluorescent Antibody Technique; D006801:Humans; D007150:Immunohistochemistry; D007231:Infant, Newborn; D019394:Ki-67 Antigen; D008198:Lymph Nodes / Q000737:chemistry / Q000166:cytology* / Q000196:embryology*; D008214:Lymphocytes / Q000737:chemistry / Q000166:cytology*; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins / Q000032:analysis; D009687:Nuclear Proteins / Q000032:analysis; D010641:Phenotype; D017464:Receptors, Complement 3d / Q000032:analysis; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology
chemical_list: D015703:Antigens, CD; D018951:Antigens, CD20; D000944:Antigens, Differentiation, B-Lymphocyte; D051927:CD24 Antigen; C497889:CD24 protein, human; D017252:CD3 Complex; D015704:CD4 Antigens; D018956:CD5 Antigens; D016827:CD8 Antigens; D019394:Ki-67 Antigen; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D017464:Receptors, Complement 3d