The origin of marginal zone B cells in the rat.

The marginal zone is a unique compartment that is only found in the spleen. Rat marginal zone B cells (MZ-B) can be distinguished from other B cells, e.g.

Expression of HIS50 Ag: a rat homologue of mouse heat-stable antigen and human CD24 on B lymphoid cells in the rat.

Recently, a cDNA encoding a newly identified rat antigen (HIS50 Ag) that binds to monoclonal antibody (mAb) HIS50 was cloned and shown to be homologous to cDNA encoding murine heat-stable antigen (HSA) and human CD24. Here we show that, like CD24 and HSA, at least part of HIS50 Ag is inserted into the plasma membrane by a glycosylphosphatidylinosito: (GPI)-lipid linkage and we describe its expression in rat haemolymphopoietic tissues. HIS50 Ag expression was almost exclusively confined to B lymphoid cells, the vast majority of T lymphoid cells, erythroid and myeloid cells were HIS50+.

Monoclonal immunoglobulin A derived from peritoneal B cells is encoded by both germ line and somatically mutated VH genes and is reactive with commensal bacteria.

We transferred peritoneal cells from BALB/c mice into C.B17 scid/scid mice. Six to eight months after injection, only cells with the B1 phenotype were retained in the spleens and peritoneal cavities of these mice.

Identification and kinetics of two recently bone marrow-derived B cell populations in peripheral lymphoid tissues.

In rats, the glycoprotein Thy-1 is expressed on recently bone marrow (BM)-generated B cells but not on mature recirculating follicular (RF) B cells. Here we demonstrate that Thy-1+ B cells consist of two phenotypically distinct, but developmentally related, populations: a population of newly formed (NF) B cells (IgMbr-IgDdu) that give rise to the second, less immature, Thy-1+ population of so-called early recirculating follicular (ERF) B cells (Thy-1+IgMduIgDbr) cells. These cells ultimately develop to RF-B cells (Thy-1-IgMbrIgDdu).

Kinetics of B cell subpopulations in peripheral lymphoid tissues: evidence for the presence of phenotypically distinct short-lived and long-lived B cell subsets.

A small proportion of the sIg+ B lymphocytes in peripheral lymphoid organs [22% in spleen and 6% in lymph node (LN)] in rat carries the Thy-1 antigen. These Thy-1+ B cells represent newly formed bone marrow (BM) derived (or immature) B cells. In this study we investigated the kinetic behavior of Thy-1+ and Thy-1- B cells in various lymphoid tissues.

Kinetics of peritoneal B-1a cells (CD5 B cells) in young adult mice.

In the mouse, conventional B cells are continuously generated from precursor cells located in the bone marrow (BM), whereas the small subset of B-1 cells (formerly called Ly-1 B cells) constitute a self-replenishing population of cells. Here we studied the kinetics of murine peritoneal B-1a cells (i.e.

In rat B lymphocyte genesis sixty percent is lost from the bone marrow at the transition of nondividing pre-B cell to sIgM+ B lymphocyte, the stage of Ig light chain gene expression.

The cycling B precursor cells in rat bone marrow (BM) that carry the B220 antigen and no surface Ig daily produce 780 million new cells. The pool of recirculating B lymphocytes in the rat, however, renew at a rate of only about 40 million cells/day. To analyze at which stages in B lymphocyte genesis the cell loss occurs, we identified post-mitotic cells in the rat BM B lineage, and determined their renewal rates.

LAMA tumor in the rat as an experimental model for pre-B-cell leukemia.

A late pre-B-cell leukemia model in the rat, the LAMA tumor, is described. A mouse monoclonal antibody (HIS30) was developed against LAMA cells. HIS30 reacts with a membrane antigen in tumor tissue, whereas its reactivity with normal tissues is limited to the zona glomerulosa of the adrenal cortex and to the adrenal medulla.

A stathmokinetic study of B lymphocytopoiesis in rat bone marrow: proliferation of cells containing cytoplasmic mu-chains, terminal deoxynucleotidyl transferase and carrying HIS24 antigen.

In rat bone marrow (BM), the B lineage surface antigen HIS24 is expressed by all surface mu chain-bearing (s mu+) B cells, by cytoplasmic mu chain-containing (c mu+s mu-) pre-B cells and TdT+ cells, and by lymphoid cells lacking both mu and TdT. Because TdT+ and HIS24+TdT-mu- cells may represent stages in B lymphocytopoiesis before mu chain expression, we investigated their kinetics. The metaphase arrest method was combined with immunofluorescence staining to detect proliferation and to quantitate cell production in the BM pre-B, TdT+, and HIS24+TdT-mu- compartments.

B lymphocyte differentiation in the rat: production and characterization of monoclonal antibodies to B lineage-associated antigens.

Three mouse monoclonal antibodies (mAb) directed against rat B lineage antigens were produced. The mAb, designated HIS14 (IgG1), HIS22 (IgM) and HIS24 (IgG2b), were characterized for binding to lymphoid and nonlymphoid tissues by immunoperoxidase staining of frozen sections and by (double-) immunofluorescence staining of single cell suspensions from lymphoid organs. HIS14 recognized a pan B cell determinant: it reacted with virtually all cells of each anatomic B cell compartment and with about 95% of surface (s)Ig+ cells in thoracic duct lymph and in suspensions of spleen and lymph nodes.

B lymphocyte-associated antigens on terminal deoxynucleotidyl transferase-positive cells and pre-B cells in bone marrow of the rat.

To investigate early stages of B lymphocytopoiesis in rat bone marrow (BM) before the expression of surface IgM (s mu), the populations of cytoplasmic mu-chain-positive (c mu+) pre-B cells and terminal deoxynucleotidyl transferase-positive (TdT+) cells were studied by double immunofluorescence microscopy. B lymphocytes that were s mu+ constituted 5%, c mu+s mu- pre-B cells 23%, and TdT+ cells 4% of nucleated cells in the BM of juvenile rats. TdT+ and pre-B cells ranged between 7 and 17 microns in diameter.

Homing of germinal-center cells into germinal centers of lymph node via afferent lymphatics. An autoradiographic study in rabbits.

Affinity of lymphoid cells for the microenvironment of germinal centers (GC), as detectable in transfer experiments by rapid homing in spleen GC from the blood, is a capacity expressed by only a subset of lymphoid cells, in particular by those constituting a GC. However, when introduced into the blood stream, these cells do not home into GC of lymph nodes and gut-associated lymphoid tissues. To investigate further this homing inability for high endothelial venule (HEV)-containing lymphoid tissues, GC cells isolated from donor rabbit appendix were labeled in vitro with 3H-leucine and injected into an afferent lymph vessel of recipient popliteal lymph nodes.

Germinal centers and the B cell system. VIII. Functional characteristics and cell surface markers of germinal center cell subsets differing in density and in sedimentation velocity.

Germinal center cells from the rabbit appendix were fractionated by velocity sedimentation and isopycnic gradient centrifugation. Subsets were analysed with respect to cell size and surface markers, and were functionally characterized by testing the capacities for primary antibody synthesis, memory cell production, and formation of new germinal centers in an autologous transfer system. The migratory behaviour of the germinal center cell subsets within the spleen of homologous recipients was also studied using autoradiography.

Lymphocyte migration across major histocompatibility barriers in splenectomized rats.

Localisation and migration patterns of iv injected radio-labelled thoracic duct (TD) lymphocytes were studied in particular with regard to passage through lymph nodes and re-entry into thoracic duct lymph. To avoid unwanted splenic sequestration of migrating lymphocytes presenting alloantigens to the recipient, only splenectomized recipients were used. Donor cells and recipients differed at the MHC (RT-1) locus, either in fully allogeneic (AO -- greater than BN and v.