We report the discovery of a new B-lymphocyte-specific enhancer-binding protein. A series of gel retardation assays using fragments that scan the -2172 to -1180 region of the major histocompatibility complex class II gene E alpha reveal a site (W) that serves as the recognition sequence for two nuclear proteins, one B-cell restricted and the other ubiquitously occurring. Certain characteristics...

The immune response consists of two main components: humoral immunity represented by B lymphocytes and cellular immunity maintained by the T lymphocytes. Immunoglobulins, produced by B-lymphocytes, are the main mediators of humoral immunity, and deficiencies at this level affect the body's response to infection. Plasmocytes produce nine antibody izotypes: immunoglobulins G (IgG1, IgG2, IgG3, Ig...

We have defined two subpopulations of B lymphocytes in chronic lymphocytic leukemia (CLL). The major variant (termed typical) was characterized by the presence of a relatively homogeneous population of small-to-medium-sized lymphocytes with low-density SmIgM and no evidence of intracellular Ig synthesis. A minor group (termed atypical) was identified by the presence of a pleomorphic cell popula...

In semisolid agar cultures containing mercaptoethanol, cells from the spleen, lymph nodes, marrow, peritoneal cavity, thoracic duct, and blood of normal mice generated clusters and colonies of up to 3,000 cells. Colony numbers and growth were markedly enhanced by the addition of sheep red cells. The frequency of colony-forming cells in the spleen or lymph nodes was 0.5-2.0%, and cluster forming...

BACKGROUND Although cell mediated immunity is primarily thought to mediate the pathogenesis of sarcoidosis, the presence of immunoglobulins, immune complexes and complement suggests that processes of humoral immunity may contribute to immunopathology in sarcoid lesions. To test this hypothesis, the distribution of B lymphocytes in paraffin embedded sarcoid lesions in mediastinal lymph nodes and...

T he immune system requires the cognate interactions of T cells, B cells, and antigen-presenting cells to respond to invading antigens/pathogens. However, the peripheral lymphoid organs where immune responses occur are not simply made of a random mixture of T cells, B cells, and antigen-presenting cells. Rather they are organized into ruicroanatomic compartments that are composed mainly of T ce...

Follicular dendritic cells (FDCs) are unique immune system cells that contribute to the maintenance of humoral (i.e. antibody) immune responses. These cells are located in the follicles of secondary lymphoid tissues (e.g. lymph nodes and spleen), where they trap and retain antigens in the form of highly immunogenic immune complexes (ICs). FDC-ICs are composed of antigen plus specific antibody a...

OBJECTIVE To identify the presence of B lymphocytes in the rhinoscleroma granulomas as a possible precursor of plasma cells, whose presence has always been described but whose role is still unclear. STUDY DESIGN Case series with chart review. SETTING Sapienza University of Rome. METHODS The study was carried out on 6 patients (3 women, 3 men). The following parameters were examined for ea...

Recent observations using multiphoton intravital microscopy (MP-IVM) have uncovered an unexpectedly high lymphocyte motility within peripheral lymph nodes (PLNs). Lymphocyte-expressed intracellular signaling molecules governing interstitial movement remain largely unknown. Here, we used MP-IVM of murine PLNs to examine interstitial motility of lymphocytes lacking the Rac guanine exchange factor...