TCR gamma delta cells: mysterious cells of the immune system.

Gamma delta cells participate in pathogenic infections and autoimmune conditions, yet, almost a decade after their discovery, little is known regarding their TCR repertoire or effector functions. Unlike MHC-restricted antigen recognition employed by TCR alpha beta cells, TCR gamma delta cells can recognize whole unprocessed antigens in an MHC- independent manner. The nature of positive and negative selection used to shape the repertoire of TCR gamma delta cells is unclear, especially in the nonlymphoid tissues where these cells predominate.

The gamma chain of the high-affinity receptor for IgE is a major functional subunit of the T-cell antigen receptor complex in gamma delta T lymphocytes.

T-cell activation is a consequence of the clonotypic T-cell antigen receptor (TCR) binding to an antigen followed by signal transduction via the invariant subunits of the TCR/CD3 complex. gamma delta TCR cells are a small subset of T cells that populate both the epithelial and lymphoid tissues and have unique antigen specificity and function. However, the composition of invariant chains within the gamma delta TCR/CD3 complex has not been well characterized.

Role of gamma delta T cells in murine collagen-induced arthritis.

Murine collagen-induced arthritis (CIA) is a T cell-mediated disease which is induced by injection of type II collagen. Previous studies have shown that CD4+ cells which express particular V beta TCR genes are involved in the induction of arthritis in this model. In the present report we demonstrate that CD4-, CD8-, TCR gamma delta cells are present in arthritic joints, expanded in peripheral lymphoid tissue of DBA/1 lac J mice with CIA, and respond in vitro to the anti-TCR gamma delta mAb UC7-13D5 (13D5).

CD28-mediated costimulation is necessary for the activation of T cell receptor-gamma delta+ T lymphocytes.

The role of costimulation in the activation of TCR-gamma delta cells in normal mice and mice transgenic (tg) for a TCR-gamma delta receptor was investigated. Activation of TCR-gamma delta cells required two signals. One signal was mediated by TCR occupancy, whereas a second signal was provided by accessory cells.

Peripheral T cell receptor gamma delta variable gene repertoire maps to the T cell receptor loci and is influenced by positive selection.

Although the mechanisms that determine TCR-alpha beta V gene repertoire are well studied, the genetic influences involved in TCR-gamma delta repertoire development are unclear. Unlike the TCR-gamma delta populations that localize in epithelial tissues, the circulating peripheral TCR-gamma delta V region repertoire is quite diverse. Previous studies have shown that three TCR-gamma chains and at least six TCR-V delta genes are expressed by splenic TCR-gamma delta cells.

A murine CD4-, CD8- T cell receptor-gamma delta T lymphocyte clone specific for herpes simplex virus glycoprotein I.

The role of TCR-gamma delta T lymphocytes in immune responses is currently not well understood. TCR-gamma delta cells have a limited repertoire suggesting that TCR-gamma delta T a limited number of evolutionarily conserved Ag such as nonpolymorphic MHC and heat shock proteins. TCR-gamma delta T lymphocytes appear in enhanced numbers in skin lesions produced by Mycobacterium leprae and in the synovial fluid of joints affected by rheumatoid arthritis, raising the possibility that this subset of T lymphocytes may play a role in control of infectious processes and in autoimmune diseases.

Laparoscopic salpingectomy using conventional laparoscopy equipment.

Laparoscopic surgery has gained wide acceptance in the treatment of ectopic pregnancy. When compared with conventional surgical techniques, the laparoscopic approach reduces perioperative morbidity, hospital costs, length of hospital stay, and recovery time. Laparoscopic surgery, however, often requires special surgical skills and expensive equipment.

Repertoire development and ligand specificity of murine TCR gamma delta cells.

During the past several years, we have been studying the circulating TCR gamma delta cells expressed in peripheral lymphoid tissues. Biochemical and molecular characterization of the TCR gamma delta heterodimers present on these TCR gamma delta cells identified 3 TCR gamma proteins, V gamma 2-C gamma 1, V gamma 1.2-C gamma 2, and V gamma 1.

CD4-, CD8- gamma/delta cells from normal mice respond to a syngeneic B cell lymphoma and can induce its differentiation.

Lymph nodes and spleens from normal unimmunized mice contain small numbers of CD3+, CD4-, CD8- (double negative, DN) T cells. Of these, approximately one-third express the marker Ly-5(B220) in a form previously seen only on normal B cells and a population of DN T cells found in mice genetically prone to develop autoimmunity. DN T cells proliferate when co-cultured with a syngeneic surface Ig+ lymphoma, CH12.

Gross displacement of the mandibular canal: a radiographic sign of benign fibro-osseous bone disease.

Gross displacement of the mandibular neurovascular canal is an uncommon phenomenon. It is suggested that displacement of the canal should be included as one of the possible diagnostic criteria of benignity of disease of the mandible. Superior displacement of the canal should be considered an unusual but observable characteristic of benign fibro-osseous disease.