Antigen

About: Antigen is a research topic. Over the lifetime, 170233 publications have been published within this topic receiving 6982342 citations. The topic is also known as: antibody generator & Antigen.

Monoclonal antibodies to nucleic acid-containing cellular constituents: probes for molecular biology and autoimmune disease

Abstract: Mice of the strain MRL/Mp-lpr/lpr develop a lupus erythematosus-like syndrome that includes the production of autoantibodies specific for nucleic acid-containing cellular components. We have fused spleen cells from such a mouse with the myeloma SP 2/0 and examined the antibodies produced by the resultant cloned hybrid cell lines by using immunoprecipitation and immunofluorescence techniques. Three types of monoclonal antibodies, specific for Sm, DNA, or rRNA, all antigens to which patients who have lupus make antibodies, have been identified. Patient anti-Sm antibody had previously been reported to precipitate five small nuclear ribonucleoproteins that contain U-1, U-2, U-4, U-5, and U-6 RNAs. The monoclonal anti-Sm antibody gives the same immunoprecipitation pattern, providing direct evidence that the Sm antigen resides on all these RNA-protein complexes. Monoclonal anti-Sm antibody will be valuable in deciphering the biological function of these ubiquitous small nuclear RNPs. A simple competition radioimmunoassay using the monoclonal anti-Sm antibody to titer patient sera is also presented. Uses of monoclonal antibodies for the study of autoimmune disease are discussed.

Infectious Tolerance: Human CD25+ Regulatory T Cells Convey Suppressor Activity to Conventional CD4+ T Helper Cells

Abstract: Regulatory CD4 � CD25 � T cells (Treg) are mandatory for maintaining immunologic selftolerance. We demonstrate that the cell-cell contact‐mediated suppression of conventional CD4 � T cells by human CD25 � Treg cells is fixation resistant, independent from membrane-bound TGF- � but requires activation and protein synthesis of CD25 � Treg cells. Coactivation of CD25 � Treg cells with Treg cell‐depleted CD4 � T cells results in anergized CD4 � T cells that in turn inhibit the activation of conventional, freshly isolated CD4 � T helper (Th) cells. This infectious suppressive activity, transferred from CD25 � Treg cells via cell contact, is cell contact‐independent and partially mediated by soluble transforming growth factor (TGF)- � . The induction of suppressive properties in conventional CD4 � Th cells represents a mechanism underlying the phenomenon of infectious tolerance. This explains previously published conflicting data on the role of TGF- � in CD25 � Treg cell‐ induced immunosuppression.

Constitutive class I-restricted exogenous presentation of self antigens in vivo.

Abstract: Ovalbumin (OVA)-specific CD8+ T cells from the T cell receptor-transgenic line OT-I (OT-I cells) were injected into unirradiated transgenic RIP-mOVA mice, which express a membrane-bound form of OVA (mOVA) in the pancreatic islet beta cells and the renal proximal tubular cells. OT-I cells accumulated in the draining lymph nodes (LN) of the kidneys and pancreas and in no other LN. They displayed an activated phenotype and a proportion entered cell cycle. Unilateral nephrectomy 7-13 d before inoculation of OT-I cells into RIP-mOVA mice allowed the injected T cells to home only to the regional LN of the remaining kidney (and pancreas), but when the operation was performed 4 h before injecting the T cells, homing to the LN of the excised kidney was evident. When the bone marrow of RIP-mOVA mice was replaced with one of a major histocompatibility haplotype incapable of presenting OVA to OT-I cells, no homing or activation was detectable. Therefore, OT-I cells were activated by OVA presented by short-lived antigen-presenting cells of bone marrow origin present in the draining LN of OVA-expressing tissue. These results provide the first evidence that tissue-associated "self" antigens can be presented in the context of class I via an exogenous processing pathway. This offers a constitutive mechanism whereby T cells can be primed to antigens that are present in nonlymphoid tissues, which are not normally surveyed by recirculating naive T cells.

Monoclonal antibodies in diagnosis and therapy.

Abstract: Monoclonal antibodies have been applied clinically to the diagnosis and therapy of an array of human disorders, including cancer and infectious diseases, and have been used for the modulation of immune responses. Effective therapy using unmodified monoclonal antibodies has, however, been elusive. Recently, monoclonal antibody-mediated therapy has been revolutionized by advances such as the definition of cell-surface structures on abnormal cells as targets for effective monoclonal antibody action, genetic engineering to create less immunogenic and more effective monoclonal antibodies, and the arming of such antibodies with toxins or radionuclides to enhance their effector function.

Lymphocyte-Mediated Cytotoxicity And Blocking Serum Activity To Tumor Antigens

Abstract: Publisher Summary This chapter reviews the evidence for cell-mediated immune reactions against tumors in animals and man, particularly, the reactions that can lead to destruction of neoplastic cells cultivated in vitro. Various mechanisms by which tumor cells can escape from immunological destruction have been discussed, most notably one involving blocking factors, present in the serum. Findings analogous to those obtained when studying tumor immunity (coexistence of cell-mediated reactivity and blocking serum activity) have been summarized from three other areas (pregnancy, allografting, and chimeras). The studies reviewed in the chapter have given a relatively large amount of evidence for various cell-mediated and humoral immunological reactions against growing tumors, and at least some of the reactions observed in vitro appear to be able to influence tumor growth in vivo .