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.

Clonotypic structures involved in antigen-specific human T cell function. Relationship to the T3 molecular complex.

Abstract: Monoclonal antibodies were produced against a human cytotoxic T cell clone, CT8III (specificity: HLA-A3), with the view of defining clonally restricted (clonotypic) surface molecules involved in its antigen recognition function. Two individual antibodies, termed anti-Ti1A and anti-Ti1B, reacted exclusively with the CT8III clone when tested on a panel of 80 additional clones from the same donor, resting or activated T cells, B cells, macrophages, thymocytes, or other hematopoietic cells. More importantly, the two antibodies inhibited cell-mediated killing and antigen-specific proliferation of the CT8III clone but did not affect the functions of any other clone tested. This inhibition was not secondary to generalized abrogation of the CT8III clone's function, because interleukin 2 responsiveness was enhanced. To examine the relationship of the structures defined by anti-clonotypic antibodies with known T cell surface molecules, antibody-induced modulation studies and competitive binding assays were performed. The results indicated that the clonotypic structures were associated with, but distinct from, the 20,000-mol wt T3 molecule expressed on all mature T lymphocytes. Moreover, in contrast to anti-T3, anti-Ti1A and anti-Ti1B each immunoprecipitated two molecules of 49,000 and 43,000-mol wt from 131I-labeled CT8III cells under reducing conditions. The development of monoclonal antibodies to such polymorphic T cell surface structures should provide important probes to further define the surface receptor for antigen.

Immunological surveillance against altered self components by sensitised T lymphocytes in lymphocytic choriomeningitis.

Abstract: THE cytotoxic activity1,2 of immune thymus-derived lymphocytes (T cells) for 51Cr-labelled fibroblasts, or macrophages infected with lymphocytic choriomeningitis (LCM) virus is restricted by the H-2 gene complex3,4. Specific lysis of LCM-infected monolayer cultures occurs only when targets and overlaying, sensitised T cells share at least one set of H-2 antigenic specificities.

Immunological studies concerning the nephritis of systemic lupus erythematosus

Abstract: Antibodies were eluted from the isolated glomeruli prepared from the kidneys of 10 patients with the nephritis of systemic lupus erythematosus. Antibodies reacting primarily with buffer extracts of nuclei were eluted by acid treatment, and antibodies reacting mainly with DNA and nucleoprotein were eluted with deoxyribonuclease. Quantitative immunochemical studies revealed a high concentration of antinuclear antibody per milligram of γ-globulin in glomerular eluates compared with that in the corresponding serums. The γ-globulin of two eluates was found to consist predominantly of antinucleoprotein antibody. The selective elution of antinuclear antibodies was also indicated by the absence of other serum antibodies in the eluates. DNA antigen was demonstrated in the glomeruli of two kidneys with nephritis by means of isolated anti-DNA antibody labeled with fluorescein. In one of these cases, anti-DNA antibodies were also found concentrated in the glomeruli and, in the second, circulating anti-DNA antibodies were demonstrated in the patient's serum. The immunochemical evidence for the high specific activity of antinuclear antibodies and the association of DNA antigen with DNA antibody in glomeruli add further support for the antigen-antibody complex hypothesis for renal injury in systemic lupus erythematosus.

The common mucosal immune system and current strategies for induction of immune responses in external secretions

Abstract: The selective induction of antibodies in external secretions is desirable for the prevention of various systemic as well as predominantly mucosa-restricted infections. An enormous surface area of mucosal membranes is protected primarily by antibodies that belong, in many species, to the IgA isotype. Such antibodies are produced locally by large numbers of IgA-containing plasma cells distributed in subepithelial spaces of mucosal membranes and in the stroma of secretory glands. In humans and in some animal species, plasma-derived IgA antibodies do not enter external secretions in significant quantities and systemically administered preformed IgA antibodies would be of little use for passive immunization. Systemic administration of microbial antigens may boost an effective S-IgA immune response only in a situation whereby an immunized individual had previously encountered the same antigen by the mucosal route. Local injection of antigen in the vicinity of secretory glands is usually accompanied by an undesirable concomitant systemic response and frequently requires the addition of adjuvants that are unacceptable for administration in humans. Immunization routes that involve ingestion or possibly inhalation of antigens lead to the induction of not only local but also generalized immune responses manifested by the parallel appearance of S-Iga antibodies to ingested or inhaled antigens in secretions of glands distant from the site of immunization. Based on extensive studies in animal models as well as in humans, convincing evidence is available that antigen-sensitized and IgA-committed precursors of plasma cells from GALT are disseminated to the gut, other mucosa-associated tissues, and exocrine glands. However, due to the limited absorption of desired antigens from the gut lumen of orally immunized individuals, repeated large doses of antigens are required for an effective S-IgA response. Novel antigen delivery systems for the stimulation of such responses are currently being examined in several laboratories. Live attenuated or genetically manipulated bacteria expressing other microbial antigens have also been used for selective colonization of gut-associated lymphoid tissues. Unique antigen packaging and the use of adjuvants suitable for oral administration hold promise for an efficient antigen delivery to critical tissues in the intestine and deserve extensive exploration. The oral immunization route appears to have many advantages over systemic immunization.(ABSTRACT TRUNCATED AT 400 WORDS)

A monoclonal antibody reactive with human peripheral blood monocytes.

Abstract: A monoclonal antibody directed at a determinant on human peripheral blood monocytes was produced and characterized. This hybridoma antibody, termed OKM1, was reactive by indirect immunofluorescence and complement- (C) mediated lysis with adherent mononuclear cells. OKM1 was unreactive with lymphocytes, thymocytes, lymphoblastoid cell lines, and tumor cells of the T or B cell lineage. In contrast, acute myelomonocytic leukemia cells and granulocytes were reactive with the antibody. Pretreatment of peripheral blood mononuclear cells with OKM1 and C before culture with soluble antigens totally abolished their antigen-induced proliferative response. This function was restored by addition of 1% adherent cells. These findings provided additional support for the notion that OKM1 was reactive with monocytes. In addition, OKM1 appeared to define two distinct populations of monocytes; an adherent population of large cells bearing surface Ia determinants and a nonadherent population of small, Ia-negative cells. These OKM1+ Ia- cells were found to be a contaminant of most fractionated mononuclear cell subsets including the E-SIg-Null cell population.