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.

IgG Placental Transfer in Healthy and Pathological Pregnancies

Abstract: Placental transfer of maternal IgG antibodies to the fetus is an important mechanism that provides protection to the infant while his/her humoral response is inefficient. IgG is the only antibody class that significantly crosses the human placenta. This crossing is mediated by FcRn expressed on syncytiotrophoblast cells. There is evidence that IgG transfer depends on the following: (i) maternal levels of total IgG and specific antibodies, (ii) gestational age, (iii) placental integrity, (iv) IgG subclass, and (v) nature of antigen, being more intense for thymus-dependent ones. These features represent the basis for maternal immunization strategies aimed at protecting newborns against neonatal and infantile infectious diseases. In some situations, such as mothers with primary immunodeficiencies, exogenous IgG acquired by intravenous immunoglobulin therapy crosses the placenta in similar patterns to endogenous immunoglobulins and may also protect the offspring from infections in early life. Inversely, harmful autoantibodies may cross the placenta and cause transitory autoimmune disease in the neonate.

An antigen detected in the blood during the incubation period of serum hepatitis

Abstract: The aim of the following experiments was to provide an objective immunologic criterion for the diagnosis of serum hepatitis, as well as a possible means of screening for carriers of the agent of this disease. An antigen that reacted in the immunodiffusion test with serum from multiply transfused patients was detected in the blood during the incubation period prior to the onset of major chemical or clinical abnormalities. Double blind experiments suggest that this antigen is specific for serum hepatitis virus. Materials and Methods.-Clinical specimens: Sera from cases of transfusion-induced viral hepatitis, which we have collected, were obtained as part of a long-term study involving biweekly follow-up of transfused patients at The New York Hospital. Patients volunteering to participate in this study provided blood samples prior to transfusion and at least biweekly for a period of 6 months or more following transfusion. Test serum: The reference \"antiserum\" used in the majority of the studies to be described, hereinafter referred to as serum S, was obtained from a 24-year-old male patient with hemophilia who has received more than 10,000 units of blood, fresh-frozen plasma, and cryoprecipitate during the course of treatment for bleeding episodes. He has had no episodes of icteric hepatitis, but it was presumed that he had been multiply exposed to the virus or viruses of serum hepatitis. Serum S was chosen for these studies because the patient's multiple exposure was thought to ensure a hyperimmune status. Subsequently, four other sera from multiply transfused patients have been found to react in a manner similar to serum S. For some experiments, the serum was concentrated by ethanol fractionation. To each milliliter of serum to be concentrated, 8 ml of 30% ethanol in 0.1 Ml NaCl, 0.01 M tris(hydroxymethyl)aminomethane (Tris), 0.001 Ml ethylenediaminetetraacetate (EDTA), (pH 7.0 at -7oC) were added. This mixture was held at -70C and lyophilized. The dried globulin fraction was then rehydrated with distilled water to 0.1 the original volume of serum employed. Immunodiffusion technique: Double diffusion in agar gel was done by a micro-Ouchterlony technique.1 Nonspecific precipitation reactions between adjacent wells were eliminated by the use of 0.9% agarose dissolved in a buffer composed of 0.1 M NaCl, 0.01 M Tris (pH 7.6 at 250C), and 0.001 M EDTA containing 1 mg/ml protamine sulfate. Protamine sulfate has been recently suggested as a means of decreasing virus-agar interaction.2 Plates were incubated in a humid atmosphere at room temperature and read daily for 7 days. Strong reactions were evident after overnight incubation, while weaker reactions required 2 or 3 days' incubation and intensified for several days. Clinical chemical methods: Serum glutamic pyruvic transaminase (SGPT) was assayed by a kinetic spectrophotometric method with the Gilford multiple method sample recording spectrophotometer.3 Serum lactic dehydrogenase (LDH) enzymes were assayed by the method of Amador et al.4 with the same instrument. Serum LDH isoenzymes were separated by thin agar gel electrophoresis and quantitated fluorometrically.5 Results.-Demonstration of an antigen appearing in the blood during the incubation period of serum hepatitis: Failure in the past to isolate a causative virus from serum hepatitis could possibly be attributed to the fact that most isolation attempts have been carried out with specimens obtained early in the clinical course of the disease, at what is actually a late stage of the infection due to the

Functional specialization of gut CD103^+ dendritic cells in the regulation of tissue-selective T cell homing

Abstract: Gut-associated lymphoid tissue (GALT) dendritic cells (DCs) display a unique ability to generate CCR9 + α 4 β 7 + gut-tropic CD8 + effector T cells. We demonstrate efficient induction of CCR9 and α 4 β 7 on CD8 + T cells in mesenteric lymph nodes (MLNs) after oral but not intraperitoneal (i.p.) antigen administration indicating differential targeting of DCs via the oral route. In vitro, lamina propria (LP)–derived DCs were more potent than MLN or Peyer's patch DCs in their ability to generate CCR9 + α 4 β 7 + CD8 + T cells. The integrin α chain CD103 ( α E) was expressed on almost all LP DCs, a subset of MLN DCs, but on few splenic DCs. CD103 + MLN DCs were reduced in number in CCR7 − / − mice and, although CD8 + T cells proliferated in the MLNs of CCR7 − / − mice after i.p. but not oral antigen administration, they failed to express CCR9 and had reduced levels of α 4 β 7. Strikingly, although CD103 + and CD103 − MLN DCs were equally potent at inducing CD8 + T cell proliferation and IFN- γ production, only CD103 + DCs were capable of generating gut-tropic CD8 + effector T cells in vitro. Collectively, these results demonstrate a unique function for LP-derived CD103 + MLN DCs in the generation of gut-tropic effector T cells.

Cross-presentation of viral and self antigens by skin-derived CD103 + dendritic cells

Abstract: Skin-derived dendritic cells (DCs) include Langerhans cells, classical dermal DCs and a langerin-positive CD103(+) dermal subset. We examined their involvement in the presentation of skin-associated viral and self antigens. Only the CD103(+) subset efficiently presented antigens of herpes simplex virus type 1 to naive CD8(+) T cells, although all subsets presented these antigens to CD4(+) T cells. This showed that CD103(+) DCs were the migratory subset most efficient at processing viral antigens into the major histocompatibility complex class I pathway, potentially through cross-presentation. This was supported by data showing only CD103(+) DCs efficiently cross-presented skin-derived self antigens. This indicates CD103(+) DCs are the main migratory subtype able to cross-present viral and self antigens, which identifies another level of specialization for skin DCs.

Ubiquitous cell-surface glycoprotein on tumor cells is proliferation-associated receptor for transferrin.

Abstract: A murine monoclonal antibody (OKT9) raised against human leukemic cells binds to a wide variety of leukemia and tumor cell lines and to a minority of leukemia cells taken directly from patients Fetal thymus and liver are strongly reactive as are some normal, immature hemopoietic cells and activated lymphocytes Reactivity with OKT9 appears to correlate with proliferation status in both normal and malignant populations Biochemical analysis indicates that this structure is a approximately equal to 180,000-dalton glycoprotein with two disulfide-bonded subunits of approximately equal to 90,000-daltons Isolation of the transferrin receptor from a T-cell line (MOLT-4) indicates that it also has a dimeric approximately equal to 180,000-dalton structure Radio-labeled transferrin bound to its receptors can be specifically precipitated by the monoclonal OKT9, although the latter does not bind transferrin itself, indicating that the antigenic structure defined by this antibody is likely to be the transferrin receptor