Precipitin Tests: Serologic tests in which a positive reaction manifested by visible CHEMICAL PRECIPITATION occurs when a soluble ANTIGEN reacts with its precipitins, i.e., ANTIBODIES that can form a precipitate.Farmer's Lung: A form of alveolitis or pneumonitis due to an acquired hypersensitivity to inhaled antigens associated with farm environment. Antigens in the farm dust are commonly from bacteria actinomycetes (SACCHAROPOLYSPORA and THERMOACTINOMYCES), fungi, and animal proteins in the soil, straw, crops, pelts, serum, and excreta.Immunodiffusion: Technique involving the diffusion of antigen or antibody through a semisolid medium, usually agar or agarose gel, with the result being a precipitin reaction.Precipitins: Antibodies which elicit IMMUNOPRECIPITATION when combined with antigen.Complement Fixation Tests: Serologic tests based on inactivation of complement by the antigen-antibody complex (stage 1). Binding of free complement can be visualized by addition of a second antigen-antibody system such as red cells and appropriate red cell antibody (hemolysin) requiring complement for its completion (stage 2). Failure of the red cells to lyse indicates that a specific antigen-antibody reaction has taken place in stage 1. If red cells lyse, free complement is present indicating no antigen-antibody reaction occurred in stage 1.Immunoelectrophoresis: A technique that combines protein electrophoresis and double immunodiffusion. In this procedure proteins are first separated by gel electrophoresis (usually agarose), then made visible by immunodiffusion of specific antibodies. A distinct elliptical precipitin arc results for each protein detectable by the antisera.Immune Sera: Serum that contains antibodies. It is obtained from an animal that has been immunized either by ANTIGEN injection or infection with microorganisms containing the antigen.Streptococcus: A genus of gram-positive, coccoid bacteria whose organisms occur in pairs or chains. No endospores are produced. Many species exist as commensals or parasites on man or animals with some being highly pathogenic. A few species are saprophytes and occur in the natural environment.Antigens: Substances that are recognized by the immune system and induce an immune reaction.Serotyping: Process of determining and distinguishing species of bacteria or viruses based on antigens they share.Antigens, Bacterial: Substances elaborated by bacteria that have antigenic activity.Counterimmunoelectrophoresis: Immunoelectrophoresis in which immunoprecipitation occurs when antigen at the cathode is caused to migrate in an electric field through a suitable medium of diffusion against a stream of antibody migrating from the anode as a result of endosmotic flow.Coccidioides: A mitosporic fungal genus which causes COCCIDIOIDOMYCOSIS.Antigens, Fungal: Substances of fungal origin that have antigenic activity.Antibodies, Fungal: Immunoglobulins produced in a response to FUNGAL ANTIGENS.Coccidioidomycosis: Infection with a fungus of the genus COCCIDIOIDES, endemic to the SOUTHWESTERN UNITED STATES. It is sometimes called valley fever but should not be confused with RIFT VALLEY FEVER. Infection is caused by inhalation of airborne, fungal particles known as arthroconidia, a form of FUNGAL SPORES. A primary form is an acute, benign, self-limited respiratory infection. A secondary form is a virulent, severe, chronic, progressive granulomatous disease with systemic involvement. It can be detected by use of COCCIDIOIDIN.Antigen-Antibody Reactions: The processes triggered by interactions of ANTIBODIES with their ANTIGENS.Alveolitis, Extrinsic Allergic: A common interstitial lung disease caused by hypersensitivity reactions of PULMONARY ALVEOLI after inhalation of and sensitization to environmental antigens of microbial, animal, or chemical sources. The disease is characterized by lymphocytic alveolitis and granulomatous pneumonitis.Coccidioidin: A sterile solution containing the by-products of growth products of COCCIDIOIDES IMMITIS, injected intracutaneously as a test for COCCIDIOIDOMYCOSIS.Immunoelectrophoresis, Two-Dimensional: Immunoelectrophoresis in which a second electrophoretic transport is performed on the initially separated antigen fragments into an antibody-containing medium in a direction perpendicular to the first electrophoresis.Cross Reactions: Serological reactions in which an antiserum against one antigen reacts with a non-identical but closely related antigen.Aspergillosis, Allergic Bronchopulmonary: Hypersensitivity reaction (ALLERGIC REACTION) to fungus ASPERGILLUS in an individual with long-standing BRONCHIAL ASTHMA. It is characterized by pulmonary infiltrates, EOSINOPHILIA, elevated serum IMMUNOGLOBULIN E, and skin reactivity to Aspergillus antigen.Micromonosporaceae: A family of gram-positive, saprophytic bacteria occurring in soil and aquatic environments.Immunochemistry: Field of chemistry that pertains to immunological phenomena and the study of chemical reactions related to antigen stimulation of tissues. It includes physicochemical interactions between antigens and antibodies.Encephalitis, Arbovirus: Infections of the brain caused by arthropod-borne viruses (i.e., arboviruses) primarily from the families TOGAVIRIDAE; FLAVIVIRIDAE; BUNYAVIRIDAE; REOVIRIDAE; and RHABDOVIRIDAE. Life cycles of these viruses are characterized by ZOONOSES, with birds and lower mammals serving as intermediate hosts. The virus is transmitted to humans by the bite of mosquitoes (CULICIDAE) or TICKS. Clinical manifestations include fever, headache, alterations of mentation, focal neurologic deficits, and COMA. (From Clin Microbiol Rev 1994 Jan;7(1):89-116; Walton, Brain's Diseases of the Nervous System, 10th ed, p321)Chemical Precipitation: The formation of a solid in a solution as a result of a chemical reaction or the aggregation of soluble substances into complexes large enough to fall out of solution.Agglutinins: Substances, usually of biological origin, that cause cells or other organic particles to aggregate and stick to each other. They include those ANTIBODIES which cause aggregation or agglutination of particulate or insoluble ANTIGENS.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.HistoplasminAntibodies: Immunoglobulin molecules having a specific amino acid sequence by virtue of which they interact only with the ANTIGEN (or a very similar shape) that induced their synthesis in cells of the lymphoid series (especially PLASMA CELLS).Convalescence: The period of recovery following an illness.Encephalitis Viruses: A collection of single-stranded RNA viruses scattered across the Bunyaviridae, Flaviviridae, and Togaviridae families whose common property is the ability to induce encephalitic conditions in infected hosts.Trichloroacetic Acid: A strong acid used as a protein precipitant in clinical chemistry and also as a caustic for removing warts.Bird Fancier's Lung: A form of alveolitis or pneumonitis due to an acquired hypersensitivity to inhaled avian antigens, usually proteins in the dust of bird feathers and droppings.Hemagglutination Tests: Sensitive tests to measure certain antigens, antibodies, or viruses, using their ability to agglutinate certain erythrocytes. (From Stedman, 26th ed)Agglutination Tests: Tests that are dependent on the clumping of cells, microorganisms, or particles when mixed with specific antiserum. (From Stedman, 26th ed)Rhamnose: A methylpentose whose L- isomer is found naturally in many plant glycosides and some gram-negative bacterial lipopolysaccharides.Polysaccharides, Bacterial: Polysaccharides found in bacteria and in capsules thereof.gamma-Globulins: Serum globulins that migrate to the gamma region (most positively charged) upon ELECTROPHORESIS. At one time, gamma-globulins came to be used as a synonym for immunoglobulins since most immunoglobulins are gamma globulins and conversely most gamma globulins are immunoglobulins. But since some immunoglobulins exhibit an alpha or beta electrophoretic mobility, that usage is in decline.Serum Albumin, Radio-Iodinated: Normal human serum albumin mildly iodinated with radioactive iodine (131-I) which has a half-life of 8 days, and emits beta and gamma rays. It is used as a diagnostic aid in blood volume determination. (from Merck Index, 11th ed)Methylmannosides: Mannosides formed by the reaction of the hydroxyl group on the anomeric carbon atom of mannose with methyl alcohol. They include both alpha- and beta-methylmannosides.Epitopes: Sites on an antigen that interact with specific antibodies.Carbohydrates: The largest class of organic compounds, including STARCH; GLYCOGEN; CELLULOSE; POLYSACCHARIDES; and simple MONOSACCHARIDES. Carbohydrates are composed of carbon, hydrogen, and oxygen in a ratio of Cn(H2O)n.Methods: A series of steps taken in order to conduct research.Chromatography, Gel: Chromatography on non-ionic gels without regard to the mechanism of solute discrimination.Aspergillus fumigatus: A species of imperfect fungi from which the antibiotic fumigatin is obtained. Its spores may cause respiratory infection in birds and mammals.Agricultural Workers' Diseases: Diseases in persons engaged in cultivating and tilling soil, growing plants, harvesting crops, raising livestock, or otherwise engaged in husbandry and farming. The diseases are not restricted to farmers in the sense of those who perform conventional farm chores: the heading applies also to those engaged in the individual activities named above, as in those only gathering harvest or in those only dusting crops.Actinomycosis: Infections with bacteria of the genus ACTINOMYCES.Molecular Weight: The sum of the weight of all the atoms in a molecule.Comb and Wattles: Fleshy and reddish outgrowth of skin tissue found on top of the head, attached to the sides of the head, and hanging from the mandible of birds such as turkeys and chickens.Agar: A complex sulfated polymer of galactose units, extracted from Gelidium cartilagineum, Gracilaria confervoides, and related red algae. It is used as a gel in the preparation of solid culture media for microorganisms, as a bulk laxative, in making emulsions, and as a supporting medium for immunodiffusion and immunoelectrophoresis.Blastomycosis: A fungal infection that may appear in two forms: 1, a primary lesion characterized by the formation of a small cutaneous nodule and small nodules along the lymphatics that may heal within several months; and 2, chronic granulomatous lesions characterized by thick crusts, warty growths, and unusual vascularity and infection in the middle or upper lobes of the lung.Food Industry: The industry concerned with processing, preparing, preserving, distributing, and serving of foods and beverages.Amino Acids: Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.Radioimmunoprecipitation Assay: Sensitive assay using radiolabeled ANTIGENS to detect specific ANTIBODIES in SERUM. The antigens are allowed to react with the serum and then precipitated using a special reagent such as PROTEIN A sepharose beads. The bound radiolabeled immunoprecipitate is then commonly analyzed by gel electrophoresis.Evaluation Studies as Topic: Studies determining the effectiveness or value of processes, personnel, and equipment, or the material on conducting such studies. For drugs and devices, CLINICAL TRIALS AS TOPIC; DRUG EVALUATION; and DRUG EVALUATION, PRECLINICAL are available.Potassium Iodide: An inorganic compound that is used as a source of iodine in thyrotoxic crisis and in the preparation of thyrotoxic patients for thyroidectomy. (From Dorland, 27th ed)Chromatography, Ion Exchange: Separation technique in which the stationary phase consists of ion exchange resins. The resins contain loosely held small ions that easily exchange places with other small ions of like charge present in solutions washed over the resins.Skin Tests: Epicutaneous or intradermal application of a sensitizer for demonstration of either delayed or immediate hypersensitivity. Used in diagnosis of hypersensitivity or as a test for cellular immunity.Chemistry: A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.Chemical Phenomena: The composition, conformation, and properties of atoms and molecules, and their reaction and interaction processes.Antibodies, Bacterial: Immunoglobulins produced in a response to BACTERIAL ANTIGENS.Hemagglutination Inhibition Tests: Serologic tests in which a known quantity of antigen is added to the serum prior to the addition of a red cell suspension. Reaction result is expressed as the smallest amount of antigen which causes complete inhibition of hemagglutination.Antigen-Antibody Complex: The complex formed by the binding of antigen and antibody molecules. The deposition of large antigen-antibody complexes leading to tissue damage causes IMMUNE COMPLEX DISEASES.Isoelectric Point: The pH in solutions of proteins and related compounds at which the dipolar ions are at a maximum.Electrophoresis: An electrochemical process in which macromolecules or colloidal particles with a net electric charge migrate in a solution under the influence of an electric current.