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Polymorphonuclear leukocyte and monocyte chemoattractants produced by human fibroblasts.

Sobel, J D; Gallin, J I
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1979 EN
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The elaboration of leukocyte chemotactic factors by human fibroblasts was studied. 12 lines of normal fibroblasts obtained by skin biopsy and then cultured in vitro produced chemoattractants (assessed by modified Boyden-chamber techniques) for both peripheral blood polymorphonuclear leukocytes and monocytes (obtained by Hypaque-Ficoll and dextran sedimentation). Chemotactic activity was not present performed in fibroblasts, and cycloheximide blocked its elaboration. The chemotactic activity of crude-culture supernate was heat stable (56 degrees C for 30 min), trypsin- and pronase-sensitive, and neuraminidase resistant. Characterization of the chemotactic activity by gel filtration (Sephadex G-75) showed two active fractions, one with mol wt greater than 100,000 and the other less than 10,000. In studies designed to relate these chemotactic factors to collagen, we have confirmed that type I collagen and alpha 1-chain; are chemotactically active for monocytes but not polymorphonuclear leukocytes. However, the chemotactic activity in fibroblast-culture media was media was distinct from collagen in that it attracted neutrophils, it was not precipitated by 25% ammonium sulfate, and it was resistant to collagenase treatment; ascorbic acid...

Big and Little Forms of Osteoclast Activating Factor

Mundy, Gregory R.; Raisz, Lawrence G.; Shapiro, James L.; Bandelin, Janet G.; Turcotte, Robert J.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1977 EN
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We have further characterized osteoclast activating factor (OAF) using a bioassay for bone resorption which utilizes the release of previously incorporated 45Ca from fetal rat long bones in organ culture. When supernatant media from activated leukocyte cultures were concentrated on Amicon PM10 membranes (assigned molecular weight cutoff 10,000 daltons) and chromatographed on Sephadex G-50 columns, the bone-resorbing activity eluted between the molecular weight markers chymotrypsinogen (25,000 daltons) and cytochrome c (12,500 daltons). This peak of biological activity has been called big OAF. When filtrates from the PM10 membranes were concentrated on Amicon UM2 membranes (assigned molecular weight cutoff 1,000 daltons) and chromatographed on Sephadex G-50 columns, some of the biological activity eluted between the molecular weight markers chymotrypsinogen and cytochrome c (big OAF), but there was a separate peak of biological activity which eluted with [3H]proline (140 daltons). This second peak has been called little OAF. Little OAF was eluted from Bio-Gel P6 columns between the molecular weight markers calcitonin (approximately 3,500 daltons) and vitamin B12 (1,330 daltons), but was retained by Spectrapor dialysis tubing (nominal molecular weight cutoff 3...

Nonidentity of Some Simian Virus 40-induced Enzymes with Tumor Antigen

Kit, Saul; Melnick, Joseph L.; Anken, Milton; Dubbs, Del Rose; de Torres, R. A.; Kitahara, Tsunehiro
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1967 EN
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16.55107%
The complement-fixing tumor (T) antigen induced by simian virus 40 (SV40) has been prepared from SV40-infected cell cultures, from infected cell cultures treated at the time of infection with 1-β-d-arabinofuranosylcytosine (ara-C), and from SV40-transformed cells. Upon partial purification, the T antigen exhibited the following properties: it was tightly adsorbed by calcium phosphate gel, it was precipitated by acetic acid at pH 5 or by ammonium sulfate at about 20 to 32% saturation, and it had a molecular weight greater than 250,000, as estimated by Sephadex G-200 gel chromatography. In contrast, deoxycytidylate (dCMP) deaminase, thymidylate (dTMP) kinase, and thymidine (dT) kinase were less strongly bound to calcium phosphate and were not precipitated at pH 5; these enzymes also had much lower molecular weights than the T antigen, as did dihydrofolic (FH2) reductase. Furthermore, higher ammonium sulfate concentrations were required to precipitate dCMP deaminase, dTMP kinase, and FH2 reductase activities than to precipitate the T antigen. Another difference was that the T antigen was not stabilized, but dCMP deaminase, dTMP kinase, and dT kinase, were stabilized, respectively, by dCTP, dTMP, and dT or dTTP. Deoxyribonucleic acid (DNA) polymerase activity resembled the T antigen in adsorption to calcium phosphate...

Isolation of Inhibitory Factor in Raw Milk Whey Active Against Propionibacteria 1

Vedamuthu, E. R.; Washam, C. J.; Reinbold, G. W.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1971 EN
Relevância na Pesquisa
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Preparative isolation of the active component(s) in skim milk whey inhibitory for propionibacteria was made by using (NH4)2SO4 salt fractionation. The crude preparation was further purified by Sephadex G-100 column separation. Disc-gel electrophoresis of the active peak from the Sephadex elution pattern (peak I) showed that this fraction contained almost all of the immune globulin in the column sample. The biologically inactive peaks did not contain any immune globulin. Starch-gel electrophoresis of the active peak revealed the presence of three separate immune globulin fractions. A correlation was also observed between hemolytic reaction of propionibacterial strains and relative resistance to whey inhibition. The investigation showed that one of the immune globulins of milk, pseudoglobulin, was mainly responsible for the suppressive activity of whey.

Density-Gradient and Chromatographic Fraction of Leptospiral Lipase

Berg, Robert N.; Green, Stanley S.; Goldberg, Herbert S.; Blenden, Donald C.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/1969 EN
Relevância na Pesquisa
16.55107%
Fractionation of leptospiral lipase by CsCl density gradients and G-200 Sephadex chromatography yielded five active protein peaks. Two were obtained from the density gradients and three from G-200 Sephadex columns. Esterase activity of these fractions was demonstrated by electrophoretic examination. Several protein bands were visible when disc electrophoresis was performed on the respective fractions. Lipolytic and esterolytic activities were both present, and the overlapping of these activities was discussed.

Lipase of Mucor pusillus1

Somkuti, G. A.; Babel, F. J.; Somkuti, A. C.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1969 EN
Relevância na Pesquisa
16.55107%
Lipase of Mucor pusillus NRRL 2543 was recovered with ammonium sulfate precipitation, gel filtration on Sephadex G-75, and anion-exchange chromatography on diethylaminoethyl-Sephadex A-50. Maximal glycerol ester hydrolase (lipase) activity was observed at pH 5.0 to 5.5 and 50 C when trioctanoin and olive oil were used as substrates. The enzyme also showed esterase activity; it hydrolyzed, with the exception of methyl butyrate, all methyl esters tested. A minimum chain length of six carbons appeared to be a requirement for esterase activity, which was maximal at about pH 5.5 with methyl dodecanoate (C12) as the substrate. Neither the glycerol ester hydrolase (lipase) nor the esterase activity of the enzyme appeared to be affected by thiol group inhibitors, chelating agents, and reducing compounds. On the other hand, hydrolysis of triolein and methyl dodecanoate was arrested to the same extent in the presence of diisopropyl fluorophosphate, which suggested the involvement of serine in the active center of the enzyme. The enzyme remained stable during a 30-day storage at - 10 C.

Enzymatic activities associated with a purified simian virus 40 T antigen-related protein

Tjian, R.; Robbins, A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /02/1979 EN
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16.55107%
A protein antigenically related to the simian virus (SV 40) A gene product has been purified to near homogeneity from cells infected with the adenovirus-SV 40 hybrid virus Ad2+D2 and shown to contain ATPase (ATP phosphohydrolase, EC 3.6.1.3) and protein kinase (ATP:phosphotransferase, EC 2.7.1.37) activity. Both enzymatic activities copurify with the protein through six stages including one gel filtration column, two ion exchange columns, and a heparin affinity column. Analogous fractions from extracts of cells uninfected or infected with adenovirus 2 alone do not contain these enzymatic activities. The D2 hybrid protein resolves into two forms (I and II) during ion exchange chromatography. Form I, the major species (85%) of the D2 hybrid protein, elutes from DEAE-Sephadex in 0.37 M NaCl and is able to catalyze the hydrolysis of ATP to ADP + Pi at a rate of 3 μmol/hr per mg. The remaining 10-15% of the D2 hybrid protein consists of form II which elutes from DEAE-Sephadex in 0.29 M NaCl and is able to hydrolyze ATP as well as to incorporate phosphorus from ATP into either the D2 hybrid protein itself or other protein acceptors such as phosvitin. Although both forms are able to bind DNA, the ATPase activity of form I cosediments with SV 40 DNA more efficiently than does the protein kinase activity of form II during glycerol gradient centrifugation. The ATPase activity of form I is efficiently inhibited by addition of anti-T gamma globulin to the reaction mixture whereas control gamma globulin has no effect. Similarly...

Biosynthesis in vitro of immunoreactive 31,000-dalton corticotropin/β-endorphin-like material by bovine hypothalamus

Liotta, Anthony S.; Gildersleeve, David; Brownstein, Michael J.; Krieger, Dorothy T.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/1979 EN
Relevância na Pesquisa
16.55107%
Enzymatically dispersed bovine hypothalamic or cortical tissue was maintained in culture in the presence of 3H-labeled amino acids. After such incubation, extracts of cells and of media contained 3H-labeled products that were specifically bound by immobilized affinity-purified antisera to corticotropin (ACTH) and β-endorphin. The majority of these products eluted in the void volume (V0) upon Sephadex G-50 gel filtration; minor 3H-labeled products eluted in the regions of the ovine β-lipotropin marker and in fractions having apparent molecular weights of approximately 12,000 and 3800. Sequential use of these immobilized antisera revealed that most of the V0 material contained both ACTH and β-endorphin antigenic determinants within the same molecule(s), whereas retarded material contained only one of the determinants. When this V0 material was rerun on a Sephadex G-75 column, it coeluted with the 31-kilodalton precursor of both ACTH and β-endorphin obtained from a bovine anterior pituitary extract. Thus, the high molecular weight immunoreactive ACTH/β-endorphin-like 3H-labeled product(s) derived from the hypothalamic culture is similar to the pituitary-derived precursor in containing the dual antigenic determinants and in its gel filtration characteristics. In contrast...

Purification of folate binding factor in normal umbilical cord serum.

Kamen, B A; Caston, J D
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/1975 EN
Relevância na Pesquisa
16.55107%
Human umbilical cord serum was found to contain both free folate and folate complexed to a high-molecular weight factor. The complexed folate was bound to a very high affinity binder and was present in concentrations equivalent to as much as 60 ng of 5-methyltetrahydrofolic acid per ml of serum. Acidification of the serum caused disassociation of the folate-binder complex. Released folates were separated from binder by Sephadex gel filtration, zonal centrifugation through sucrose gradients, or adsorption onto activated charcoal. The separated binding factor, either saturated or unsaturated with folate, had a molecular weight of about 40,000 on Sephadex G-200 chromatography. Binding of [3H]pteroylglutamic acid was rapid and, as in the original endogenous folate-binder complex, was essentially irreversible at neutral pH. The affinity and specificity of the binder were examined by competition experiments using [3H]pteroylglutamic acid and nonradioactive folate derivatives. Oxidized folates were bound in preference to reduced derivatives, but only three to four times more unlabeled 5-methyltetrahydrofolic acid than pteroylglutamic acid was required to produce an equal level of competition. The strong affinity for 5-methyltetrahydrofolic acid...

Interconversion of Cyclic Nucleotide-Activated and Cyclic Nucleotide-Independent Forms of a Protein Kinase from Beef Heart

Erlichman, Jack; Hirsch, Allen H.; Rosen, Ora M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1971 EN
Relevância na Pesquisa
16.55107%
A protein kinase activated by cyclic nucleotides was purified from beef heart. Upon exposure to adenosine 3′:5′-cyclic monophosphate (cyclic AMP) during gel filtration on Sephadex G-200, the protein kinase dissociated into a cyclic nucleotide-independent protein kinase and a cyclic nucleotide-binding protein. A similar or identical cyclic nucleotide-independent protein kinase could be obtained in highly purified form by clution from a DEAE-cellulose column with 10-6 M cyclic AMP; the cyclic AMP-binding protein was apparently retained by the resin. The addition of cyclic nucleotide-binding protein to cyclic nucleotide-independent protein kinase resulted in the reappearance of cyclic nucleotide-dependent protein kinase, which could be isolated by filtration on Sephadex G-200 in the absence of cyclic AMP. These results confirm and extend previous suggestions that cyclic nucleotides activate protein kinases by dissociating them from inhibitory, cyclic nucleotide-binding proteins.

Interaction of Eukaryote Initiator Methionyl-tRNA with the Eukaryote Equivalent of Bacterial Elongation Factor T and Guanosine Triphosphate

Richter, Dietmar; Lipmann, Fritz; Tarragó, Adela; Allende, Jorge E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1971 EN
Relevância na Pesquisa
16.55107%
The initiator tRNA, methionyl-tRNAiMet, of yeast and wheat germ forms relatively unstable ternary complexes with their corresponding elongation factors T and GTP. Such complexes can be demonstrated only with fast separation techniques such as Sephadex G-50 and Millipore filtration, but not with the slow Sephadex G-100 method, although both techniques yield stable ternary complexes with all other aminoacyl-tRNAs, including the internal Met-tRNAmMet. To bind yeast-initiating Met-tRNAiMet to ribosomes, initiation factors present in a ribosomal wash fraction from yeast are needed.

A purified fraction containing RNA polymerase I that can accurately transcribe rat ribosomal RNA gene.

Kurl, R N; Rothblum, L I; Jacob, S T
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/1984 EN
Relevância na Pesquisa
16.55107%
Transcription of a cloned rat rDNA containing the transcription initiation region was studied using purified fractions derived from whole cell extract. The cell extract obtained from rat mammary adenocarcinoma cells was fractionated successively on DEAE-Sephadex and heparin-Sepharose columns. The fractions eluted by 175 mM (NH4)2SO4 (DE-B) from the DEAE-Sephadex column and those eluting with RNA polymerase I on the subsequent heparin-Sepharose column (HS-B) were used in a run-off transcription assay using Xho I-cleaved cloned rat rDNA. Both fractions that contained greater than 90% of the RNA polymerase I activity produced the anticipated 635-nucleotide-long transcript. Fractionation of fraction DE-B on a phosphocellulose column also resulted in a RNA polymerase I-containing complex that, by itself, could transcribe the rDNA accurately. The major polypeptides obtained after NaDodSO4/PAGE of fraction HS-B had Mr values of 190,000, 120,000, 65,000, 42,000, and 25,000, corresponding to the major subunits of RNA polymerase I. Purified nuclear RNA polymerase I did not produce the correct transcript. These studies have shown that a purified fraction containing RNA polymerase I from whole cells can support accurate transcription of rDNA.

The Aggregation States of Phytochrome from Etiolated Rye and Oat Seedings

Correll, David L.; Edwards, John L.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1970 EN
Relevância na Pesquisa
16.55107%
Initial extracts from etiolated plants contained two aggregates of phytochrome. A major fraction was almost excluded by Sephadex G-200 and was within the fractionation range of Sepharose 4 B. A minor fraction was within the fractionation range of Sephadex G-200. Modifications of a previous isolation procedure which allowed retention of this aggregation state are reported. With respect to gel filtration, the major fraction of phytochrome from oat and rye seedlings was identical. The aggregates of rye and oat phytochrome were also separated by diethylaminoethyl cellulose chromatography.

Uroporphyrinogen I synthase from human erythrocytes: separation, purification, and properties of isoenzymes.

Miyagi, K; Kaneshima, M; Kawakami, J; Nakada, F; Petryka, Z J; Watson, C J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1979 EN
Relevância na Pesquisa
16.55107%
Uroporphyrinogen I synthase [porphobilinogen ammonia-lyase (polymerizing), EC 4.3.1.8] from human erythrocytes was separated into two active protein peaks (A and B on DEAE-cellulose, by ammonium sulfate fractionation, on Sephadex G-100, and on DEAE-Sephadex A-50 with a NaCl gradient. The final purification was 613 and 743 times for A and B, respectively. The corresponding yields were 2.2 and 3.4% Fraction A was separated further into two (A1 and A2) active protein bands and fraction B into three (B1, B2, and B3) on analytical polyacrylamide disc gel electrophoresis. Bands A1 and A2 were identical with B1 and B2; B3 represented a third isoenzyme. Molecular weights (mean +/- SEM), measured by gel filtration and sodium dodecyl sulfate/polyacrylamide gel electrophoresis, were 38,000 +/- 1000 for B1 and 40,000 +/- 1000 for B2 and B3. Isoelectric focusing on 4% polyacrylamide gel separated both fractions A and B into three active protein bands. Maximal activity of the enzyme was found in gel cuts (5-mm) at pH 5.6 for both fractions A and B.

Purification, Composition, and Serological Characterization of Histoplasmin—H and M Antigens

Bradley, Georgia; Pine, Leo; Reeves, Michael W.; Moss, C. Wayne
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1974 EN
Relevância na Pesquisa
16.55107%
To obtain purified H and M antigens suitable as primary standards in the serological diagnosis of histoplasmosis by agar gel double-diffusion tests, H and M reactive components of histoplasmin were fractionated by column chromatography by using Sephadex G-100, Sephadex G-200, and diethylaminoethyl cellulose. Six fractions from diethylaminoethyl cellulose were reactive in agar gel double-diffusion, complement fixation, and capillary precipitin tests. When examined by electrophoresis on acrylamide gel, one M antigen (fraction 2, molecular weight greater than 200,000) and two H antigens (fractions 5 and 6, molecular weight greater than 200,000) each gave essentially a single protein band. In agar gel double-diffusion and complement fixation tests with sera from patients with proven cases of histoplasmosis, blastomycosis, or coccidioidomycosis, these two fractions of H antigen and the one of M antigen reacted only with sera from proven or suspect cases of histoplasmosis and showed reactivity with those sera known to contain only the anti-H or anti-M antibody, respectively. Fraction 2 (M antigen) and fractions 5 and 6 (H antigens) had carbohydrate-to-protein ratios of 1.60, 0.77 and 0.78, respectively. Both antigens contained galactose...

Partial purification and characterization of RTG-2 fish cell interferon.

de Sena, J; Rio, G J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1975 EN
Relevância na Pesquisa
16.55107%
Interferon produced by rainbow trout gonadal cells (RTG-2) was partially purified. The physical, chemical, and biological properties of this in vitro produced fish cell interferon were studied. Purification was achieved by ultracentrifugation, molecular sieve gel chromatography, ion exchange chromatography, and polyacrylamide gel electrophoresis. The isoelectric point of RTG-2 interferon, as determined by CM-Sephadex (C-50) chromatography, was 7.1. Filtration through Sephadex G-150 showed that RTG-2 interferon had a molecular weight of 94,000. The partially purified material was not sedimented at 105,000 times g for 2 h at 4 C. The fish cell interferon was non-dialyzable and exhibited heat and pH stability. The partially purified material was inactivated by treatment with trypsin or 2-mercaptoethanol, but was resistant to treatment with deoxyribonuclease or ribonuclease. RTG-2 interferon which was induced by infectious pancreatic necrosis virus exhibited antiviral activity against challenge with infectious hematopoietic necrosis virus or infectious pancreatic necrosis virus. Partially purified RTG-2 interferon exhibited greater species specificity than the crude material.

Chemical composition and immunological specificity of cell wall polysaccharide group antigens of streptococcal groups P and U.

Wessman, G E
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1975 EN
Relevância na Pesquisa
16.55107%
The group antigens of streptococcal groups P and U were extracted with formamide and purified on diethylaminoethyl-Sephadex A-25 and Sephadex G-200. The antigens were shown to be polysaccharides located in the cell walls of the organisms. In a precipitin test, the P and U group antigens did not cross-react with homologous sera of each other, nor with specific antiserum of the group antigen of group E streptococci. The polysaccharide comprising the group P antigen contained rhamnose, glucose, galactose, glucosamine, and galactosamine; the group U antigen was similar in composition but lacked galactosamine and contained more galactose.

Molecular weight and other characteristics of mycobacterial growth inhibitory factor produced by spleen cells obtained from mice immunized with viable attenuated mycobacterial cells.

Cahall, D L; Youmans, G P
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1975 EN
Relevância na Pesquisa
16.55107%
Exposure of mycobacterial growth inhibitory factor (MycoIF) to trypsin, chymotrypsin, or neuraminidase decrease its ability to produce intracellular inhibition of mycobacterial growth within macrophages, suggesting that MycoIF was a glycoprotein. MycoIF was unaffected by deoxyribonuclease or ribonuclease. Supernatant fluids from antigenically stimulated H37Ra-immunized mouse spleen cells exposed to puromycin were unable to produce significant intracellular inhibition. This indicated that the presence of MycoIF activity in supernatant fluids required protein synthesis. The filtration of MycoIF-containing supernatant fluids on Sephadex G-150 demonstrated that significant MycoIF activity appeared only in those fractions which eluted on the downward side of the serum albumin peak. Based on protein standards filtered through the Sephadex gel, the molecular weight of MycoIF was calculated to be between 20,000 and 35,000. These calculations assumed that MycoIF is a globular protein. Attempts to purify MycoIF by anion exchange chromatography (diethylaminoethylcellulose) was not successful.

Isolation of a factor causing morphological changes of chinese hamster ovary cells from the culture filtrate of Vibrio parahaemolyticus.

Honda, T; Shimizu, M; Takeda, Y; Miwatani, T
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1976 EN
Relevância na Pesquisa
16.55107%
A factor changing Chinese hamster ovary cells from an oval to a spindle shape was isolated from the culture filtrate of Vibrio parahaemolyticus. It was partially purified by successive column chromatographies on diethylaminoethylcellulose, diethylaminoethyl-Sephadex A-25, hydroxylapatite, and Sephadex G-200. This factor was separated from thermostabl direct hemolysin and was heat labile.

Isolation and Characterization of Neisseria meningitidis Groups A, C, X, and Y Polysaccharide Antigens

Robinson, John A.; Apicella, Michael A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1970 EN
Relevância na Pesquisa
16.55107%
To prepare Neisseria meningitidis groups A, C, X, and Y polysaccharide antigens, culture supernatant fluids were subjected to serial processes of salt precipitation, alkaline hydrolysis, ethyl alcohol precipitation, and Sephadex G-200 chromatography. This method resulted in the isolation of large quantities of group antigens. All are acidic polysaccharides, the group C antigen being a polymer of n-acetyl neuraminic acid. Thiobarbituric acid assay failed to reveal sialic acids in the other group antigens. Protein was undetectable by absorption at 280 nm or by Folin analysis. These antigens are of similar molecular size, the majority of which are excluded by Sephadex G-200. They migrate in the upper one-third of sucrose density gradients and are retained by 5% acrylamide gel. All are highly group-specific and react only with homologous hyperimmune antisera in hemagglutination, complement fixation, and immunodiffusion systems. As little as 0.03 μmoles of n-acetyl neuraminic acid in group C antigen inhibits the hemagglutination of group C-sensitized red cells. All antigens are immunogenic in rabbits. These techniques afford a simplified method for the production of relatively large yields of highly specific group antigens which participate in multiple immunologic systems.