scholarly journals The action of pepsin on porcine immunoglobulin M and its effect on biological activity

1980 ◽  
Vol 191 (1) ◽  
pp. 183-191 ◽  
Author(s):  
D Beale ◽  
J K Fazakerley
Keyword(s):  
Biological Activity ◽  
Random Process ◽  
Complement Fixation ◽  
Immunoglobulin M ◽  
Structural Studies

Treatment of porcine immunoglobulin M (IgM) with pepsin at pH 4.6 and 37 degrees C was found to gradually remove Fab arms and Cmicro2 domains over a period of 18h. Structural studies failed to find any other change. The main products can therefore be regarded as IgM-like molecules with limited numbers of Fab arms and Cmicro2 domains. Results indicated that this removal of Fab arms is probably a random process. As the average number of Fab arms per molecule was decreased the ability to agglutinate Salmonella oranienburg (mt-H) gradually diminished. Complement fixation by the complexes however, decreased rapidly, and became negligible when the average number of Fab arms was four. This was confirmed by using a preparation containing mainly molecules with three or four Fab arms. The overall results showed that molecules with three or four Fab arms can agglutinate Salmonella but that these complexes do not fix complement. Molecules with five arms probably behave like those with four. Complexes formed by molecules with six arms fix complement quite efficiently. Possible explanations for these results are discussed.

CHEMISTRY OF GONADOTROPHINS IN RELATION TO THEIR ANTIGENIC PROPERTIES

1969 ◽  
Vol 62 (1_Suppl) ◽  
pp. S13-S30 ◽  
Author(s):  
W. R. Butt
Keyword(s):  
Biological Activity ◽  
Guinea Pigs ◽  
Complement Fixation ◽  
Neuraminic Acid ◽  
Fixation Technique ◽  
Immunological Activity ◽  
Antigenic Properties ◽  
Specific Antisera ◽  
Structural Differences

ABSTRACT Several chemical differences between FSH, LH and HCG have been reported: thus LH and HCG are richer in proline than FSH and FSH and HCG contain more N-acetyl neuraminic acid than LH. Sub-units of LH are formed by treatment with urea, guanidine or acid. HCG also may contain two sub-units. The sub-units from LH are biologically inert but retain their immunological activity: biological activity is restored when the sub-units are incubated together. There is much evidence from chemical and enzymic reactions that antigenic groups are distinct from those parts of the molecule essential for biological activity. N-acetyl neuraminic acid and probably other carbohydrates in FSH and HCG are not involved in immunological activity but are necessary for biological activity. Histidine, methionine and possibly cysteine appear to be essential for biological but not immunological activity of FSH, while tryptophan and possibly tyrosine are not essential for either. A few highly specific antisera to gonadotrophins have been prepared in rabbits and guinea pigs to crude antigens: there is no evidence that purified antigens are more likely to produce specific antisera. Differences in the immunological reactivities of urinary compared with pituitary gonadotrophins have been observed both by radioimmunoassay and by the complement fixation technique. The latter may be particularly useful for detecting structural differences in the hormones.

Synthesis, structural studies and biological activity of novel Cu(II) complexes with thiourea derivatives of 4-azatricyclo[5.2.1.0 2,6 ]dec-8-ene-3,5-dione

2017 ◽  
Vol 176 ◽  
pp. 8-16 ◽  
Author(s):  
Aleksandra Drzewiecka-Antonik ◽  
Paweł Rejmak ◽  
Marcin T. Klepka ◽  
Anna Wolska ◽  
Piotr Pietrzyk ◽  
...  
Keyword(s):  
Biological Activity ◽  
Structural Studies ◽  
Thiourea Derivatives ◽  
Derivatives Of

Structural Studies and Biological Activity of Plant Triterpenoids from the Thalictrum Genus

2005 ◽  
Vol 41 (2) ◽  
pp. 117-140 ◽  
Author(s):  
V. I. Lutskii ◽  
A. S. Gromova ◽  
E. A. Khamidullina ◽  
N. L. Owen
Keyword(s):  
Biological Activity ◽  
Structural Studies

scholarly journals COMPLEMENT FIXATION BY A TWO-COMPONENT ANTIBODY SYSTEM: IMMUNOGLOBULIN G AND IMMUNOGLOBULIN M ANTI-GLOBULIN (RHEUMATOID FACTOR)

1970 ◽  
Vol 132 (4) ◽  
pp. 673-693 ◽  
Author(s):  
Frank R. Schmid ◽  
Ivan M. Roitt ◽  
Maria J. Rocha
Keyword(s):  
Rheumatoid Factor ◽  
Complement Fixation ◽  
Direct Interaction ◽  
Fluid Phase ◽  
Kinetic Studies ◽  
Immunoglobulin M ◽  
Inhibitory Potency ◽  
Cell Agglutination ◽  
Igm Rheumatoid Factor ◽  
Rabbit Igg

Complement-mediated lysis of sheep erythrocytes coated with optimal concentrations of rabbit IgG hemolysin was inhibited by euglobulin fractions from the sera of patients with seropositive rheumatoid arthritis. That this was due to direct interaction with the IgG coat on the red cell rather than a nonspecific reaction with complement in the fluid phase was confirmed by controls using cells coated with IgM hemolysin. The inhibitory activity was recovered in purified IgM rheumatoid factor preparations and could be absorbed out with insoluble aggregated human IgG. The inhibitory potency of the rheumatoid factors correlated well with their sheep cell agglutination titers. Inhibition was not the result of physical aggregation of the erythrocytes by rheumatoid factor. Kinetic studies were consistent with the view that rheumatoid factor displaces C1q from its binding to IgG. Paradoxically, at suboptimal sensitizing concentrations of IgG hemolysin, rheumatoid factor enhances the fixation of complement. These results can be interpreted on the basis of the blockage of complement fixation by IgG and its replacement by a relatively weak direct fixation by the IgM rheumatoid factor. Thus, the interaction of RF with IgG generates only a limited ability to fix complement which, when contrasted with the fixation at suboptimal concentrations of IgG hemolysin alone, appears as net enhancement; when this is contrasted with fixation occurring with optimal concentrations of IgG, it appears as net inhibition.

Synthesis, structural studies and biological activity of new Cu(II) complexes with acetyl derivatives of 7-hydroxy-4-methylcoumarin

2015 ◽  
Vol 145 ◽  
pp. 94-100 ◽  
Author(s):  
Marcin T. Klepka ◽  
Aleksandra Drzewiecka-Antonik ◽  
Anna Wolska ◽  
Paweł Rejmak ◽  
Kinga Ostrowska ◽  
...  
Keyword(s):  
Biological Activity ◽  
Structural Studies ◽  
Derivatives Of

scholarly journals Sensitive Enzyme-Linked Immunosorbent Assay for Detection of Antibodies Against Typhus Rickettsiae, Rickettsia prowazekii and Rickettsia typhi

1977 ◽  
Vol 6 (2) ◽  
pp. 101-110
Author(s):  
Sidney Halle ◽  
Gregory A. Dasch ◽  
Emilio Weiss
Keyword(s):  
Immunosorbent Assay ◽  
Complement Fixation ◽  
Differential Susceptibility ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Rickettsia Prowazekii ◽  
Rickettsia Typhi ◽  
Titration Curves ◽  
Ether Extraction ◽  
Human Sera

An enzyme-linked immunosorbent assay (ELISA) has been developed for the titration of rickettsial antibodies in human and animal sera. Two preparations of soluble typhus-group antigens were obtained from Rickettsia typhi and Rickettsia prowazekii by ether extraction: a standard antigen from infected yolk sacs (YS antigen) and one free of yolk sac contaminants from Renografin-purified rickettsiae (PR antigen). Rabbit, mouse, and guinea pig sera were obtained by immunization with viable purified R. typhi or R. prowazekii . Human sera were obtained from individuals who had recovered from laboratory infections with either typhus rickettsia months or years previously. Goat-derived anti-immunoglobulins were conjugated to alkaline phosphatase with glutaraldehyde. Although the PR and YS antigens gave equivalent antibody titers in the complement fixation test, the PR antigen was clearly superior in the ELISA. With this antigen, the titration curves of all antisera were linear over a wider range of serum concentrations and the titers were higher than with the YS antigen. With YS and PR antigens, ELISA titers were higher than those obtained by complement fixation by one and two orders of magnitude, respectively. In human sera, immunoglobulin G and immunoglobulin M antibodies were demonstrated by their respective anti-immunoglobulins and by differential susceptibility to ethanethiol. ELISA titers showed some type specificity, whereas none was observed in complement fixation tests. The ELISA is highly sensitive, reproducible, and easily adaptable to the various requirements of clinical and research laboratories.

scholarly journals Analysis of antibody assay methods and classes of viral antibodies in serodiagnosis of cytomegalovirus infection

1978 ◽  
Vol 8 (2) ◽  
pp. 153-159 ◽  
Author(s):  
N E Cremer ◽  
M Hoffman ◽  
E H Lennette
Keyword(s):  
Antibody Titer ◽  
Complement Fixation ◽  
Gradient Centrifugation ◽  
Immunoglobulin M ◽  
Serum Specimen ◽  
Antibody Assay ◽  
Indirect Hemagglutination ◽  
Antibody Titers ◽  
Apparent Reason ◽  
Assay Methods

Forty-nine serum pairs with antibody to cytomegalovirus (CMV) were evaluated for rises in antibody titer (greater than or equal to fourfold) by indirect hemagglutination (IHA) and complement fixation (CF), using a freeze-thaw antigen (FT) and a glycine extract antigen (GE). In this sample CF-FT detected more rises in antibody titer than did CF-GE. IHA detected the least number. The apparent reason for stationary antibody titers with CF-GE and IHA was the presence of high antibody titers in the first serum specimen. Separation of immunoglobulin classes of 20 serum pairs by sucrose gradient centrifugation indicated that these antibodies with IHA were of the immunoglobulin M (IgM) class and those with CF-GE were of the IgG class. By separation of immunoglobulin classes, rises in IgG CMV antibody titers were seen with IHA, rises not observed in the whole serum because of high IgM antibody titers in the first serum specimen. Absence of rises in antibody titers with CF-FT was due in part to too early sampling of the second serum specimen (less than 21 days) and in part to an apparent inability of some individuals to respond with antibody reactive with FT antigen. CF-GE and CF-FT antibodies of the IgM class were detected in some sera, usually in specimens collected more than 10 days after the onset of symptoms. Although reactive with CMV antigen, the specificity of these IgM antibodies in relation to rheumatoid factor requires clarification.

Complement fixation by pig immunoglobulin M and its enzymic fragments

FEBS Letters ◽  
1976 ◽  
Vol 62 (1) ◽  
pp. 105-107 ◽  
Author(s):  
D. Beale ◽  
D.G. Dunham ◽  
C.M. Kent
Keyword(s):  
Complement Fixation ◽  
Immunoglobulin M
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