1986 |
Gregory, Richard L |
R03Activity Code Description: To provide research support specifically limited in time and amount for studies in categorical program areas. Small grants provide flexibility for initiating studies which are generally for preliminary short-term projects and are non-renewable. |
Antibody Responses to Igai and Igg Protease
The major objective of this grant is to determine the levels of antibodies in saliva and serum from caries-defined and periodontal disease-defined subjects to immunoglobulin A1 (IgA1) and IgG proteases isolated from culture supernatants of Streptococcus sanguis and Capnocytophaga ochracea, respectively. Naturally occurring antibodies to IgA1 protease in saliva and serum have recently been reported; however, it is not known if there are differences in the levels of these antibodies between various groups of individuals. IgA1 protease cleaves a particular proline/threonine linkage in the hinge region of the IgA1 subclass of IgA rendering it nonfunctional and it therefore is an important virulence factor which is produced by several different mucosal pathogens. IgG protease also cleaves the immunoglobulin which abrogates its' functional activity, however, much less is known about this enzyme than IgA1 protease. The purity and activity of the IgA1 and IgG protease antigens to be used to establish antibody levels will be determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and enzyme-linked immunosorbent assay (ELISA). Salivary and serum antibody levels will be determined using SDS-PAGE and ELISA and homogenous preparations of S. sanguis IgA1 and Capnocytophaga IgG proteases. Caries-resistant and -susceptible and periodontal disease-resistant and -susceptible individuals will be recruited using strict criteria. It is anticipated that caries-resistant and periodontal disease-resistant subjects will have higher levels of salivary and serum antibodies, respectively, to IgA1 and IgG proteases than caries-susceptible and periodontal disease-susceptible subjects. The higher levels of antibodies to IgA1 and IgG proteases in resistant individuals may prevent the enzymes from cleaving IgA1 and IgG, whereas the lower antibody levels in susceptible subjects may not neutralize the enzymes sufficiently to prevent them from cleaving IgA1 and IgG. The IgA1 and IgG proteases in the oral cavities of susceptible individuals may then cleave more potentially protective IgA and IgG antibodies and thus these subjects may be more at risk from disease than those having higher levels of enzyme-neutralizing antibodies. These proposed studies will significantly advance our understanding of the action of AgA1 and IgG proteases and their immunological properties.
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0.923 |
1988 — 1990 |
Gregory, Richard L |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Functional Role of Iga Antibodies to S Mutans
Oral immunization of humans and experimental animals with Streptococcus mutans antigens induces specific IgA enzyme- neutralizing antibodies which inhibit S. mutans growth, acid production and phosphotransferase (PTS), reduced numbers of plaque-adherent S. mutans and carious lesions suggesting that IgA antibodies inhibit some or all of the essential steps in S. mutans- induced cariogenicity such as adherence, glucan synthesis, production of lactate or other enzyme activities. The functional aspects of naturally occurring human salivary and colostral IgA1 and IgA2 and serum IgG, IgA and IgM antibodies and their interaction with the innate factors, lactoferrin, lysozyme and peroxidase in inhibiting virulence factors of S. mutans which are important in dental caries formation will be the major focus of this proposal. The levels, specificities and isotypes of parotid salivary and serum antibodies from caries-resistant (CR) and caries-susceptible (CS) subjects to S. mutans antigens will continue to be determined using an ELISA. IgA subclass antigenic specificity will be determined. IgA, IgG and IgM from immunized animals, CR and CS subjects and colostrum will be purified by affinity chromatography and used to treat S. mutans cells and purified enzymes to determine if the purified antibodies will inhibit S. mutans growth, adherence to glass surfaces, acid production, glucan synthesis and glucosyltransferase, fructosyltransferase, lactate dehydrogenase, PTS, dextranase and invertase activities. Kinetics of these enzyme activities will be examined. IgA will be subjected to jacalin chromatography and FPLC to isolate polymeric and monomeric IgA1 and IgA2 and will be used in our neutralization studies. Differences in avidity of CR and CS IgA1 and IgA2 antibody fractions will be studied. The differential effects of IgA1 and IgA2 from CR and CS subjects will be investigated by mixing the fractions and using them in the inhibition assays. Lactoferrin, lysozyme, peroxidase, fluoride and chlorhexidine will be added to the fractionated CR and CS IgA1 and IgA2 and used in our neutralization assays. The purified IgA1 and IgA2 from the CR and CS subjects and normal neutrophils will be examined for their ability to opsonize, phagocytize and kill S. mutans. The role of S. mutans fimbriae will be investigated as a potential vehicle for the adherence of the organism. These studies should provide valuable information on the actual function of IgA1 and IgA2 antibodies important in caries protection and the nature of the S. mutans antigen(s) most relevant in inducing protective immunity.
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0.923 |
1991 |
Gregory, Richard L |
S07Activity Code Description: To strengthen, balance, and stabilize Public Health Service supported biomedical and behavioral research programs at qualifying institutions through flexible funds, awarded on a formula basis, that permit grantee institutions to respond quickly and effectively to emerging needs and opportunities, to enhance creativity and innovation, to support pilot studies, and to improve research resources, both physical and human. |
Biomedical Research Support
health science research support; dentistry education;
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0.923 |
1998 — 2000 |
Hwu, Shiou-Jyh (co-PI) [⬀] Beyerlein, Adolph [⬀] Kolis, Joseph (co-PI) [⬀] Tritt, Terry (co-PI) [⬀] Gregory, Richard |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Acquisition of a Squid Magnetometer
This award from the Chemistry Research Instrumentation and Facilities (CRIF) Program will assist the Department of Chemistry at Clemson University acquire a superconducting quantum interference device (SQUID) magnetometer. This equipment will enhance research in areas which will include inorganic chemistry, magnetochemistry, solid state materials, magnetic nanoclusters, conducting polymers, superconductivity, thermoelectrics, and colossal magnetoresistance. The superconducting quantum interference device (SQUID) magnetometer measures very small currents or voltages and permits precise magnetic measurements of materials.
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0.957 |
2000 — 2001 |
Ogale, Amod (co-PI) [⬀] Gregory, Richard Smith, Dennis (co-PI) [⬀] Harrison, Graham [⬀] |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Acquisition of An Extensional Rheometer For Materials Research and Education
0076257 Harrison
This IMR grant supports the acquisition of an extensional rheometer in the Chemical Engineering department at Clemson University. The instrument will support the research of two young and two midcareer scientists in the investigation of extensional viscosity in polymers and polymer blends. The study facilitated by this instrument will allow a more complete characterization of a broad class of materials and lead to the development of new materials engineered with particular extensional properties. The rheometer will also enable current and future students to study extensional properties and investigate the influence of these properties on materials processing. Examples of materials to be studied are highly entangled polymer solutions and melts, polymer blends, composite materials and suspensions.
Plastics and rubbers have extraordinary properites when they are squeezed or stretched. Pulling them apart involves measures such as extensional viscosity which play a vital role in the mechanical properties of these materials. The instrument acquisition supported by this grant is to help study the mechanical propertis of these technologically critical materials.
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0.957 |