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C R Parish

Publications and source records attributed to C R Parish.

At least 181 records · Page 10Linked to original sources
PubMed1974

Lack of a correlation between cell-mediated immunity to the carrier and the carrier-hapten helper effect.

The relationship between cell-mediated immunity to the carrier and the carrier-hapten helper effect was studied in the rat by using three forms of the carrier which differed in their capacity to induce carrier-specific delayed-type hypersensitivity. The three carriers were polymerized flagellin (POL), flagellin (FIN), and acetoacetylated flagellin (AFIN), which induced FIN-specific delayed-type hypersensitivity in the order AFIN > FIN > POL. Helper cells for the anti-DNP antibody responses to a range of DNP-FIN conjugates appeared to be almost inversely related to cell-mediated immunity to the carrier, being in the order POL > FIN =/> AFIN. These differences occurred whether the carriers were injected in saline or FCA, but were less pronounced with the heavily DNP-conjugated flagellins.

Animals↗
PubMed1972

Immune response to chemically modified flagellin. 3. Enhanced cell-mediated immunity during high and low zone antibody tolerance to flagellin.

High and low zone antibody tolerance to bacterial flagellin can be induced in adult strain W Wistar rats by multiple injections of a cyanogen bromide (CNBr) digest of flagellin at two widely spaced dose levels. Intermediate doses of the CNBr digest produce enhanced antibody titers to flagellin rather than antibody tolerance. Studies reported in this paper revealed that both high and low zone antibody tolerance to flagellin were accompanied by heightened levels of delayed-type hypersensitivity. Conversely, when enhancement of the antibody response occurred, suppression of delayed hypersensitivity was observed. This inverse relationship between humoral and cell-mediated immunity was very striking in strain W Wistar rats but was not quite so clear-cut in another strain of Wistar rats (strain J). Strain J rats were resistant to the induction of antibody tolerance and gave higher immunological responses to flagellin than strain W animals. In addition, it was observed that, in contrast to adult tolerance, administration of the CNBr digest to neonatal rats induced complete tolerance at the level of both humoral and cell-mediated immunity. These findings were discussed in the light of earlier studies with flagellin and provide further evidence for a previously described hypothesis.

Animals↗
PubMed1971

Immune response to chemically modified flagellin. I. Induction of antibody tolerance to flagellin by acetoacetylated derivatives of the protein.

Flagellin (mol. wt. 40,000) from S. adelaide organisms was acetoacetylated to varying extents with diketene (acetoacetic anhydride). Chemical studies demonstrated that the amino groups of flagellin were more readily acetoacetylated than the hydroxyl groups. Several antigenic tests revealed that as flagellin was acetoacetylated to increasing extents there was a steady decline in the affinity of the molecule for anti-flagellin antibodies. Loss in antigenic activity following acetoacetylation was not related to the number of acetoacetyl groups attached but was determined by the type of residue substituted. Reactive lysine residues were much less important anti-genically than easily substituted hydroxyl groups. Acetoacetylation very readily destroyed the antibody-forming capacity of flagellin in rats. This fall in immunogenicity was related to the antigenic activity of the preparations. In fact, only a 40% reduction in the antigenic activity of flagellin produced a 90-95% reduction in primary antibody formation. The more heavily acetoacetylated flagellins produced no detectable antibody and, in fact, rendered adult rats tolerant (in terms of antibody formation) to a subsequent challenge of flagellin. Tolerance was induced by acetoacetylated flagellins which had drastically reduced affinities for anti-flagellin antibodies. These results were interpreted as indicating that the affinity of antigen for receptors on cells appears to be of crucial importance in determining whether antibody formation or immunological tolerance (antibody suppression) occurs.

Acetoacetates↗
PubMed1971

Immune response to chemically modified flagellin. II. Evidence for a fundamental relationship between humoral and cell-mediated immunity.

Flagellin (mol.wt. 40,000) from S. adelaide organisms and a series of acetoacetyl derivatives of flagellin were tested for their ability to induce humoral and cell-mediated immunity in adult rats. It was found that unmodified flagellin was an excellent inducer of antibody formation but a poor inducer of delayed-type hypersensitivity. In contrast, increasing acetoacetylation steadily destroyed the ability of flagellin to initiate antibody formation but enhanced the capacity of the molecule to induce flagellin-specific cell-mediated immunity and antibody tolerance. In fact, it appeared that in adult rats antibody formation and cell-mediated immunity may well be opposing immunological processes. Furthermore, the affinity of the acetoacetyl flagellins for anti-flagellin antibodies appeared to determine the type of immune response which predominated. High affinity antigen produced antibody formation whereas low affinity antigen induced cell-mediated immunity and antibody tolerance. The importance of affinity was further evidenced by the fact that a CNBr digest of flagellin induced humoral and cellular immune responses identical to an acetoacetylated flagellin of comparable antigenic activity. From these studies it was proposed that both humoral and cell-mediated immunity can be directed against the same antigenic determinants but that the specificity requirements for delayed hypersensitivity (and antibody tolerance) are less than those required for antibody formation. Some remarkable immunological features of the flagellin system were revealed. Flagellin induced comparable delayed-type hypersensitivity when injected in either saline or FCA. Furthermore, FCA only slightly enhanced the delayed responses induced by the acetoacetyl flagellins and in fact these preparations produced antibody tolerance whether injected in saline or adjuvant. Finally, in contrast to the adult tolerance induced by the acetoacetylated flagellins, which existed only at the antibody level, tolerance in neonatal rats existed at the level of both humoral and cell-mediated immunity. This finding is the first indication of a fundamental difference between neonatal and adult tolerance. The significance of these findings is discussed in the light of current immunological concepts and a hypothesis proposed to explain these phenomena.

Acetoacetates↗
PubMed1969

Cleavage of bacterial flagellin with cyanogen bromide. Chemical and physical properties of the protein fragments.

1. Flagellin, isolated from the flagella of Salmonella adelaide, was shown by various criteria to be a pure protein. It had a molecular weight of about 40000 and contained three methionine, six tyrosine, 11 arginine and 25 lysine residues/mol., of which 11 of the lysine residues were present as in-N-methyl-lysine. 2. After treatment of flagellin with cyanogen bromide in formic acid, four main fragments (A, B, C and D) were obtained, with as many as six minor components that represented partial degradation products. The major fragments were estimated by amino acid analysis to have molecular weights of about 18000 for fragment A, 12000 for fragment B, 5500 for fragment C and 4500 for fragment D. Fragments A, B and D, but not fragment C, were recovered pure by gel chromatography as monitored by polyacrylamide-gel electrophoresis. 3. A complex between fragments C and D was also isolated (mol.wt. 10000) after limited oxidation of flagellin by chloramine-t before digestion by cyanogen bromide. After oxidation essentially only two fragments were released from flagellin by cyanogen bromide: the ;C,D' complex and a presumed ;AB' fragment. 4. The sum of the amino acid analyses of fragments A and B and the ;C,D' complex gave residue values that agreed well with the amino acid composition of native flagellin. 5. Fragments A and D contained tyrosine, and ten of the 11 in-N-methyl-lysine residues of the molecule were in fragment A. Reaction with [(125)I]iodide at small extents of substitution showed that, in flagellin, the tyrosine residue of fragment D was more readily substituted than those of fragment A. By contrast, in polymerized flagellin, the tyrosine residues of fragment A were more readily substituted. 6. Treatment of flagellin with carboxypeptidases A and B revealed the C-terminal sequence -Leu-Leu-Leu-Arg. Arginine and leucine were released by carboxypeptidase from the ;C,D' complex but not from fragment D, indicating that fragment C was C-terminal. 7. On the basis of the results from amino acid analysis, carboxypeptidase digestion, N-terminal analysis, iodination studies and polyacrylamide-gel electrophoresis, the sequence of fragments in flagellin was considered to be B-A-D-C; in the polymer, fragment A was exposed. It is suggested that methylation of the lysine residues occurred in the organism after flagellin had polymerized.

Amino Acids↗
PubMed1969

Cleavage of bacterial flagellin with cyanogen bromide. Antigenic properties of the protein fragments.

1. Four polypeptide fragments, obtained by cyanogen bromide treatment of the protein flagellin from Salmonella adelaide, were tested for their antigenic activity by using them as inhibitors in three different assays: bacterial immobilization, haemagglutination of sensitized erythrocytes and quantitative micro precipitation. Immunodiffusion studies were also performed on the protein fragments. 2. Cleavage of the flagellin molecule in this way gave no detectable loss of antigenic determinants. Fragment A (mol.wt. 18000), the largest of the polypeptides, contained all the antigenic specificities present on flagellin that were recognized by the antisera used. In one test, fragment B (mol.wt. 12000) also contained antigenic activity to an extent not easily explainable by contamination with fragment A. Fragments C (mol.wt. 5500) and D (mol.wt. 4500) appeared to be antigenically inactive.

Antigens↗