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Biomedical subjects

D Pressman

Publications and source records attributed to D Pressman.

At least 73 records · Page 4Linked to original sources
PubMed1976

Location of light chain tyrosine peptides from the combining site of a rabbit anti-p-azobenzoate antibody.

Peptic peptides containing a tyrosyl residue from the binding site of a rabbit anti-p-azobenzoate antibody were isolated by means of the paired-iodination procedure. The peptides were from the light chain, and the tyrosyl residue is 29, 30, 31, 32, 32A, 32B, 33 at position 30 in the sequence -Val-Tyr-Asn-Asx-Lys-Gly-Leu- and thus is in the first hypervariable region. The sequence of the N-terminal 40 residues was determined. The major antibody-site peptide isolated was a diiodotyrosyl (DIT) tetrapeptide representing residues 30-32A; the monoiodotyrosyl (MIT) tetrapeptide was also isolated, but in a smaller yield. By isoelectric focusing, the light chain appeared to be homogeneous. No heterogeneity was apparent in the light chain sequencing until position 32B when, in addition to the phenylthiohydantoin derivative of tyrosine present as the major residue, a significant amount of the phenylthiohydantoin derivative of glycine was obtained. The glycine presumably represents a light chain variant population and explains the source of the other antibody-site peptides isolated, i.e. two pentapeptides, apparently of the sequence Tyr-Asn-Asx-Lys-Gly, isolated as the DIT and MIT derivatives. The tetrapeptides must have been derived from the peptic cleavage between Lys 32A and Tyr 32B in the major light chain variant and the pentapeptides from the peptic cleavage between Gly 32B and Leu 33 in the other variant. It is interesting that position 30 is occupied by a tyrosyl residue in five out of twelve other rabbit antibody light chains of known sequence (Margolies, M.N. et al., Proc. Nat. Acad. Sci. US 1975.72: 2180). One light chain is from another rabbit anti-p-azobenzoate antibody in which Tyr 30 is apparently not important in hapten binding although a tyrosyl at position 96 is clearly involved in hapten binding (Roholt, O.A. et al., J. Immunol. 1973.111:1367). The other four of the five light chains are from anti-pneumococcal polysaccharide antibodies in which the role of this tyrosyl residue is not known.

Amino Acid Sequence↗
PubMed1976

Absence of a serologically detectable association of murine beta2-microglobulin with the embryonic F9 antigen.

The association of murine beta2-microglobulin to the early embryonic F9 antigen has been investigated by indirect immunofluorescence and by radioimmunoassay. Although some cell lines carry both types of molecules, the beta2-microglobulin was not found expressed on primitive teratocarcinoma cells, where F9 antigen was primarily detected. It is concluded that the low m.w. (12,000 daltons) subunit that was reported to be associated to the F9 antigen is not the adult beta2-microglobulin.

Animals↗
PubMed1976

The component fragments obtained by acid dissociation of papain-solubilized H-2 molecules.

H-2Kk and H-2Dd molecules were specificially purified from a radioiodinated H-2a preparation obtained by papain digestion of spleen cell membranes of A/J strain mice. The molecules were isolated by binding to H-2 alloantisera of the corresponding private specificity followed by precipitation with rabbit anti-mouse IgG antiserum. The specifically precipitated radioiodinated H-2Kk and H-2Dd molecules were dissociated by acid treatment into large and small components of about 37,000 and 11,000 respectively. These were separated by gel filtration at acid pH or by gel isoelectric focusing in the presence of 6 M urea. Each component separated by gel filtration of the acid-dissociated H-2 molecules showed a high degree of size homogeneity as determined by sodium dodecyl sulphate-acrylamide gel electrophoresis. Upon gel isoelectric focusing, however, the small components showed two peaks of radioactivity closely located together at pH 7-8, both of which had a restricted pH range, while the large components gave one peak of a relatively wide pH range of pH 5-6. The H-2Kk and H-2Dd molecules gave essentially the same pattern in terms of the numbers and the positions of the radioactivity bands. Under the iodination conditions used the large components of H-2Kk molecules contained more radioactivity than the small components, while the reverse was true in case of H-2Dd molecules. Such a difference was also found with H-2Kk and H-2Dd molecules isolated by use of alloantisera of the respective public specificity. The assay of binding of the isolated components with H-2 alloantisera of defined specificity revealed that the large components retain most of the allospecificities of the parental H-2 molecules. No H-2 allospecificities were found on the small components. The small components showed extensive binding with rabbit antiserum against mouse beta2-microglobulin. The same antiserum did not show any binding with the large components. On the other hand, both of the components did bind with rabbit antiserum against papain-solubilized H-2 molecules.

Animals↗
PubMed1976

Chromosomal assignment of the HL-A common antigenic determinants in man-mouse somatic cell hybrids.

In the study presented here, man-mouse somatic cell hybrid clones were examined by means of radioimmunoassays for the presence of both beta2-microglobulin (beta2m) and the HL-A xenoantigenic determinant. In addition, the clones were examined for their karyotype and the expression of enzymes with known chromosomal assignments. The results obtained indicate that the gene coding for the HL-A xenoantigenic determinant is carred on chromosome 6. The data obtained provides a direct demonstration that the gene coding for beta2m segregates independently of that coding for the alloantigenic polypeptide chain of the HL-A molecule, and that the gene coding for beta2m is carried on chromosome 15.

Animals↗
PubMed1976

A mouse plasma substance carrying beta2-microglobulin activity and lacking in H-2 alloantigenic activity.

A mouse plasma substance carrying beta-2-microglobulin activity and lacking in H-2 alloantigenic activity was separated from the blood plasma of A/J strain female mice. The plasma substance had a molecular size of about 300,000-400,000 daltons and an electrophoretic mobility of alpha-globulin. The plasma substance was split by papain digestion to a fragment of about 50,000-60,000 daltons that still carried beta2-microglobulin activity. The papain-split plasma substance was devoid of H-2 alloantigenic activities and Thy-1 and TL alloantigenic activities as well, but yet had a two-component structure that was similar to papain-solubilized H-2 molecules. It contained a 37,000-dalton component linked non-covalently to an 11,00-dalton component, i.e. mouse beta2-microglobulin. This plasma substance appears to be different from Ss protein or Slp protein, both found in mouse serum.

Animals↗
PubMed1976

Detection of liver-bound metabolites of azocarcinogens by the use of anti-hapten antibodies.

The presence of the azocompounds, p-dimethylaminoazobenzene and 3'-methyl-p-dimethylaminoazobenzene, and p-amino-N-acetyl-N-methylaniline (or their metabolites) bound to components of the liver cells of rats fed a single large dose of each compound has been detected using rabbit antibodies raised against the p-azo-N-acetyl-N-methylaniline hapten in the indirect fluorescent antibody technique. Binding of these antibodies was seen on liver sections from rats fed any one of these compounds. When the anti-p-azo-N-acetyl-N-methylaniline antiserum was absorbed with either liver sediments or cytosol fractions from rats fed p-amino-N-acetyl-N-methylaniline, the antibodies reacting with the liver-bound compounds were removed from the antiserum. Also, absorption of the antiserum with liver sediments or cytosol fractions of rats fed either one of the azocompounds selectively removed all of the antibodies reacting with the livers of rats fed that compound but did not remove other antibodies that were still capable of reacting with liver cells of rats fed the other azocompound or p-amino-N-acetyl-N-methylaniline. Thus this antiserum appears to contain several different anti-p-azo-N-acetyl-N-methylaniline antibodies with different structural requirements for reaction. Some can react with the azocompounds or certain of their metabolites, while others require more of the p-azo-N-acetyl-N-methylaniline structure for reaction. Some of the antibodies appear to react with liver-bound p-dimethylaminoazobenzene but not with liver-bound 3'-methyl-p-dimethylaminoazobenzene, while still others react with 3'-methyl-p-dimethylaminoazobenzene but not with p-dimethylaminoazobenzene.

Aniline Compounds↗
PubMed1976

Identification of heavy chain tyrosine 33 in the binding site of myeloma protein McPC 603 by paired label iodination.

The phosphorylcholine binding mouse myeloma protein McPC 603 has been shown to have tyrosyl residues in its binding sites by the fact that iodination of the protein causes extensive loss of binding activity which can be substantially retained when the protein is iodinated with sites occupied by ligand. Paired label iodination of McPC 603 protein allowed identification of the tyrosine involved and showed the tyrosine to be in the heavy chain. Gel filtration of heavy chain peptides enabled the tyrosyl-containing peptide of interest to be identified as the N-terminal 33 residue peptide in which the only tyrosine is Tyr 33. Thus H chain Tyr 33 was shown to be a contact amino acid residue in the site of McPC 603 protein. These results provide chemical evidence confirming previously reported x-ray crystallographic identification of H chain Tyr 33 in the site of McPC 603 protein.

Amino Acid Sequence↗
PubMed1976

Receptor-blocking factor present in immune serum resembling auto-anti-idiotype antibody.

Previous studies have shown that rabbit antibody-forming cells in the primary and secondary response possess cell-associated antigen-binding receptors. In the present study, we demonstrate that a factor appears in the serum of rabbits following immunization which inhibits the antigen binding of up to 60% of the receptor-bearing antibody-forming cells in both the primary and secondary response. These observations were made on lymph node cells from rabbits primed with either sheep red blood cells (SRBC)3 or 3-nitro-4-hydroxy-5-iodophenylacetic acid coupled to keyhole limpet hemocyanin (NIP-KLH). The inhibitory activity is not associated with anti-SRBC or anti-NIP antibody. In the primary response to SRBC, the antigen binding by day 6 antibody-forming cells is inhibited by the autologous days 7 to 10 inactivated and absorbed serum. In the secondary response to SRBC, the inhibitory factor peaks in the serum around day 10. Later, in both the primary and secondary immune response to SRBC, the inhibitory activity of the serum decreases rapidly. In the primary response to NIP-KLH, the inhibitory activity of the immune sera increased from day 7 through day 14. The receptor-inhibiting factor is antigen specific since the serum from SRBC-primed rabbits inhibits SRBC binding by anti-SRBC antibody-forming cells, but it does not inhibit NIP binding by anti-NIP antibody-forming cells. Similarly, serum from NIP-KLH-primed rabbits inhibits NIP binding by anti-NIP antibody-forming cells, but does not inhibit the SRBC receptor on the anti-SRBC antibody-forming cells. The inhibition is not due to the presence of antihapten or anti-SRBC antibody competing with receptor sites, since the immune sera from one SRBC-primed animal inhibit antigen binding of its own antibody-forming cells, but do not inhibit the antigen binding of antibody-forming cells from other SRBC-primed rabbits.

Animals↗