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Biomedical subjects

E Appella

Publications and source records attributed to E Appella.

At least 343 records · Page 19Linked to original sources
PubMed1977

Solubilized TSTA and the major viral structural proteins, gp70 and p30, in the immune response to murine leukemias induced by Friend and Rauscher virus.

Antigens present in gp70 and p30 purified from Rauscher virus, were tested for immunogenicity in various assays measuring the anti-tumor immune response against lymphocytic leukemias of Friend (FBL-3) or Rauscher (RBL-5) virus origin. p30 had no effect on in vitro cytotoxicity against tumor cell targets mediated by either an anti RBL-5 serum or lymphocytes from animals immunized with FBL-3 cells. gp70 had had no effect on serum-mediated cytotoxicity but used at high concentrations it inhibited cell-mediated cytotoxicity. When used to immunize mice directly against subsequent challenge with the RBL-5 and FBL-3 leukemias, p30 had no discernible effect, while gp70 afforded partial protection against RBL-5 but only at high concentrations. Cell-free preparations of tumor membranes containing negligible amounts of gp70 were antigenically superior to gp70 in both the in vitro and in vivo assays. It is concluded that antigens on these purified proteins that are also expressed on tumor cells are not major targets of the anti-tumor immune response in this system.

Animals↗
PubMed1977

Amino acid sequence of the first 217 residues of a mouse heavy chain (MOPC 47A) with a domain deletion.

Cyanogen bromide cleavage of the deleted heavy (alpha) chain of mouse IgA 47A yielded five peptides, CNBr 1-5, consisting of 34, 50, 28, 70, and 160 residues. A 217-residue NH2-terminal sequence, which comprises the variable region and the first domain of the constant region (CH1), and a 19-residue COOH-terminal sequence of the chain were obtained from the sequences of CNBr 1-4 and the NH2-terminal and COOH-terminal sequences of CNBr 5. The tryptic peptides of the remainder of the chain have been partially characterized. Comparison of these data with the sequences of other, nondeleted, chains reveals that the 47A chain terminates exactly at the end of the CH2 domain and that there are no deletions up to that point. It is concluded that the deletion in the chain is a single, large deletion consisting of the entire CH3 domain. The 47A chain also differs from other, nondeleted, mouse alpha chains derived from BALB/c strains in that it contains a labile cysteine at position 135, which is believed to participate in the light-heavy chain bond, and contains galactosamine in the hinge region. This may mean that the 47A alpha chain, in addition to being deleted, represents a mouse IgA subclass analogous to human IgA1.

Amino Acid Sequence↗
PubMed1977

Quantitative in vivo studies of soluble simian virus 40 tumor-specific transplantation antigens of the mouse.

Quantitative studies have been performed on the immunogenicity of a membrane-bound antigen of a simian virus 40 (SV40) -induced sarcoma in syngeneic BALB/c mice and of subcellular fractions derived from this tumor. The objectives of the investigation were: a) to develop a quantitative in vivo assay of the tumor-specific transplantation antigen (TSTA) and b) to compare the distribution of histocompatibility antigens, H-2, with that of the SV40 TSTA during several fractionation steps. The immunogenicity of the TSTA-containing fractions was assessed from dose-response curves relating tumor size and the amount of protein used for immunization. After digestion of the tumor cell membranes with a limited amount of papain, H-2 as well as TSTA were present in a soluble form. A single immunization with only 2 microng of the solubilized TSTA reduced the tumor size by 70% compared to that in nonimmunized control animals. The results of several fractionation steps suggest that H-2 and the TSTA are not tightly associated in the solubilized immunogenic material.

Animals↗
PubMed1977

Subcellular distribution of the tumor-specific transplantation antigen of simian virus 40-transformed cells.

TU-5, a simian virus 40 (SV40)-transformed cell line of BALB/c origin, expressed the SV40-specific T-antigen and a transplantation antigen (TSTA). Nuclei and plasma membranes were prepared from these cells and shown on the basis of the distribution of T-antigen and histocompatibility (H-2) antigens to be relatively free of cross contamination. Most of the TSTA, estimated by tumor rejection, was associated with the nuclear fraction.

Animals↗
PubMed1977

Biologic and biochemical properties of detergent-solubilized tumor-specific transplantation antigen from a simian virus 40-induced neoplasm: brief communication.

The detergent Nonidet P40 was used to solubilize tumor-specific transplantation antigens (TSTA) from crude membranes obtained from dissociated cells of simian virus 40-induced sarcoma of BALB/c mice. A good recovery of specific tumor rejection activity was observed. One fraction, fraction V, was obtained following polyacrylamide-agarose filtration of the solubilized material, and this fraction contained most of the activity. An increased specific activity followed gel filtration. Preliminary data from lectin column chromatography of the active fraction V indicated a separation of TSTA activity from H-2 activity.

Animals↗
PubMed1977

Biological and biochemical properties of Nonidet P40-solubilized and partially purified tumor-specific antigens of the transplantation type from plasma membranes of a methylcholanthrene-induced sarcoma.

Tumor-specific transplantation antigen (TSTA) was solubilized from cell membranes of sarcoma Meth-A with non-ionic detergent Nonidet P40. Soluble TSTA was partially characterized by chromatographic separation and electrophoresis. The antigen responsible for tumor rejection activity had a molecular weight of approximately 70,000 daltons in the presence of detergent and an electrophoretic mobility of alpha-globulin. TSTA was well separated from mouse histocompatibility antigen H-2 by a sequence of procedures, including gel filtration, lectin affinity chromatography, column electrophoresis, and rechromatography on agarose, showed only three major bands on polyacrylamide gel electrophoresis. TSTA was specific for sarcoma Meth-A.

Animals↗
PubMed1976

Studies on the structural localization of rabbit H chain allotypic determinants controlled by the a locus. Purification and immunological properties of an immunopeptide bearing a3 allotypic determinants.

An immunopeptide bearing a3 allotypic determinant(s) was isolated from the gamma chain of an a3 homozygous rabbit (G222-2) immunized with type III pneumococcal vaccine. Immunocogical properties of peptides were studied using a radioimmunoassay that involved inhibition by these peptides of a reaction between 125I-labeled anti-a3 antibody and Sepharose-bound a3 immunoglobulin G (IgG). The gamma chain was isolated from IgG of restricted heterogeneity and then citraconylated and digested with trypsin. The tryptic digest (TD1) was passed through an anti-a3 immunoabsorbent column either directly or after an intermediate step of Sephadex G-75 chromatography. The bound peptides (T1) were eluted with 0.1 M acetic acid and further digested with trypsin. The digest (TD2) was again run on the anti-a3 immunoabsorbent column to purify the bound immunopeptide T2. In the radioimmunossay this immunopeptide was found to have major a3 determinant(s). Its molecular weight was found to be approximately 6,000, which decreased to about 3,000 after reduction and alkylation. These data, together with NH2- and COOH-terminal analyses and cysteine peptide mapping, demonstrated that T2 is composed of two polypeptide chains linked by a disulfide bond, one from the cysteine 22 region having lysine at the COOH terminus and the other from the cysteine 92 region arginine at the COOH terminus. The lysine peptide was separated from the arginine peptide and its NH2-terminal sequence was found to be Gly-Asx-Glx-Ser-Thr-Cys. Since the cysteine is at position 22, the lysine peptide starts at position 17. It has approximately 22 residues. The framework sequence from 17 to 20 is different from those reported so far. In addition, the heavy chain used in these studies has some other unusual features including a histidine, probably in the first hypervariable region. The presence of histidine in the first hypervariable region of rabbit heavy chain has not been reported previously. The other peptide which is about 30 amino acids in length and ends with arginine 94, probably includes positions 67, 70, 71, 84, and 85 that are believed to have substitutions correlating with a allotypes. In a hypothetical three-deminsional model of the Fv portion of rabbit anti-SIII antibody BS-5, residues 17 to 33 of the lysine peptide and 67 to 79 and 84 to 85 which may be present in the arginine peptide are fully exposed on the surface and are far removed from the antibody combining site.

Amino Acids↗
PubMed1976

Comparative chemical analyses of the alloantigenic fragments of HL-A antigens.

Papain-solubilized HL-A antigens have been shown to contain two polypeptide fragments: beta2-micro-globulin with a molecular weight of approximately 12,000 and a larger fragment with a molecular weight of about 34,000. The large fragments isolated from two HL-A preparations carrying different specificities appeared homogeneous both by immunoelectrophoresis and sodium dodecyl sulfate-acrylamide electrophoresis. Both HL-A antigen preparations contained the same NH2-terminal (glycine) and the same COOH-terminal residue (serine). The carbohydrate content of the large fragment was 12.9%, making the carbohydrate-free molecular weight approximately 30,000. Small but significant differences have been found in the amino acid compositions and tryptic peptide maps of the two large fragments containing different specificities.

Amino Acids↗
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↗