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R G Cook

Publications and source records attributed to R G Cook.

At least 145 records · Page 8Linked to original sources
PubMed1983

Expression of the thymus leukemia antigen by activated peripheral T lymphocytes.

Peripheral T lymphocytes activated in vitro with concanavalin A (Con A) or alloantigens express the thymus leukemia (TL) alloantigen as assessed by staining with the monoclonal antibody TL.m3 and flow cytometric analysis. The determinants detected by TL.m3 on activated cells are encoded within the Tla region and are detected as early as 48 h after activation with Con A. Several long-term cloned cytotoxic T lymphocyte lines were also examined and each expressed TL. By two-dimensional analysis, the TL isolated from activated peripheral cells was indistinguishable from that found on thymocytes and the leukemia cell line ASL-1.

Animals↗
PubMed1983

The Qa-1 alloantigens. II. Evidence for the expression of two Qa-1 molecules by the Qa-1d genotype and for cross-reactivity between Qa-1 and H-2K.

The nature of cell surface determinants detected by Qa-1-specific alloantisera and cytotoxic T lymphocytes (CTL) in mice of the H-2f, Qa-1d genotype was investigated. The H-2f, Qa-1d strains A.CA and B10.M express both Qa-1a and Qa-1b encoded alloantigenic determinants (Qa-1.1 and Qa-1.2, respectively), as defined in the prototypic A (or B6-Tlaa) and C57BL/6 (or A-Tlab) strains, respectively. Both anti-Qa-1.1 and -Qa-1.2 sera immunoprecipitate 46K m.w. glycoproteins from H-2f, Qa-1d strains. In addition to 46K m.w. proteins, anti-Qa-1.1 sera, but not anti-Qa-1.2 sera, precipitate 55 to 75K m.w. proteins; the nature of these proteins and their relationship to Qa-1 is unclear at present. Sequential immunoprecipitation experiments and the analysis of several recombinant strains revealed that anti-Qa-1.1 sera also cross-react with a 46K m.w. H-2f-encoded alloantigen, probably H-2Kf. Both Qa-1.1 and the non-Qa-1.1 cross-reacting determinants were detected by polyclonal anti-Qa-1a CTL on the Qa-1d strains. The Qa-1a encoded but not the cross-reacting determinants were detected by a cloned anti-Qa-1a CTL line. Sequential immunoprecipitation experiments on the recombinant strains B6.AC2 and B10.M(17R), which are Qa-1d but not H-2Kf, revealed that the Qa-1.1 and Qa-1.2 determinants do not reside on the same molecule. Furthermore, although Qa-1b-encoded determinants were detected on these strains with anti-sera and with bulk CTL cultures, cloned anti-Qa-1b CTL lines thus far analyzed have failed to react with Qa-1d targets, indicating that some but not all of the prototypic Qa-1b-encoded determinants are expressed by the Qa-1d strains.

Animals↗
PubMed1982

Qa-1-associated antigens. IV. Evidence for additional Qa-1 polymorphism defined biochemically and by cytotoxic T lymphocyte recognition.

Qa-1-specific, H-2-unrestricted cytotoxic T lymphocytes (CTLs) generated from reciprocally immunized B10.BR (H-2k, Qa-1a) and CBA (H-2k, Qa-1b) mice, and immunoprecipitation of cell surface Qa-1 were used to examined Qa-1 region determinant expression by H-2r and H-2f mice. The H-2b, Qa/Tla congenic mice B6-Tlaa and C57BL/6J (B6) were used as prototype Qa-1a and Qa-1b strains, respectively. Cells from H-2r strains expressed determinants recognized by B10.BR anti-CBA CTLs. Reciprocal cold target inhibition of cytolysis demonstrated that some, but not all, Qa-1b-associated determinants recognized on B6 were expressed by H-2r, Qa-1c cells. In contrast, cells from H-2f strains expressed Qa-1 determinants recognized by both B10.lBR anti-CBA and by CBA anti-B10.BR CTLs. Cold target inhibitions indicated that the H-2f, Qa-1d cells expressed some, but not all, Qa-1a-associated antigens recognized on B6-Tla and did not express the same Qa-1b-associated antigens as B6. Furthermore, H-2f strains expressed cell surface antigens immunoprecipitable by antisera specific for both Qa-1a and Qa-1b-encoded determinants; these molecules were of the same molecular weight as those immunoprecipitated from B6 and B6-Tlaa. These data suggest that CTLs and antisera define the same, closely related Qa-1 determinants encoded by a polymorphic locus.

Animals↗
PubMed1981

The Qa-1 alloantigens. I. Identification and molecular weight characterization of glycoproteins controlled by the Qa-1a and Qa-1b alleles.

Splenocytes from the Qa-Tla congenic strain pairs, A and A-Tlab or B6 and B6-Tlaa, were biosynthetically labeled with 3H-amino acids or cell surface labeled with 125I. Membrane proteins were solubilized with detergent and chromatographed on lentil lectin-Sepharose, and the resulting adherent pools were immunoprecipitated with antisera specific for determinants controlled by the Qa-1a and Qa-1b alleles, Qa-1.1 and Qa-1.2, respectively. Polyacrylamide gel electrophoresis analysis of immunoprecipitates from biosynthetically labeled preparations indicated that both the Qa-1.1 and Qa-1.2 antigens were glycoproteins with a m.w. of approximately 46,000. Qa-1.2 isolated from radioiodinated spleen cells similarly had a m.w. of 46,000. Analysis of anti-Qa-1.1 precipitates from 125I-labeled Qa-1a lysates demonstrated in addition to the 46,000 m.w. component, an electrophoretically heterogeneous protein or series of proteins in the m.w. range of 55,000 to 75,000. The specificity of these reactivities was shown by both antiserum and genetic control immunoprecipitations. These findings indicate that the Qa-1.1 and Qa-1.2 antigens are cell surface glycoproteins that are distinct from the TL antigens, and suggest a further complexity at the Qa-1--Tla locus.

Alleles↗
PubMed1981

Biochemical characterization of Ia alloantigens in guinea pigs. II. Comparative peptide mapping of Ia antigens from B cells, T cells, and macrophages.

Radioactive Ia.4 molecules were prepared from 3H- or 14C-labeled splenocytes, selected PEL, or bronchoalveolar macrophages (M phi). Studies in the accompanying paper indicated that incorporation into Ia.4 in these 3 populations is due to B cells, T cells, and macrophages, respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to isolate the 58,000 m.w. form of Ia.4. The eluted molecule was then reduced, and the resultant alpha and beta subunits were isolated by a second separation on SDS-PAGE. Alpha (or beta) chains from 1 population labeled with 3H-amino acids was mixed with alpha (or beta) chains obtained from a population representing a different cell type that was labeled with 14C-amino acids and the mixture was digested with trypsin. Double-label (3H/14C) comparative peptide mapping was performed using high-pressure liquid chromatography to separate the peptides. Eighteen to 20 peaks of radioactivity were resolved from alpha chains, and 12 to 15 from beta chains. No reproducible differences were observed when comparing alpha or beta chains of T cells and macrophages, or those of B cells and macrophages. These results indicate that the primary structure of Ia.4 molecules is identical on the 3 cell types in question. The implications of having a T cell bearing the same Ia that it recognized on a macrophage in conjunction with antigen is discussed.

Amino Acids↗
PubMed1980

Structural studies on the murine Ia alloantigens. VII. Further evidence for two-gene control of the E/C alloantigens.

By utilizing comparative tryptic peptide analysis of the E/C alloantigens from additional H-2 recombinant strains, the gene encoding the E/C beta subunit was localized to the I-A or B subregions. By peptide mapping techniques, the E/C alpha- and beta-chains showed little structural homology with the A alloantigen alpha and beta subunits. In addition, comparisons of the E/C beta subunits from F1 strains (b x d) with those from both parental strains revealed that in a heterozygote the beta subunit from either allele (b or d) can associate with the alpha-chain from one allele (d). Thus, the formation of hybrid E/C antigens by cis-trans gene complementation increases the E/C alloantigen repertoire in heterozygotes.

Amino Acid Sequence↗
PubMed1979

Organization of the immune response genes.

The I region of the major histocompatibility complex contains immune response genes that display considerable polymorphism; that is, there are many alleles at each locus. These genes regulate the immune response to antigen by mediating intercellular communication among lymphoreticular cells. An analysis of the primary structure of the products of two subregions of (I-A, I-E/C) was undertaken in order to understand the genetic organization of the region, the evolution of the genes and, eventually, their function.

Alleles↗
PubMed1979

Structural studies on the murine Ia alloantigens. V. Evidence that the structural gene for the I-E/C beta polypeptide is encoded within the I-A subregion.

The E/C alpha- and beta-subunits of intra-I-region recombinants were analyzed for primary structural variation by comparative tryptic peptide mapping. The E/C alpha-polypeptides from B10.A, B10.A (3R) and B10.A (5R) showed complete coincident elution of peptides; the E/C beta-chains from B10.A and 3R (or 5R) were approximately 40% different. This suggests that the structural gene for the E/C beta-polypeptide is within the I-A subregion.

Amino Acid Sequence↗
PubMed1979

Surface expression and synthesis of I-A and I-E/C encoded molecules by B lymphocytes and Ig-secreting cells.

Splenocytes from recombinant mice were radiolabeled before or after deletion of subpopulations by cytotoxic anterisera (+C) directed against I-A, I-E/C, IgM, or Ig. Examination of the lysates of the surviving cells by immunoprecipitation demonstrated that 1) virtually all I-A and I-E/C molecules are co-expressed and synthesized by Ig+, IgM+ lymphocytes, 2) I-A, I-E/C, and IgM molecules are present on many of the cells secreting IgM and IgG, and 3) populations of Ig-bearing or Ig-secreting cells that lack detectable I-A and I-E/C antigens can be identified in spleen cell populations. The co-expression of I-A and I-E/C on most cells of the B cell lineage is discussed in terms of our present concepts of Ir gene control of immune responses.

Animals↗
PubMed1979

Structural studies on the murine Ia alloantigens. IV. NH2-terminal sequence analysis of allelic products of the I-A and I-E/C subregions.

Murine Ia alloantigens encoded by the I-A and I-E/C subregions were isolated from radiolabeled splenic lysates and examined by NH2-terminal sequence analysis. Haplotype-associated sequence variation was detected in the beta, but not alpha, subunits of both the A and E/C alloantigens. The A beta-polypeptides from k and b haplotypes show four differences in the 12 positions compared, whereas the E/C beta-polypeptides from k and r haplotypes show two differences in the 13 positions compared. No sequence variation was detected between the Ak and Ab alpha-chains (six positions compared) or between the E/Ck and E/Cr alpha-chains (11 positions compared). Homology relationships between these murine Ia alloantigens and the human Ia (DR) alloantigens are also presented.

Alleles↗
PubMed1979

Structural studies on the murine Ia alloantigens. VI. Evidence that both subunits of the I-A alloantigen are encoded by the I-A subregion.

The alpha and beta subunits of the murine I-A alloantigens from several H-2 haplotypes were examined by comparative tryptic peptide mapping by using double label (3H and 14C) techniques. Significant structural variation between alleles was detected in both subunits. Tryptic digests of the alpha polypeptides from s, b, and d showed only 65% co-elution with k; beta-chains from s, b, d, and r were about 50% similar to the k beta subunit. Peptide analysis of the Ak subunits from intra-H-2 recombinant strains indicated that both the alpha and beta polypeptides are encoded within the I-A subregion.

Animals↗
PubMed1978

Structural studies on protein products of murine chromosome 17. III. Partial amino acid sequence of an H-2Kq molecule.

Twenty-one of the amino terminal twenty-seven amino acid residues have been assigned in the murine H-2Kq molecule and several additional assignments and corrections have been made in both the H-2Kk and H-2Kb molecules. The study shows that 1) H-2Kk and H-Kq, which are serologically related, have an identical amino acid sequence for all twenty positions that can be compared, 2) the H-2Kk and H-2Kq molecules differ from H-2Kb at only two positions--9 and 22, and 3) the additional sequence data on the H-2Kk, -Kb, and -Kq molecules increases the already striking homology between murine and human transplantation antigens.

Amino Acid Sequence↗
PubMed1978

Structural studies on the murine IA alloantigens. II. Molecular weight characterization of the products of the I-A and I-E/C subregions.

Murine splenocytes were radiolabeled with 3H- and 14C-amino acids; the Ia alloantigens encoded by the I-A and I-E/C subregions were isolated by immunoprecipitation and analyzed for structural variation by polyacrylamide gel electrophoresis. The I-A subregion products (k, d, and b haplotypes) are composed of two polypeptides, alpha and beta, with m.w. of 34,000 and 26,000 daltons, respectively. Haplotype-associated differences in m.w. were detected in the I-E/C products of the k, r, p, and d haplotypes. The alpha and beta chains of E/Ck and E/Cr are 34,000 and 28,000 daltons, respectively; E/Cp and E/Cd molecules are composed of 31,000 and 29,000 dalton polypeptides. Thus, there is both subregion (I-A vs I-E/C) and haplotype (E/Ck, E/Cr vs E/Cd, E/Cp) associated variation in the m.w. of the Ia alloantigens. Additionally, the covalent vs noncovalent association of the Ia subunits was examined and it was found that the alpha and beta chains of both I-A and I-E/C are not covalently associated. However, the I-A alpha and beta chains tend to associate through disulfide bonds during detergent lysis; the presence of alkylating agents during cell lysis prevents this association, and only free alpha and beta chains are observed under nonreducing conditions.

Animals↗