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D B Bloch

Publications and source records attributed to D B Bloch.

25 records · Page 2Linked to original sources
PubMed1989

Allelic exclusion and lymphocyte development. Lessons from transgenic mice.

The generation of an appropriate, specific immune response to an antigen is a remarkable biological phenomenon. An examination of both allelic exclusion and lymphocyte development is critical for an understanding of this response. Over the last several years, studies using transgenic mice that carry immunoglobulin or T cell receptor transgenes have provided a more detailed understanding of the mechanism of allelic exclusion. Recently, these mice have been used to examine lymphocyte development. In the future, these mice may be used to study the role of lymphocytes in autoimmune diseases.

Alleles↗
PubMed1988

Identification of cDNA encoding an additional alpha subunit of a human GTP-binding protein: expression of three alpha i subtypes in human tissues and cell lines.

The guanine nucleotide-binding proteins (G proteins), which mediate hormonal regulation of many membrane functions, are composed of alpha, beta, and gamma subunits. We have cloned and characterized cDNA from a human T-cell library encoding a form of alpha i that is different from the human alpha i subtypes previously reported [Didsbury, J. R., Ho, Y.-S. & Snyderman, R. (1987) FEBS Lett. 211, 160-164 and Bray, P., Carter, A., Guo, V., Puckett, C., Kamholz, J., Spiegel, A. & Nirenberg, M. (1987) Proc. Natl. Acad. Sci. USA 84, 5115-5119]. alpha i is the alpha subunit of a class of G proteins that inhibits adenylate cyclase and regulates other enzymes and ion channels. This cDNA encodes a polypeptide of 354 amino acids and is assigned to encode the alpha i-3 subtype of G proteins on the basis of its similarity to other alpha i-like cDNAs and the presence of a predicted site for ADP ribosylation by pertussis toxin. We have determined the expression of mRNA for this and two other subtypes of human alpha i (alpha i-1 and alpha i-2) in a variety of human fetal tissues and in human cell lines. All three alpha i subtypes were present in the tissues tested. However, analysis of individual cell types reveals specificity of alpha i-1 expression. mRNA for alpha i-1 is absent in T cells, B cells, and monocytes but is present in other cell lines. The finding of differential expression of alpha i-1 genes may permit characterization of distinct physiological roles for this alpha i subunit. mRNA for alpha i-2 and alpha i-3 was found in all the primary and transformed cell lines tested. Thus, some cells contain all three alpha i subtypes. This observation raises the question of how cells prevent cross talk among receptors that are coupled to effectors through such similar alpha proteins.

Amino Acid Sequence↗
PubMed1988

The gene for the alpha i1 subunit of human guanine nucleotide binding protein maps near the cystic fibrosis locus.

The gene for the alpha i1 subunit of human guanine nucleotide binding (G) protein was mapped by in situ hybridization to chromosome 7 at band q21. The regional chromosomal location of the human alpha i1 gene was confirmed using human/mouse somatic-cell hybrid lines containing portions of human chromosome 7. Because the alpha i1 gene mapped near the cystic fibrosis locus and because an abnormal G protein might be expected to contribute to the pathophysiology of this disease, the alpha i1 gene was mapped with respect to the cystic fibrosis locus as defined by the Met oncogene and anonymous DNA marker pJ3.11. The location of the alpha i1 gene proved to be distinct from that of the cystic fibrosis locus.

Chromosome Banding↗
PubMed1983

Cells on microspheres: a new technique for flow cytometric analysis of adherent cells.

Technical problems have previously prevented the application of fluorescence activated cell sorting to the study of adherent cell populations. We have developed a procedure for attachment of human monocyte-macrophages to 14-20 micrometer microspheres. These adherent cells on microspheres retained phagocytic capacity, could be stained for cell surface antigens using indirect immunofluorescence, and could be maintained in long-term culture. They could be examined and sorted on a fluorescence activated cell sorter while still in the adherent state. This technique facilitates the flow cytometric study of adherent cells and permits the isolation of subpopulations of these cells.

Animals↗
PubMed1979

Intestinal uptake of macromolecules. VI. Uptake of protein antigen in vivo in normal rats and in rats infected with Nippostrongylus brasiliensis or subjected to mild systemic anaphylaxis.

Adult Sprague-Dawley rats weighing approximately g were fed bovine serum albumin and sodium bicarbonate by gavage. Serum was obtained at intervals after feeding and tested for immunoreactive bovine serum albumin by radioimmunoassay. Nanogram amounts of immunoreactive bovine serum albumin were detected in serum; peak values were obtained after 4 and 6 hr. The influence of intestinal inflammation on protein uptake was examined in two model systems. Infection of rats with Nippostrongylus brasiliensis was accompanied by partial villous atrophy in the intestinal segments harboring adult worms and mild systemic anaphylaxis in the rat was accompanied by increased intestinal vascular and mucosal permeability. Enhanced uptake of BSA was observed before and shortly after self-cure of infection and during mild systemic anaphylaxis. The molecular size of immunoreactive bovine serum albumin approximated that of the administered bovine serum albumin; no small fragments of bovine serum albumin bearing antigenic determinants were detected.

Anaphylaxis↗