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Biomedical subjects

P Barstad

Publications and source records attributed to P Barstad.

6 recordsLinked to original sources
PubMed1989

Monokine regulation of human immunodeficiency virus-1 expression in a chronically infected human T cell clone.

A T cell clone (ACH-2) derived from T cells infected with HIV-1 was found to produce HIV-1 in response to stimulation with a monokine-enriched supernatant prepared by culturing human monocyte/macrophages with bacterial LPS (LPS-MO SN). Monokine induction of ACH-2 cells resulted in augmented virus production reflected by an increase in reverse transcriptase activity and in the synthesis of all major viral proteins. Examination of the cells by indirect immunofluorescence revealed that 10 to 15% of uninduced cells constitutively expressed HIV proteins, whereas 100% showed positive immunofluorescence in response to LPS-MO SN. This induction of virus by LPS-MO SN resulted in approximately a 100-fold increase of infectious virus production over uninduced ACH-2 cells. LPS alone could not induce HIV-1 expression, whereas LPS-MO SN resulted in the greatest virus expression. Cell separation studies confirmed the source of the inducing factor(s) to be cells bearing the mature monocyte/macrophage marker, Leu M3. Biochemical fractionation of the LPS-MO SN suggested that one or more factors, having apparent Mr of approximately 45 kDa, were involved in this induction. Absorption of the LPS-MO SN with immunoaffinity gels specific for human TNF-alpha was shown to completely remove the HIV inducing activity for the ACH-2 cell line.

Biological Factors↗
PubMed1974

Immunoglobulin structure: amino terminal sequences of mouse myeloma proteins that bind phosphorylcholine.

The amino terminal sequences of five light and heavy immunoglobulin chains from myeloma proteins of the BALB/c mouse with binding activity to phosphorylcholine are presented. Except for a single substitution in position 4, all five heavy chains have identical amino terminal sequences through the first hypervariable region. Proteins which share unique (idiotypic) antigenic determinants are identical through the first hypervariable region of their light and heavy chains. Proteins with differing idiotypic determinants have light chains of differing amino acid sequence. These observations suggest that the heavy chain plays a more important role than the light chain in determining the phosphorylcholine binding site.

Amino Acid Sequence↗
PubMed1974

Mouse immunoglobulin heavy chains are coded by multiple germ line variable region genes.

The N-terminal 20 residues of 13 heavy immunoglobulin chains from myeloma protein of the BALB/c mouse are compared with the same residues of 15 other heavy chains described in the literature. Sixteen of 28 sequences are different from one another. These proteins fall into four major sets, with 18 of the proteins in the largest set being further divisible into at least five subsets. This pattern of diversity suggests there are at least eight germ line genes coding for the variable regions of mouse heavy chain. Many of the immunoglobulins from which these heavy chains are derived exhibit binding activity for various haptens. The differing hapten specificities are closely correlated with distinct primary amino-acid sequences.

Amino Acid Sequence↗