Showing papers by "Per A. Peterson published in 1974"

Highly Purified Papain-Solubilized HL-A Antigens Contain β2-Microglobulin

Abstract: HL-A antigens comprising 11 different antigenic specificities were isolated after papain solubilization of spleen-cell membrane constituents. During the entire purification procedure, β2-microglobulin appeared together with the HL-A antigens. The highly purified antigens were composed of two polypeptide chains. The large subunit carried the antigenic specificity whereas the small polypeptide chain was very similar, if not identical, to β2-microglobulin. The two HL-A antigen polypeptide chains were held together by noncovalent interactions only, and β2-microglobulin, isolated from urine, could replace the small subunit in forming a complex with the large polypeptide chain. The topographical relationship in the cell membrane between β2-microglobulin and the large HL-A antigen polypeptide chain is unknown. The two polypeptide chains may be fortuitously bound as a result of the solubilization procedure.

Aspects of the metabolism of retinol-binding protein and retinol.

Abstract: Publisher Summary This chapter presents different aspects of the metabolism of retinol-binding protein (RBP) and retinol. RBP is not significantly decreased until the liver reserves of the vitamin are virtually abolished. The diminished concentration of RBP in plasma in manifest vitamin A deficiency reflects the impaired transport of retinol to the various tissues. The catabolism of RBP is probably greatly dependent on renal function, since a small fraction of free RBP exists in plasma although most is bound to prealbumin. The biological half-life of RBP was increased by about 50% in protein deficiency while the rate of synthesis was diminished to one-third of the normal value. The cellular accumulation of retinol is a temperature-dependent process. Incubations of the cells in the absence of oxygen or in the presence of metabolic inhibitors like sodium azide and EDTA did not change their ability to extract retinol from RBP. It is seen that the labeled RBP component exhibited a slower electrophoretic mobility than genuine RBP, which could complex with prealbumin. The low pH was chosen to minimize charge differences due to variable content of amide groups in the two forms of RBP.

Subunit structure of H-2 alloantigens.

Abstract: HISTOCOMPATIBILITY antigens carry the immunological determinants involved in tissue transplant rejection1. Recent evience has shown that papain-solubilised HL-A antigens are composed of two polypeptide chains2,3. The smaller of the solubilised HL-A polypeptide chains has been shown4,5 to be identical to β2-microglobulin and it has also been shown that β2-microglobulin is physically linked to the HL-A antigens on the cell surface6–9. These findings raised the question of whether the major transplantation antigens from other species are composed of subunits. This communication shows that mouse H-2 alloantigens are linked to a small polypeptide chain which is homologous with human β2-microglobulin.

Subunit structure of HL-A antigens on cell surface.

Abstract: THE major human histocompatibility determinants, the HL-A antigens, are cell surface markers present on lymphocytes and most other nucleated cells (compare ref. 1). Recently, work from two laboratories has indicated that HL-A antigens, released from the cell surface by means of papain digestion, are composed of two polypeptide chains2,3. The smaller of the two subunits seems to be invariant regardless of the antigenic specificity carried by the larger HL-A chain2,3 and occurs in human biological fluids4.

The subunit structure of transplantation antigens.

Abstract: Molecular structures present on the cell surface constitute antigenic markers of great importance for the biological integrity of the individual. The major human histocompatibility antigens (HL-A) are serologically defined antigenic determinants present on leucocytes and other nucleated cells. In the mouse, strong as well as weak histocompatibility antigen systems have been found. One of these systems, H-2, plays a major role in transplantation survival and has genetical similarity to the HL-A system in man. Several excellent reviews on the genetic organization of the major histocompatibility complex in man and in mouse have recently been published (Demant 1973, Thorsby 1974). Various methods have been used to solubilize cell surface-bound glycoproteins with serological HL-A and H-2 activity. The methods used involve proteolytic treatment with papain, sonication, or extraction with high concentrations of salt (Davies 1967, Reisfeld et al. 1971, Kahan & Reisfeld 1969). Papain-solubilization of HL-A antigens gives products of a fairly distinct molecular size which appear suitable for chemical characterization. Recent studies have revealed that papain-solubilized HL-A antigens are composed of two polypeptide chains, one carrying the serological activity and the other without serolo^cally detectable HL-A antigenic determinants (Cresswell et al. 1973, Tanigaki et al. 1973, Tanigaki et al. 1974). The latter of the two polypeptide chains had an estimated molecular weight of 10,000 12,000, and ocurred in serum and urine.