Biomedical subjects

J J Neefjes

Publications and source records attributed to J J Neefjes.

60 records · Page 4Linked to original sources

PubMed1988

Recycling glycoproteins do not return to the cis-Golgi.

Recycling of a number of glycoproteins along the site of action of mannosidase I (the distal endoplasmic reticulum/cis-Golgi) was followed in several different cell lines. Treatment of cells with 1-deoxymannojirimycin (dMM) produced high mannose oligosaccharides at positions otherwise occupied by complex-type oligosaccharides in these glycoproteins. Conversion of high-mannose-type oligosaccharides to complex oligosaccharides of proteins initially synthesized in the presence of dMM was used as a marker for recycling of glycoproteins along the site of action of dMM. In contrast to findings reported by Snider and Rogers (Snider, M. D., and O. C. Rogers. 1986. J. Cell Biol. 103:265-275), removal of dMM did not result in reconversion of high-mannose oligosaccharides to complex-type sugars, even after prolonged periods of culture. We conclude that surface glycoproteins do not recycle through the cis-medial Golgi elements.

1-Deoxynojirimycin↗

PubMed1987

Association with beta 2-microglobulin controls the expression of transfected human class I genes.

The genes encoding HLA-B27K and HLA-B27W were transfected into murine recipient cells. A monoclonal antibody HC-10, directed against free B-locus heavy chain, was the only reagent capable of efficiently detecting the HLA-B27 heavy chains in detergent lysates. These heavy chains were devoid of sialic acid. Trace amounts of HLA-B27 could be isolated with the anti-HLA-A,-B antibody W6/32, which reacts with the heavy chain beta 2-microglobulin complex. In marked contrast, HLA-A2 and -B7 genes, when transfected, yielded easily detectable amounts of antigen precipitable with W6/32, which carried the usual complement of sialic acids. Because the alpha 3 domains of HLA-B27 and HLA-B7 and the more COOH-terminal portions are identical in amino acid sequence, structural elements in the polymorphic alpha 1 and alpha 2 domains must control association of heavy chain with beta 2-microglobulin. Introduction of a human beta 2-microglobulin gene into L cells transfected with the HLA-B27 gene rescued the expression of HLA-B27 at the cell surface, as evidenced by reactivity with W6/32, surface staining, and the presence of sialic acid on the heavy chain.

Animals↗

PubMed1986

An analysis of class I antigens of man and other species by one-dimensional IEF and immunoblotting.

A procedure for the molecular identification of MHC class I products based on 1-D IEF and subsequent immunoblotting is described. Optimal conditions for 1-D IEF, the electrophoretic transfer of proteins out of denaturing, nonionic detergent-containing gels to nitrocellulose, and the requisite antibodies, both polyclonal and monoclonal, for the visualization of class I heavy chains have been established. Cross-reactivity of antibodies has enabled the biochemical analysis of class I heavy chains in the dog. The procedure reported here requires modest amounts of cells and allows a rapid molecular characterization of class I heavy chain polymorphisms in man and other species without the need for radiochemical methods.

Animals↗

PubMed1986

A biochemical characterization of feline MHC products: unusually high expression of class II antigens on peripheral blood lymphocytes.

The polymorphism of feline MHC antigens was examined using biochemical methods. The following observations were made: (1) feline class I and II antigens are polymorphic. Their biochemical features were established using rabbit and mouse reagents directed against human MHC products; they resemble those observed for other mammalian species; (2) the expression of class II antigens in unstimulated cat peripheral blood lymphocytes (PBLs) appears to be unusually high. Cat PBLs express far more class II than class I antigens, whereas in human Epstein-Barr virus-transformed lines, which are known to express relatively large amounts of class II antigens, the situation is reversed.

Animals↗

PubMed1986

An improved biochemical method for the analysis of HLA-class I antigens. Definition of new HLA-class I subtypes.

A simple method is described for the biochemical analysis of HLA class I antigens. It is a modification of a previously published procedure for one-dimensional isoelectric focusing (1D-IEF), giving improved resolution and offering larger sample capacity. One million viable cells suffice for analysis, and no more than 25 muCi of radioisotope (35S-methionine) are required. The usefulness of the method is illustrated by the characterization of a total of four biochemically distinct subtypes of HLA-B27, three subtypes of HLA-A24, two subtypes of HLA-A11, three subtypes of HLA-A2, two subtypes of HLA-Bw60, two subtypes of HLA-Bw62, and four subtypes of HLA-B35 in a panel of 24 cells selected for the expression of HLA-B27. We envision that this technique will allow a rigorous classification of HLA-A,B antigens into novel subtypes. Populations of distinct ethnic origin are especially of interest in this regard. This technique might also be used as an additional criterion for the official classification of HLA-A,B antigens.

HLA Antigens↗

PubMedDate not supplied

Interference with HIV-induced syncytium formation and viral infectivity by inhibitors of trimming glucosidase.

Human immunodeficiency virus (HIV), the causative agent of AIDS, infects human lymphocytes and monocytes. An interaction between the viral envelope gp 120 and CD4 protein is required to initiate an infectious cycle. HIV infection in vitro induces syncytium formation by cell-to-cell fusion; this aspect of viral cytopathogenicity is even more dependent on gp120-CD4 interactions. That gp120 is extremely heavily glycosylated (31-36 N-linked glycans per molecule), suggests involvement of N-linked glycans in the gp120-CD4 interaction. We therefore investigated the effects of castanospermine, 1-deoxynojirimycin (dNM) and 1-deoxymannojirimycin (dMM), three trimming glycosidase inhibitors which perturb N-linked glycan structure, on induction of the formation of syncytium between HIV-infected and CD4-expressing cells. The glucosidase inhibitors castanospermine and dNM, but not the mannosidase inhibitor dMM, inhibited syncytium formation and interfered with infectivity. The potential of glucosidase inhibitors as anti-HIV therapeutic agents deserves further investigation, especially because dNM and related compounds show little toxicity in vitro and in vivo.

1-Deoxynojirimycin↗