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L A Lampson

Publications and source records attributed to L A Lampson.

47 records · Page 3Linked to original sources
PubMed1983

Striking paucity of HLA-A, B, C and beta 2-microglobulin on human neuroblastoma cell lines.

Monoclonal antibodies to beta 2-microglobulin (beta 2m), and to the native two-chain molecule, were used to assess the expression of the HLA-A, B, C molecules on human neuroblastoma-derived cell lines. In radioimmuno-, cytotoxic, and microscopic assays, employing fresh and fixed cells, neuroblastoma cells show at best weak activity as compared to glial or lymphoid cells. In binding inhibition assays, neuroblastoma extracts were 200- to 1800-fold less efficient in inhibiting the antibodies than were glial or lymphoid extracts. Immunoprecipitation and SDS-PAGE analysis confirmed that a beta m-like chain is synthesized by the neuroblastoma cells, but the HLA chain could not be visualized by this technique. HLA-A, B, C and beta 2m levels are known to vary among tissues and cell lines. Yet the magnitude of the differences between the neuroblastoma and lymphoid lines is much greater than the reported differences in expression between some of these same lymphoid lines and many other nonlymphoid malignant or nonmalignant cell types. Metastatic neuroblastoma tumor in bone marrow also showed weak HLA-A, B, C activity, with the cells appearing negative in microscopic assays. Possible clinical implications are discussed.

Animals↗
PubMed1983

Separation of three class II antigens from a homozygous human B cell line.

Three class II molecules were isolated from a homozygous DRw6 human B lymphoblastoid cell line using the monoclonal antibodies L243 (L203), L227, LKT 111, and Genox 3.53. Two of the antigens appeared to employ the same heavy chain but expressed different light chains. The two light chains were separated after denaturation using L227 and LKT 111. One or both of these two molecules carried the DRw6 and MT2 determinants. The third class II antigen expressed the DC1 determinant. It was composed of a heavy and light chain different from the DR-like antigen subunits. The antibodies L243, L227, and LKT 111 did not preclear the cell lysate of the DC1 antigen recognized by Genox 3.53. However, a xenoanti-DR serum immunoprecipitated both the DR-like and the DC1 antigens. Thus, in total, one cell line can express at least two class II heavy chains and three class II light chains. This observation was not unique to this cell line.

Antibodies, Monoclonal↗
PubMed1982

Serologic identification of the human secondary B cell antigens. Correlations between function, genetics, and structure.

The secondary B cell (SB) antigens are polymorphic HLA-linked antigens on human B cells and macrophages that are identified by primed T cell responses but are genetically distinct from the HLA-DR, MB, and MT antigens. Serologic identification of the SB molecule, using the monoclonal antibody ILR1, now makes it possible to correlate the function of these determinants in human T cell recognition with an Ia-like molecular structure and a genetic locus that marks a new HLA subregion. Three lines of evidence indicate that the ILR1 molecule identifies an epitope on some alleles of the SB gene: (a) the polymorphism of ILR1 -reactivity in the population correlates with SB2 SB3; (b) T cell proliferative response to SB2 and SB3 are specifically inhibited by ILR1; and (c) ILR1 reactivity is exactly concordant with the expression of SB2 in a panel of HLA-deletion mutant lymphoblastoid cell line. Together with previous studies, these results indicate that the SB antigens are on Ia-like molecules. Furthermore, the serologic studies of HLA-deletion mutant cell lines demonstrate that there are two HLA regions centromeric to HLA-B controlling expression of Ia-like molecules: a region toward HLA-B that controls expression of HLA-DR, and a region toward GLO that controls expression of SB.

Antibodies, Monoclonal↗
PubMed1981

Analysis of HLA-DR antigens by using monoclonal antibodies: recognition of conformational differences in biosynthetic intermediates.

The monoclonal antibodies L203 and L227 were used to characterize Ia-like antigens on human B cell lines. The antibodies appear to recognize subsets of HLA-DR molecules on the cell line Raji, which is heterozygous for HLA-DR. However, by using L203 and L227, more than 1 DR-like molecule could not be clearly identified on the DRw8 homozygous cell line MADURA. The 2 antibodies did display different affinities for different forms of the same DR molecule. On DRw8 and cell lines of other DR types, L227 had a greater affinity than L203 for the biosynthetic intermediates of the DR heavy and light chains. L203 displayed a greater affinity than L227 for the mature forms of the DR subunits. The antibody L227 immunoprecipitated the denatured DR light chain, but not the heavy chain, suggesting that the antigenic determinant is on the light chain. The L203 and L227 determinants are not on the N-linked oligosaccharides, since both antibodies recognized nonglycosylated DR antigens from cells treated with tunicamycin. In contrast to the DRw8 homozygous cell line, it was found that DRw6 homozygous B cell lines express at least 2 DR light chains. A xeno anti-HLA-DR (anti-p23,30) serum and L203 recognized both light chains, whereas L227 precipitated only 1 of the 2. A model depicting the expression of the L203 and L227 antigenic determinants on the DRw8 molecule is discussed.

Antibodies, Monoclonal↗
PubMed1980

Two populations of Ia-like molecules on a human B cell line.

Evidence is presented for two populations of Ia-like molecules on the human B cell line Raji. Two monoclonal antibodies, L203 and L227, are described. Both recognize nonpolymorphic determinants on B cell antigens. Both immunoprecipitate 34,000- and 28,000-dalton material from 125I-labeled extracts of Raji, but L227 precipitates 25,000-dalton material as well. Immunodepletion experiments confirm that the antibodies react with two different populations of molecules.

Antibodies↗
PubMed1977

Homogeneous antibodies directed against human cell surface antigens: I. The mouse spleen fragment culture response to T and B cell lines derived from the same individual.

The use of the mouse spleen fragment culture system is extended to the production of antibodies to human lymphoblastoid cell lines. These antibodies were tested for reactivity against the immunizing cell line, and against a second cell line which had been derived from the same human blood sample. Many of the antibodies were found to discriminate between the 2 isogenic lines. These results demonstrate the potential of the mouse spleen fragment culture system to provide homogeneous reagents which detect distinguishing markers on closely related human cells.

Animals↗
PubMedDate not supplied

MHC expression in nonlymphoid tissues of the developing embryo: strongest class I or class II expression in separate populations of potential antigen-presenting cells in the skin, lung, gut, and inter-organ connective tissue.

We define expression of major histocompatibility complex (MHC) antigens in the nonlymphoid tissues of the developing rat. Antibodies to class I heavy and light chains (b2-m), and to class II MHC proteins were used. Strongest MHC expression was by individual cells in the skin, lung, gut, and inter-organ connective tissue. The class I+ and class II+ cells were distinct populations, differing in morphology, distribution, and expression of macrophage-associated antigens. A nonimmunologic role for MHC proteins in development has been proposed. Yet the distributions and antigenic profiles lead us to emphasize immunologic functions that may be served by the early presence of MHC+ cells outside the forming lymphoid organs. Potential contributions to establishment of extrathymic or maternal/fetal tolerance are discussed. Localization of strongest MHC expression to individual connective tissue cells of the developing organs, rather than parenchymal cells, is of clinical relevance to transplantation of fetal tissue.

Animals↗