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Biomedical subjects

B J Alter

Publications and source records attributed to B J Alter.

At least 37 records · Page 2Linked to original sources
PubMed1979

Lyt phenotypes of responding cells in secondary alloantigen responses.

Lymphocytes responding in a "secondary" MLC-CML system, after in vitro sensitization, apparently fall into two classes with regard to their Lyt phenotype. First, are the cells that form the majority of the proliferating cells after restimulation with either I or K + I differences, which are Lyt 1-2, and second, are Tc that are Lyt 1-2+. The Lyt 1-2- proliferating cells are not cytotoxic and are lysed by treatment with anti-Thy 1.2 serum in the presence of C.

Animals↗
PubMed1979

Past, present, and future aspects of histocompatibility.

We have stressed problems attendant on studies of the MHC, ignoring non-HLA factors and their role in allograft immunity. Many other topics could have been chosen for discussion is any such overview; our selection reflects our own interests. We felt assured, however, that excellent coverage by our many colleagues of the diverse and varied aspects of histocompatibility not approached in this summary has allowed us this freedom.

Cells, Cultured↗
PubMed1978

Alternative pathways of T lymphocyte activation.

Data presented in this paper suggest that there may be two alternative pathways which T lymphocytes can use in generating a cytotoxic response to alloantigens in vitro. First, there is the pathway taken when stimulator and responder cells differ by an entire H-2 complex where Ly1+2- helper T lymphocytes respond to I region encoded lymphocyte defined differences and provide help to the Ly1-2+ cytotoxic T lymphocytes responsive primarily to K/D region encoded cytotoxicity defined determinants. Second, there is the pathway taken when stimulator and responder cells differ by only K or D region differences without an I region encoded difference; under these conditions, an Ly1+2+ cell, which does not appear to play a significant role in the development of a cytotoxic response to an entire H-2 difference, appears to play a pivotal role.

Cytotoxicity, Immunologic↗
PubMed1978

Ultrastructure of effector--target cell interaction in secondary cell-mediated lympholysis.

The ultrastructure of the secondary cell-mediated lympholysis (CML) reaction and the effects on interacting lymphocytes of colchicine, cytochalasin B, and effector cell-specific antisera were examined using transmission and scanning electron microscopy. Surface labelling of cytotoxic secondary effector cells with cationized ferritin allowed them to be distinguished from unlabelled target lymphocytes. Effector--target interactions were characterized by intercellular junctions involving extensive areas of membrane apposition and interdigitation and extension of pseudopod-like processes by the effector cell. The abolition of such interactions when effector populations were pretreated with anti-Ly2 sera plus complement demonstrated target cell destruction in secondary CML to be dependent on the activity of restimulated cytotoxic T lymphocytes. Cytochalasin B and colchicine dramatically decreased the numbers of specific effector--target cell interactions observed. Although the data presented do not allow the possible activity of soluble lytic factors associated with the effector cell surface to be ruled out, they suggest that target cell lysis in the secondary CML system examined results from immune-specific binding of alloantigen-sensitized effectors to targets and osmotic effects which follow localized disruption of the target cell membrane.

Animals↗
PubMed1977

Typing an unrelated panel with PLT cells: association with DW clusters.

Primed LD typing (PLT) cells prepared in one Laboratory (Madison) were shipped in the frozen state and tested in Tübingen on a separate panel that had been typed with homozygous typing cells. Those PLT cells that had been grouped, on the basis of their reaction with test cells of the Madison panel, as defining an HLA PL antigen showed identical or nearly identical patterns of reactivity with the Tübingen panel. Clear association between certain PL antigens and DW clusters as defined with homozygous typing cells could be demonstrated. Of particular interest may be combinations of certain PLT reactions with D-locus-typed cells, where the primed cells do not react as expected from the target's HLA-D type.

Epitopes↗
PubMed1977

Antigenic requirements for the generation of secondary cytotoxicity.

The in vitro role of products of the H-2 complex in restimulation of secondary proliferative and cytotoxic responses has been studied. In this paper we have studied in particular the role of CD antigens, the target antigens for cytotoxic T lymphocytes. We have used UV-treated cells that express their CD antigens but no LD. Like others, we demonstrate that CD antigens alone are able to generate a secondary cytotoxic response and furthermore that these CD antigens must be the same as those used for primary sensitization. However, in contrast to the results of others, in some cases UV-treated cells were unable to restimulate such a response even when appropriate controls showed that the CD antigens on UV-treated cells were functional. Furthermore, in these cases the addition of an LD stimulus in the presence of UV-treated cells results in a secondary cytotoxic response that is significantly greater than that elicited by LD restimulation alone. Such potentiation is not observed if the CD antigens used for restimulation are different from those used for the primary sensitization. In addition, a non-H 2 differences(s), presumably the M1s locus, appears to be able to generate a secondary response. The implication of these results are discussed in terms of "memory" T lymphocytes in cell-mediated immunity.

Animals↗
PubMed1976

Secondary cell-mediated lympholysis: importance of H-2 LD and SD factors.

Lymphocytes stimulated in mixed leukocyte cultures and left for 13-17 days, i.e. beyond their peak proliferative and cytotoxic reactivities, can be restimulated to give a secondary-type rapid and strong proliferative and cytotoxic response when confronted with cells of the original sensitizing cell donor. We have concerned ourselves primarily with the requirements of restimulation for the presence of LD and/or SD stimuli on the restimulating cells. (a) The low level cell-mediated lympholysis (CML) associated with LD differences in a primary CML can be restimulated to give a secondary-type response by those same LD antigens. (b) If the original sensitizing cells differ from the responding cells by both LD and SD antigens, restimulation with only the LD antigens, or third-party cells presumably carrying cross-reactive LD antigens, can restimulate the secondary CML responses directed against the SD antigens on the original sensitizing cells. (c) The presence of SD antigens on the restimulating cells that are cross-reactive with the primary sensitizing SD antigens (as determined in a primary CML) leads to the preferential activation of cytotoxic T lymphocytes reactive to those antigens although maximum cytotoxicity is still directed at cells carrying the original sensitizing SD antigens. A model to explain these results is presented.

Animals↗
PubMed1975

Genetic and cellular control of in vitro models of allograft reactivity.

In each species sufficently studied, a single genetic region, the major histocompatibility complex (MHC), controls the strong transplantation antigens. Recent evidence suggests that the genetic control of differences important in allograft phenomenon is more complex than previously realized. In addition to the two loci, alleles of which control serologically defined (SD) antigens, there are other loci the phenotypic products of which lead to T-lymphocyte activation in mixed leukocyte culture. These latter loci have been referred to as LD (or lymphocyte defined). There appears to be a physiologic interaction between these two loci in that the LD differences seem to be important in the initial recognitive phases of the allograft reaction; the SD differences (or products of genes very closely linked to those determining the SD antigens) are important as a target for cytotoxicity as studied by the cell-mediated lympholysis test.

Animals↗