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Biomedical subjects

H Waldmann

Publications and source records attributed to H Waldmann.

At least 361 records · Page 20Linked to original sources
PubMed1980

Differences in calcium requirements for B-cell tolerance and immunity.

Incubation of unprimed spleen B cells with high concentrations of hapten-conjugates resulted in the induction of specific unresponsiveness or tolerance to a subsequent encounter with the hapten on a potentially immunogenic carrier. This process of tolerance induction could occur in the absence of extracellular calcium. In contrast B-cell activation to both proliferation and subsequent antibody secretion is known to be calcium dependent. This means that either (1) the decisions which determine immunity and tolerance in B cells are mediated through totally distinct signalling pathways, or that (2) if tolerance and immunity depend on same common signalling events, then the commitment of B cells to switch on or off must be determined at a very early stage.

Animals↗
PubMed1977

Can B-cell tolerance be induced by oligovalent thymus dependent antigens?

Spleen cells from adult mice were rendered "tolerant" to TNP by exposing cells in vitro to large concentrations of TNP10BSA. After such treatment the residual response to TNP was measured using TNP-LPS as antigen in vitro or in vivo. The "tolerance" observed in this system was not reversed by treating the cells with trypsin, nor by using non-specific polyclonal activators. Furthermore, responsiveness to TNP-LPS in vitro was not substantially restored when such "tolerant" cells were "parked" in vivo for 7 days. In contrast when TNP-KLH was the antigen used to challenge TNP-BSA treated cells, no unresponsiveness was observed. The results are discussed in terms of the degree of thymus dependence of the challenge antigens; subpopulations of B cells, and current hypotheses of B-cell activation;

Animals↗
PubMed1977

Co-operation across histocompatibility differences. The role of inhibitory T cells in preventing successful T-B interaction.

The efficiency of interaction of helper T cells with memory B cells of varying histocompatibility types has been studied in an in vitro microculture system. Such studies show that I-A region matching does not necessarily determine that efficient co-operation will take place. Failure to co-operate under circumstances where T and B cells match in I-A can be attributed to radiosensitive suppressor T cells. The nature of the gene differences which provoke the activity of such suppressor cells have also been examined, and it would seem that even single S.D. differences in the MHC are sufficient to generate 'suppressor' T-cell activity.

Animals↗
PubMed1977

Heterogeneity of B cells reacting with T-cell factors. Evidence for matching T-cell and B-cell subsets.

Spleen T cells have been stimulated with Concanavalin A (Con A) under conditions which lead to the production of non-specific factor (NSF), a substance which replaces T cells for B-cell responses to certain antigens. We have examined the ability of multiple aliquots of B cells to react to the NSF derived from single T cells, and have found great heterogeneity of response. We postulate that there exist subsets of T cells which vary in either the quantity or the quality of the non-specific factor(s) they can produce on stimulation, and that in turn there must also be matching subsets of B cells which may vary in their susceptibility to such factors.

Animals↗
PubMed1977

The influence of antigen presentation on the generation of T-helper cells with different functions.

Thymocytes adoptively transferred into syngeneic irradiated recipients can be primed with antigen (KLH) to generate two types of helper function termed 'specific' and 'non-specific'. Low doses of KLH given without adjuvant generate high levels of non-specific compared to 'specific' helper T cells. Large doses of KLH given in adjuvant (FCA) generate high levels of both types of helper T cell. Explantations for this observation are discussed.

Animals↗
PubMed1976

Cooperation across the histocompatibility barrier: H2d T cells primed to antigen in an H-2d environment can cooperate with H-2k B cells.

H-2d spleen cells derived from either tetraparental or semiallogeneic radiation bone marrow chimeras can be primed to antigen within H-2d recipients to generate helper T cells capable of cooperating in a secondary response with equal efficiency with H-2d or H-2k B cells. Thus it would seem that the cooperative act between T and B cells does not require that the T cell interacts with its target B cells by either cell interaction genes or via an altered self mechanism involving both antigen and the target B-cell I-region products. This does not preclude a requirement for associative recognition or altered self in the interaction of helper T cells with accessory cells.

Animals↗
PubMed1976

[Agreement between traditional and computer diagnosis in psychiatric outpatients (author's transl)].

Psychiatric diagnosis based on personal interviews with 100 clinic outpatients was made and the data thus obtained were documented in Spitzer's and Endicott's CAPPS (Current and Past Psychopathology Scales). Two clinicians and the computer program DIAL - a modification of the DIAGNO II program of the same authors - diagnosed the same patients independently of each other basing their diagnoses solely on the entries in the CAPPS. The diagnostic agreement between the different diagnoses was evaluated and results compared with earlier findings by Schmid et al. These authors had, however, used CAPPS data gathered from case histories and not from direct interviews of patients. The modification in the procedure of gathering the data resulted in a slight, but statistically insignificant improvement in diagnostic agreement. The possibility of improving diagnostic agreement by the use of another scale is discussed.

Ambulatory Care↗
PubMed1976

Antigen-non-specific T-cell factor in B-cell activation. Origin, biological properties and failure to show a relationship to H-2.

A population of T cells sensitive to ALS treatment release a non-specific factor (NSF) capable of replacing T cells in the response of nude spleen cells to erythrocyte antigens. This factor cannot be removed by immunoadsorbents with specificities directed towards products of the H2 complex, nor by lentil lectin, unlike certain specific T-cell factors. Furthermore, it functions across histocompatibility differences between mouse strains. It has been directly demonstrated that this factor can influence both proliferation and differentiation of B cells in response to a restricted group of T-dependent antigens, of which donkey and sheep erythrocytes are such special cases.

Animals↗
PubMed1976

Limiting dilution analysis of helper T-cell function. II. An approach to the study of the function of single helper T cells.

Procedures have been described which are suitable for experiments utilizing a microculture system whereby one can easily study the function of single helper T cells. These are: (a) the elimination of the background anti-hapten response by preliminary anti-theta + guinea-pig complement complement treatment of the 'hapten-primed' population; (b) the removal of any contaminating hapten-specific B cells from the carrier-primed population by passage through nylon wool; (c) irradiation of long-term primed 'nylon wool' enriched helper cells tp prevent cell division; (d) the partition of individual helper cells by limiting dilution.

Animals↗
PubMed1976

Restriction in the function of single helper T cells.

T cells involved in specific and nonspecific co-operation belong to a long-lived population. However, under conditions of limiting dilution of T cells it is not a common event to detect both types of co-operative event in a single microculture well. Likewise, as far as specific co-operation is concerned, the simultaneous expression of both direct and indirect PFC responses in a single microculture well is also unusual. Estimates obtained of the number of PFC generated by one T cell in specific co-operation correspond well to those generated by a single B cell; and it would seem that under conditions of the microculture system there is a marked restriction in the number of B cells that a single T cell may interact with in the short term. This restriction seems to be of a one T-cell to one B-cell relationship.

Animals↗