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A Schimpl

Publications and source records attributed to A Schimpl.

35 records · Page 2Linked to original sources
PubMed1979

Studies on the generation and expression of H-2-controlled T helper function in chimeric mice: evidence for two levels of H-2 resitriction.

F1 leads to parental, semisyngeneic/semiallogeneic and fully allogeneic bone marrow radiation chimeras were used as a source of helper T cells in the in vitro anamnestic response to dinitrophenylated keyhole limpet hemocyanin. In F1 leads to parental and in semisyngeneic/semiallogeneic chimeras, a small population of helper T cells restricted to the H-2 haplotype present in the donor only was shown to co-exist with T cells restricted to the shared haplotype. Only the population restricted to the donor H-2 could be demonstrated in allochimeras, presumably due to a lack of antigen-presenting cells of host origin during priming. Under assay conditions where, in addition to T cell/macrophage interactions, a direct T-B cell contact was necessary ("linked" cooperation), the H-2 restrictions observed were absolute. When direct T-B cell contact was made unnecessary by a special experimental protocol ("unlinked" cooperation), H-2 restriction between T and B cells was overcome. Thus, the cellular interactions during the anamnestic immune response to T-dependent antigens seem to be H-2-restricted at two levels: T cell/macrophage and T-B cell interactions.

Animals↗
PubMed1979

Purification and characterization of a mitogenic lectin and a lectin-binding protein from Vicia sativa.

From the seeds of Vicia sativa, a novel mitogenic lectin was isolated. Purification was carried out by affinity chromatography on Sephadex G-100. The tetrameric lectin is a glycoprotein with a molecular weight of Mr 40 000; it consists of two large beta-subunits (Mr 14 000) and two small alpha-subunits (Mr 6000). The N-terminal sequence of both subunits and their amino acid compositions were determined. The lectin agglutinates human erythrocytes, preferring group B, and erythrocytes from rabbits and horses; no agglutination takes place with sheep erythrocytes. Agglutination is inhibited by mono-, di- and tri-saccharides with the configuration of glucose at the free 4-hydroxyl group. The lectin stimulates mitosis in lymphocytes of mice. From the seeds of the same plant, a protein was isolated which binds to the lectin described above. The lectin binder consists of subunits with a molecular weight of 53 500.

Amino Acid Sequence↗
PubMed1977

Mechanism of T-cell help in the immune response to soluble protein antigens. I. Evidence for in situ generation and action of T-cell-replacing factor during the anamnestic response to dinitrophenyl keyhole limpet hemocyanin in vitro.

The involvement of a nonantigen-specific T-helper factor in the anamnestic immune response to dinitrophenyl keyhole limpet hemocyanin is demonstrated employing cultures of unseparated spleen cell populations. In such cultures of primed and boosted spleen cells, a good IgG anti-DNP response could be obtained if the hapten was presented on a heterologous carrier, provided that the homologous carrier was added simultaneously. T-cell depletion and reconstitution experiments show that such a factor, presumably identical with T-cell-replacing factor is produced by primed helper cells upon rechallenge and helps primed B cells, stimulated by soluble heterologous carrier hapten conjugates, to become IgG-secreting cells.

Animals↗
PubMed1977

Mechanism of T-cell help in the immune response to soluble protein antigens II. Reconstitution of primary and secondary in vitro immune responses to dinitrophenyl-carrier conjugates by T-cell-replacing factor.

Spleen cells of dinitrophenyl keyhole limpet hemocyanin (DNPKLH) primed and boosted mice produced a nonantigen-specific helper factor upon in vitro challenge with DNPKLH. This helper factor displays all of the biological characteristics so far described for TRF produced by allogeneic or Concanavalin A stimulation of mouse spleen cells. It restores the primary anti-SRBC response in nude spleen cultures following the same kinetics of action as T-cell-replacing factor (TRF). Conversely, TRF restores the primary in vitro immune response of nude spleen cultures to DNPKLH. TRF also restores the secondary anti-hapten IgG response of T-cell-deprived spleen cell cultures derived from DNPKLH primed and boosted mice. Here the need for carrier specificity is fully overcome. The data therefore suggest that TRF, as a nonantigen-specific maturation signal, is involved in the primary and secondary immune responses to both particulate and soluble antigens.

Animals↗
PubMed1974

Autoradiographic studies on the proliferation of antibody-producing cells in vitro.

A rapid and reliable autoradiographic technique for plaque-forming cells (PFCs) using (14)C rather than tritiated thymidine is described. Its application to PFCs developing in vitro shows that (a) practically all PFCs derive from precursors dividing steadily during the culture period, (b) PFC precursors divide in the absence of T-cell helper function, and (c) at least some PFCs may continue to divide.

Animals↗
PubMed1973

Stimulation of IgG antibody response in vitro by T cell-replacing factor.

A soluble factor (TRF) produced by mixtures of allogeneic mouse spleen, lymph node, and thymus cells functionally replaces T cells in a primary IgM antibody response to sheep blood cells in vitro. It is now shown that TRF can also reconstitute an IgG antibody response in T cell-deprived spleen cultures derived from preimmunized mice. The optimal time of addition and the amount of TRF required differ between primary and secondary in vitro systems.

Animals↗