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L Adorini

Publications and source records attributed to L Adorini.

14 recordsLinked to original sources
PubMed1979

Lysozyme-induced T-suppressor cells and antibodies have a predominant idiotype.

The existence of shared idiotypic determinants on the surfaces of T and B cells is now firmly established, suggesting that on both these cell types immunoglobulin variable regions are expressed which presumably function as antigen receptors. In most systems this has been inferred through the use of anti-idiotypic antibody instead of antigen to induce either helper or suppressor T cells. Recent evidence demonstrates that antigen-specific suppressor or helper factors can also bear idiotypic determinants. It is possible that these factors represent released receptors or portions of receptors. We show here the direct elimination of an antigen-induced T-suppressor population by an anti-idiotypic serum and complement. These suppressor T cells as well as the idiotypic population used to generate the antiserum are each specific for the same limited portion of the multi-determinant antigen, lysozyme. Apparently, these suppressor cells are restricted in specificity as well as share idiotypy with antibodies of the same specificity.

Animals↗
PubMed1979

Fine specificity of regulatory T cells. II. Suppressor and helper T cells are induced by different regions of hen egg-white lysozyme in a genetically nonresponder mouse strain.

We have examined the ability of two purified peptide fragments derived from hen (chicken) egg-white lysozyme (HEL); N-terminal, Co-terminal peptide (a.a. 1--17:cys 6--cys 127:120--129) and mixed disulfide LII peptide (LII) (a.a. 13--105) to induce antigen-specific suppression or help in B10 (H-2b) nonresponder and B10.A (H-2a) responder mice. An anti-HEL primary in vitro antibody response can be obtained in either strain by stimulation with HEL coupled to erythrocytes (RBC). Preimmunization with HEL-complete Freund's adjuvant-(CFA) or N-C-CFA-induced suppression of the anti-HEL PFC response to HEL-RBC in spleen cell cultures from B10 mice, whereas helper activity was demonstrated in cultures from B10.A mice similarly immunized. LII-CFA priming elicited helper cells in both C57BL/10 Sn (B10) and B10.A/SgSn (B10.A) mice. The genetic nonresponsiveness of B10 mice to HEL can therefore be attributed to the activation of suppressor T cells by a limited portion of the molecule (e.g., N-C) which prevent the potential response directed against other epitopes on the same molecule (e.g., LII). One manifestation of major histocompatibility complex gene activity appears to be the intramolecular selection of different antigenic determinants leading to activation of functionally different T-cell subpopulations.

Amino Acid Sequence↗
PubMed1979

The fine specificity of regulatory T cells. IV. Idiotypic complementarity and antigen-bridging interactions in the anti-lysozyme response.

The hen egg-white lysozyme (HEL)-specific B cells which are activated in response to HEL share a cross-reactive idiotype as well as submolecular specificity. Helper T cells of two different specificities are implicated in their optimal activation, one recognizing the idiotype and the other, an epitope on the HEL molecule opposite to the one recognized by B cells. Thus, efficient T-B collaboration involves both idiotypic complementary and antigen bridging.

Animals↗
PubMed1978

A miniaturized in vitro diffusion culture system.

A miniaturized diffusion culture apparatus holding 24 individual cultures and utilizing 1/10 the cells and volume of standard Marbrook-type cultures is described. This system was evaluated by studying the anti-sheep erythrocyte response of spleen cells from unprimed or primed and boosted mice. Compared to parallel Mishell--Dutton plate cultures memory responses in mini-diffusion cultures rise more slowly, peak 1--2 days later and thereafter decline less rapidly. Moreover, the diffusion cultures give a pronounced IgG response peaking at 6 days, while the abortive IgG response evident in plate cultures at 4 days rapidly disappears. While viability in the two systems is equivalent, cell recovery on days 7 and 8 is markedly higher in the diffusion cultures. Of 4 cell concentrations tested, 2 million cells are found to produce the optimum anti-sheep erythrocyte plaque-forming cell response. A 0.2 micron nucleopore membrane is preferable to a dialysis membrane and yields up to a 2-fold higher response. Replacement of the reservoir medium on day 4 impairs rather than improves the response. The culture system was also found to support an excellent primary response. This response is dependent on the presence of 2-mercaptoethanol and does not require rocking.

Animals↗
PubMed1977

Effects of whole-body irradiation on antibody affinity.

Mice exposed to a sublethal dose of X-rays were immunized with alum-precipitated DNP-KLH (dinitrophenyl-keyhole limpet haemocyanin) and B. pertussis either before or after irradiation. The primary anti-DNP antibody response was evaluated during 8 weeks after immunization by the equilibrium dialysis technique using ammonium sulphate- precipitated serum globulins and the ligand 3H-labelled xi-DNP-L-Lysine. The serum concentrations of antibody sites in mice immunized 1-5 days before or 2 h-8 weeks after 450 rad were below the values in unirradiated controls at all bleeding times. Antibody affinity, however, was found to be up to 20 fold higher in irradiated mice than in control mice when antigen was injected before, or 3-8 weeks after, irradiation. Spleen cells from mice exposed to 450 rad 1-9 weeks before killing were stimulated in vitro with PHA, ConA, or LPS. Recovery profiles of mitotic responsiveness suggest that enhancement of antibody affinity in irradiated mice could result from relative lack of suppressor T Cells.

Animals↗
PubMed1976

Cell selection in the thymus of mice treated with escherichia coli lipopolysaccharide (LPS).

The present data indicate that injection of LPS induces a decrease in thymus weight with selection of thymocytes more efficient in killer and helper activities. It has been reported (12) that two T-cell types may cooperate in the GVH reaction: the effector T1 and the amplifier T2. The maturation from T1 to T2 occurs mainly in the periphery, whereas immature cortex thymocytes differentiate to T1 within the thymus (13). Our results, showing an LPS-dependent enhancement of thymocyte killing activity, suggest that LPS selects thymocytes mostly of the T1 type. LPS-treated thymocytes are more efficient in the reconstitution of the anti-SRBC response. These data can be explained considering that LPS, like cortisone (14), enriches the thymus with more immunocompetent helper cells. Alternatively it may be suggested that LPS selects in the thymus cell populations characterized by high proliferative activity. Unpublished observations showing that LPS-treatment in vivo increases the in vitro response of thymocytes to Con-A are consistent with this interpretation.

Animals↗
PubMed1976

Immune responsiveness and incidence of reticulum cell sarcoma in long-term syngeneic radiation chimeras.

Long-term syngeneic radiation chimeras displayed a very low incidence of reticulum cell sarcoma as compared with control mice. Immune reactivity of these animals was studied in vivo by anti-dinitrophenyl antibody titer and affinity and in vitro by mitotic responsiveness to phytohemagglutinin, concanavalin A and lipopolysaccharide. Anti-body titer and affinity as well as the response to T lectins were found to be increased in chimeras. These results were attributed to increased function of mature T2 cells, which could explain the reduced incidence of reticulum cell sarcoma in chimeras.

Animals↗
PubMed1976

Biological effects of Escherichia coli lipopolysaccharide (LPS) in vivo. II. Selection in the mouse thymus of PHA- and con A-responsive cells.

The effect of LPS injection on mouse thymocytes was examined by in vitro stimulation with PHA and Con A. Thymocytes from LPS treated mice were found more responsive than normal thymocytes to PHA and Con A. The increase of responsiveness was different for PHA and Con A, and dependent on the dose of LPS injected. This dose dependency suggests that LPS in vivo modifies the thymocyte population by progressively eliminating T1 cells and selecting T2 cells. These effects seem to be mediated by corticosteroids because they were prevented by adrenalectomy, a finding in agreement with the notion that the injection of cortisone induces similar cell changes in the thymus.

Adrenalectomy↗
PubMed1976

Biological effects of Escherichia coli lipopolysaccharide (LPS) in vivo. I. Selection in the mouse thymus of killer and helper cells.

In the present study we have investigated the biological effects on thymus lymphocytes resulting from Escherichia coli lipopolysaccharide (LPS) treatment in young adult mice. It has been established that LPS induces the following effects: (a) a dose-dependent reduction of thymus weight contemporaneous with a rise in the anti-LPS antibody response; (b) an increase of killer activity of thymus cells; (c) an enhancement of thymocytes helper activity; (d) a reduction of theta-positive cells in the thymus; (e) a cellular depletion in the thymus cortex. These data, indicating that LPS selects in the thymus a population of cells more efficient in expressing both killer and helper functions, are interpreted as caused by an increased rate of cortisol secretion induced by the LPS treatment.

Animals↗
PubMedDate not supplied

T cell independent induction of antigen specific suppression of the antibody response.

Immune spleen cells (from mice given 2 x 10(7) HRBC 14 days earlier) when mixed in vitro with carrier-primed syngeneic spleen cells (from mice given 2 x 10(5) HRBC 3 days earlier) are able to suppress the anti-TNP and anti-HRBC PFC response to TNP-HRBC. If immune thymocytes are substituted for spleen cells suppression is not observed. This suppression is antigen specific, resistant to anti-T treatment or x-irradiation, and is exerted by nylon wool-retained cells of the immune spleen cell population. An antigen specific suppressive factor is released from immune spleen cells in culture. Under these experimental conditions, suppression appears to be mediated by a specific product of B rather than T cells present in the immune spleen cell population.

Animals↗
PubMedDate not supplied

Electron microscopic observations on T and B lymphocytes from spleens of syngeneic radiation chimaeras.

The ultrastructure of T and B lymphocytes has been examined in long-term syngeneic chimaeras and age-control mice. Spleen cell suspensions from these mice were passed through glass wool columns to obtain pure lymphocyte populations. These cells were then separated into T and B lymphocytes by nylon wool columns, and their purity was tested by cytotoxicity assays with anti-phi serum. Electron microscopic observations on such separated T and B lymphocytes did not reveal morphological differences except when the cells were fully differentiated, either as mature (T2) cells or plasmacells. In particular, T2 cells showed a very high cytoplasmic density, attributable to the presence of a larger number of microfilaments with respect to immature (T1) cells. In long-term chimaeras a significantly larger number of T2 cells was found as compared to age-control mice, and this morphological observation is correlated with the differences in immune reactivity and leukemia incidence previously described in these mice.

Age Factors↗