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E Ciccone

Publications and source records attributed to E Ciccone.

84 records · Page 5Linked to original sources
PubMed1988

Antigen recognition by human T cell receptor gamma-positive lymphocytes. Specific lysis of allogeneic cells after activation in mixed lymphocyte culture.

These experiments were designed to define the ability of human TCR-gamma+ cells to recognize allogeneic cells. TCR-gamma+-enriched populations were obtained by treating peripheral blood E-rosetting cells with anti-CD4 and anti-CD8 mAbs. The resulting populations were CD2+4-8- expressed variable proportions of CD3+ cells (40-90%), and did not react with the WT31 mAb, which is specific for a framework determinant of the alpha/beta heterodimer that serves as receptor for antigen on most human T lymphocytes. After mixed lymphocyte culture with irradiated allogeneic cells for 7 d and 3 additional days in rIL-2 (100 U/ml), cells underwent proliferation in three of five individuals tested. In addition, MLC-derived cells lysed 51Cr-labeled PHA-induced blasts derived from the allogeneic cells used as stimulator, but not allogeneic unrelated or autologous blast cells. No cytotoxicity against autologous or allogeneic target cells could be induced by culturing CD3+4-8-WT31- lymphocytes in MLC with irradiated autologous cells. Surface iodination of allogeneic MLC-activated CD3+4-8-WT31- cells followed by lysis in 1% digitonin and immunoprecipitation with anti-CD3 mAb indicated that the CD3-associated molecules consisted of a major 45-kD band and a minor band of 43 kD. Northern blot analysis showed that mRNA for the gamma chain was expressed at high levels, whereas mRNAs for alpha and beta chains were missing. These data support the notion that TCR-gamma rather than TCR-alpha/beta is expressed in allospecific CD3-4-8-WT31- cell populations. Clones were further derived from MLC-stimulated CD3+4-8-WT31- populations. All the seven clones studied in detail maintained the surface phenotype as well as the cytolytic pattern of the original MLC populations, thus only specific allogeneic PHA-induced blasts were lysed. NK-sensitive as well as NK-resistant tumor targets were variably susceptible to lysis; therefore, specific cytolytic activity against allogeneic cells was not necessarily linked to the expression of MHC-nonrestricted cytotoxicity against tumor cells.

Clone Cells↗
PubMed1987

CD3+ WT31- peripheral T lymphocytes lack T44 (CD28), a surface molecule involved in activation of T cells bearing the alpha/beta heterodimer.

We have applied two-color fluorescence cytofluorometric techniques to the analysis of the distribution of T44 and CD3 antigens in peripheral blood human lymphocytes. While most CD3+ cells co-expressed T44 antigen, a small distinct subset was CD3+ T44- (2-10% of CD3+ cells). This cell subset also did not react with the WT31 monoclonal antibody (mAb), specific for an alpha/beta framework determinant of the T cell receptor (TCR). Lack of T44 antigen expression was also observed in purified CD3+ WT31- polyclonal populations that had been cultured in medium containing interleukin 2 (IL2) and as well as greater than 30 clones expressing the CD3+4-8-WT31- surface phenotype. Immunoprecipitation experiments confirmed that expression of T44 molecules was confined to CD3+ WT31+ peripheral blood T cells. While conventional CD3+ WT31+ cells produced IL2 in response to mAb directed to CD2, CD3 or T44 surface molecules, CD3+ WT31- cells did not respond to anti-T44 mAb but released IL2 following stimulation with anti-CD2 or anti-CD3 mAb. Therefore, assuming that anti-T44 mimicks the effect of a still undefined natural ligand our data suggest that T cells expressing the gamma-gene surface product may be signalled by stimuli which differ, at least in part, from those acting on CD3+ WT31+ T lymphocytes.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1987

Human CD3+4-8-WT31- T lymphocyte populations expressing the putative T cell receptor gamma-gene product. A limiting dilution and clonal analysis.

The small peripheral blood CD3+ T cell population lacking both CD4 and CD8 surface antigens has been analyzed in the present study. Enriched CD3+4-8- populations were obtained by depletion with anti-CD4 or anti-CD8 monoclonal antibodies (mAb) and complement. The resulting populations contained greater than 99% CD2+ cells, whereas CD3+ represented approximately 50%. Virtually all of the cells were CD4-8- and did not react with the WT31 mAb, specific for a framework determinant of the alpha/beta T cell receptor (TCR). In order to analyze the molecular nature of CD3-associated molecules in CD3+WT31- populations, cells were stimulated with 0.5% phytohemagglutinin (PHA) for 24 h and expanded for an additional 7-14 days in interleukin 2 (IL 2). The resulting cells were greater than 95% CD3+ and expressed neither CD4/CD8 nor WT31 antigen. Cell surface iodination followed by cross-linking and immunoprecipitation with anti-CD3 mAb showed that CD3-associated molecules consisted of a major 45-kDa band and a minor band of 43 kDa. Thus, whereas CD3-associated molecules isolated from polyclonal CD3+WT31+ populations (expanded in IL 2 under the same culture conditions) appeared as diffuse bands, CD3-associated molecules isolated from CD3+WT31- populations displayed a homogeneous molecular mass. Northern blot analysis revealed the presence of mRNA for the TCR gamma chain whereas the mRNA for the alpha chain was mostly represented by a truncated (1.2 kb) form. Also small amounts of a nonproductive mRNA for the beta chain were detected. Freshly isolated CD3+WT31--enriched populations proliferated in response to PHA and concanavalin A, moreover, IL 2 was detected in the culture supernatants after cell stimulation. By applying culture conditions which allow virtually all T cells to undergo clonal expansion, approximately 1/3 CD3+WT31- were clonogenic. In addition, the large majority of proliferating microcultures lysed the K562 cell line and about half the natural killer (NK)-resistant fresh melanoma target cells. A large number of clones derived from CD3+WT31- enriched populations by limiting dilution has been further analyzed. More than 95% of the clones were CD3+4-8-WT31-; 12/15 clones analyzed in more detail displayed NK activity and 6/15 lysed melanoma cells; in addition, all lysed P815 target cells in the presence of PHA, thus indicating that all the clonogenic CD3+WT31- cells have a cytolytic potential.

Antibodies, Monoclonal↗
PubMed1987

Human lymphoblastoid cell lines secreting antibodies with restricted HLA specificity.

Peripheral B lymphocytes obtained from three healthy individuals who had been immunized against peripheral blood lymphocytes from appropriate HLA-incompatible donors were transformed by the use of Epstein-Barr virus. The transformed blastoid B cells were repeatedly subcultured by means of "cluster picking," and the HLA antibody-producing cultures were identified by testing the culture supernatants by means of the cytotoxicity assay, using the corresponding donor cells. Thus far, four cell lines that secrete cytotoxic HLA antibodies (MP1, 3, 4, and 5) have been established. Specific immunoabsorption experiments revealed that the antibody activity is carried by lambda-type IgM for MP1, by kappa-type IgM for MP3 and MP5, and by both for MP4. Specificity analysis of a panel of HLA-pretyped cells indicated that MP1 detects DQw2, whereas MP5 recognizes B7. The specificity of MP3 was similar to a DQ specificity termed DC5 (probably equivalent to TA10) but not the same. In the case of MP4, both of the lambda-type and kappa-type antibodies appeared to be directed toward new HLA class II determinants.

Antibody Specificity↗
PubMedDate not supplied

Analysis of CD3-associated molecules in CD4- 8- human T cell clones lacking the typical alpha/beta T cell receptor.

Four clones were isolated from CD3+ 4- 8- normal peripheral blood T lymphocytes. They lacked expression of the typical alpha/beta T cell receptor, as assessed by reactivity with the WT31 monoclonal antibody (mAb) recognizing a non-polymorphic structure of the alpha/beta heterodimer. All the four clones lysed the natural killer-sensitive K562 target cells and released interleukin-2 following stimulation with phytohemagglutinin. After cell treatment with the cross-linking agent dithiobis-succinimidyl-propionate, molecules immunoprecipitated with an anti-CD3 mAb were represented by a major 45-kD and a minor 43-kD band. These molecules were different from typical alpha/beta molecules and are likely to represent the molecular product of the human gamma gene.

Antigens, Differentiation, T-Lymphocyte↗
PubMedDate not supplied

Anatomy of the immune system: facts and problems.

In the introductory section of this report, the anatomy of the immune system, from organs and tissues to molecules, will be reviewed briefly. Cell proliferation and differentiation in the central lymphoid organs (thymus and bone marrow) yield a repertoire of T- and B-cell clones that seed into peripheral lymphoid organs (spleen, lymph nodes and Mucosa-Associated Lymphoid Tissue, MALT), where humoral and cell-mediated antigen-specific immune responses occur. The stringent process of clonal selection in the central lymphoid organs implies deletion of inappropriate cells via apoptosis. In the peripheral lymphoid organs, the potential of unlimited activation and expansion of lymphocytes in response to antigens is primarily regulated by apoptosis and anergy. These events, on the one hand, are relevant to prevent autoimmunity and lymphoproliferative disorders; on the other hand, clonal deletion and anergy provide a detrimental escape to immune recognition of malignant cells. Two major inhibitory mechanisms of the immune response have emerged recently. One is linked to the existence of bona fide suppressor cells and cytokines; the other relies on the existence of inhibitory molecules expressed by T, B and NK cells, as well as by other leukocytes. In the studies herein reported, emphasis will be given to surface membrane molecules that down-regulate T-cell-mediated immune responses. These molecules control interactions between T cells and antigen presenting cells (APC's) or target (virus-infected or mutated) cells that have to be killed. Two sets of molecules exist that either upregulate (coactivation molecules) or down-regulate (inhibitory molecules) T-cell mediated responses. The latter aspect of the immune regulation, i.e. molecules that limit the expansion of T-cell clones following specific recognition of antigens will be considered in depth. Two inhibitory molecules, CD152 (CTLA-4) and CD85/LIR-1/ILT2 are expressed in all T cells, being largely confined within intracellular compartments of these lymphocytes when they are in a resting state, but ready to be shuttled to and from the plasma membrane when cells are activated following encounter with antigen. Membrane expression of the two inhibitory molecules is transient and is regulated by an internalization process directed to endosomal compartments and to receptor degradation and/or recycling. CTLA-4 and CD85/LIR-1/ILT2 play a pivotal role in T-cell homeostasis that follows any cell-mediated immune response; their localization and functional role will be thoroughly analyzed. In the last part of this study a major question will be faced, i.e. is the containment of the possibly unlimited expansion of the immune system due to a blockade of the cell cycle? Or, else, could be apoptosis the sole mechanism responsible? Experimental data in support of the latter contention will be provided.

Animals↗
PubMedDate not supplied

Phenotypic and functional characterization of human T lymphocytes expressing a gamma/delta T cell antigen receptor.

Most mature T lymphocytes express CD3-associated antigen receptor molecules (TCR) formed by alpha and beta chains. Recently, a minor subset has been identified that express a different CD3-associated TCR composed of gamma and delta chains. The cell subset expressing TCR gamma/delta differs from conventional T cells in a number of phenotypic and functional characteristics. The simultaneous lack of both CD4 and CD8 antigens at the cell surface allows one to greatly enrich for TCR gamma/delta + cells (by monoclonal antibodies, mAbs and complement). Cloning of CD4-8- peripheral blood lymphocytes revealed that they are homogeneously composed of cytolytic cells which, in most instances, lyse tumor target cells. TCR gamma/delta + cells proliferated in response to allogeneic cells in mixed lymphocyte culture (MLC) and MLC-derived TCR gamma/delta + cells specifically lysed PHA-induced blast cells bearing the stimulating alloantigens, thus providing the formal proof that they recognize (allo)antigens. The use of different mAbs specific for TCR gamma/delta molecules allowed us to identify two distinct subsets which bound BB3 and delta-TCS-1 mAbs, respectively. The BB3-reactive molecules in peripheral blood-derived TCR gamma/delta + cells were represented by C gamma 1-encoded disulphide-linked heterodimers, whereas delta-TCS-1 reacted with C gamma 2-encoded non disulphide-linked molecules. Both BB3 and delta-TCS-1 mAb induced activation of cloned cells expressing the corresponding antigenic determinants (as assessed by measurements of intracellular Ca++ and/or lymphokine production or cytolytic activity).(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗