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G Tambussi

Publications and source records attributed to G Tambussi.

At least 55 records · Page 3Linked to original sources
PubMed1989

Monoclonal antibodies which react with the T cell receptor gamma/delta recognize different subsets of CD3+WT31- T lymphocytes.

A polyclonal CD3+4-8-WT31- cell line (termed SFG) was utilized for mice immunization in order to produce monoclonal antibodies (mAb) specific for the T cell receptor (TcR) gamma/delta. Hybrid supernatants were screened for their ability to induce SFG cells (but not conventional TcR alpha/beta + CTL lines) to kill the murine Fc receptor-positive P815 target cell line. Three hybrids, termed G1, A13 and F11, were isolated according to this screening. By indirect immunofluorescence G1 mAb reacted with 65% of SFG cells, while A13 stained 26% and F11 75% of cells. Double-fluorescence analysis revealed that G1 and A13 mAb identify two distinct, non-overlapping subsets of cells present in the SFG cell line. The reactivity of the mAb was also analyzed on a panel of representative TcR gamma/delta clones. G1 mAb reacted with 5 clones, that were also stained by the previously described BB3 mAb (recognizing the disulfide-linked form of TcR gamma/delta). These clones failed to react with A13 and delta-TCS-1 mAb (the latter of which is known to react with a non-disulfide-linked form of TcR gamma/delta). Out of six clones that reacted with A13 mAb, four were also delta-TCS-1+, whereas two were delta-TCS-1- and none of them reacted with G1, (or BB3) mAb. In contrast to the mAb above, F11 brightly stained the G1+A13- clones and more weakly the G1-A13+ clones. Moreover, F11 efficiently triggered both types of clones to kill the P815 target cells while G1 and A13 were able to trigger only G1+ or A13+ clones, respectively. None of the mAb above reacted with a large number of CD3+WT31+ clones. Antibody-induced surface antigen modulation experiments indicated that molecules recognized by G1, A13 and F11 were physically associated on cell surface with CD3 determinants. In addition, immunoprecipitation followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis (performed on 125I-surface-labeled TcR gamma/delta+ clones) revealed that molecules recognized by G1, A13 and F11 displayed an apparent mol. wt. corresponding to that of CD3-associated TcR molecules, immunoprecipitated by anti-CD3 mAb from the same clones.

Animals↗
PubMed1989

Human thymocytes expressing gamma/delta T-cell receptors.

Expression of T-cell receptors of gamma/delta type characterizes a small subset of peripheral T lymphocytes which is homogeneously composed of cytolytic cells and, in most instances, lack CD4 and CD8 differentiation antigens. By the use of anti-TCR gamma/delta MAbs it is possible to identify two distinct subsets of TCR gamma/delta+ cells that are characterized by a C gamma 1 or C gamma 2-encoded forms of gamma-chain, respectively. While the BB3 MAb-reactive (C gamma 1 encoded) cell subset is prevalent in peripheral blood (PB), these cells represent less than 10% in TCR gamma/delta+ thymocyte populations. In thymus, the majority of cells was found to react with delta-TCSI (or A13) MAbs. Culture of CD4-8- thymocytes (highly enriched in TCR gamma/delta+ cells) in IL-2 resulted in the de novo expression of CD8 surface antigen and of non MHC-restricted cytolytic activity. Cloning of CD4-8- thymocytes resulted, for the most part, in CD3+ TCR gamma/delta+ cells. Moreover, the majority of clones expressed the unusual delta-TCSI+ CD8+ phenotype and lysed the NK-sensitive K562 target cells. Analysis of the immunoprecipitated TCR molecules showed the existence of the (rare) heavy (55 kDa) form of gamma-chain. A redirected killing assay using murine P815 target cells and appropriate "stimulatory" antibodies was further employed for functional analysis of thymus-derived TCR gamma/delta+ clones. While anti-CD3 MAbs efficiently triggered the cytolytic activity of all clones irrespective of their phenotype, MAbs directed to TCR gamma/delta induced efficient lysis only of BB3+ or delta-TCSI+CD8 clones, but not of delta-TCSI+ CD8+ clones.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Differentiation, T-Lymphocyte↗
PubMed1989

Surface molecules involved in CD3-negative NK cell function. A novel molecule which regulates the activation of a subset of human NK cells.

Natural killer cells are characterized by the lack of CD3/TCR molecules and by the expression of CD16 and CD56 (NKHI or Leu19) surface antigens. In addition to their ability to lyse certain tumor target cells, they release lymphokines including tumor necrosis factor and interferon gamma. Another unexpected functional capability of at least some NK cells is the ability to specifically recognize and lyse certain normal allogeneic cells (PHA-induced blasts). MAbs directed to CD2 or to CD16 surface molecules induced triggering of NK cells leading to target cell (p815) lysis in a redirected killing assay. Importantly, different from induction of T cell activation, single anti-CD2 MAbs were sufficient to trigger NK cell function. Another MAb (GL183) inducing NK cell triggering recognized a novel surface molecules expressed on 20-50% of resting or cultured NK cells. Cloned GL183+ cells displayed a variable degree of cytolytic activity against a number of human target cells of different histotype; moreover, this activity was strongly enhanced by the addition of GL183 MAb. On the other hand, GL183 MAb inhibited lysis of murine lines (including P815). Thus on P815 target cells GL183 MAb has an effect antithetical to that of other stimuli including PHA, anti-CD2 or anti-CD16 MAbs. GL183 MAb, added simultaneously to one or another of the stimuli above, strongly inhibited the target cell lysis induced by these stimuli. Thus, GL183 may represent an important molecule in the process of activation/regulation of phenotypically-defined NK cell subsets.

Antibodies, Monoclonal↗
PubMed1989

Human T lymphocytes expressing gamma/delta T cell antigen receptor.

The majority of mature T lymphocytes express CD3-associated antigen receptor molecules (TCR) formed by alpha and beta chains. Recently, a minor subset has been identified that expresses a different CD3-associated heterodimer composed of gamma and delta chains. The TCR gamma/delta+ cell subset differs from conventional T cells for a number of phenotypic and functional characteristics. The simultaneous lack of both CD4 and CD8 antigens allows to greatly enrich TCR gamma/delta+ cells (by monoclonal antibodies and complement). Cloning of CD4-8- peripheral blood lymphocytes, under limiting dilution conditions, revealed that they are homogeneously composed of cytolytic cells which, in most instances, lyse tumor target cells. The formal proof has been provided that TCR gamma/delta+ cells are able to recognize antigens. Indeed they 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. The use of different monoclonal antibodies specific for TCR gamma/delta molecules allowed to identify two distinct subsets which bound BB3 and delta-TCS-1 mAbs, respectively. The BB3-reactive TCR molecules were represented by C gamma 1-encoded disulfide-linked heterodimers, whereas delta-TCS-1 reacted with C gamma 2-encoded nondisulfide-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 Ca2+ and lymphokine production or cytolytic activity). Analysis of the unfrequent delta-TCS-1+ clones which express surface CD8 molecules revealed that the "heavy" 55 kDa form of (C gamma 2-encoded) gamma chain is selectively expressed by this cell type. Analysis of the distribution of subsets expressing different TCR gamma/delta isotypes showed that the C gamma 1-encoded, BB3-reactive form is prevalent in the peripheral blood, but virtually absent in the thymus. In contrast, cells expressing the C gamma 2-encoded, delta-TCS-1 reactive form are relatively unfrequent in peripheral blood, but represent the majority of TCR gamma/delta+ thymocytes. In addition, upon culture in rIL-2, approximately half of the delta-TCS-1+ thymocytes expressed CD8 antigen, thus providing further evidence that major differences exist in the distribution of TCR gamma/delta+ subsets in thymus and in peripheral blood.

Antibodies, Monoclonal↗
PubMed1989

Human T cells expressing the gamma/delta T-cell receptor (TcR-1): C gamma 1- and C gamma 2-encoded forms of the receptor correlate with distinctive morphology, cytoskeletal organization, and growth characteristics.

BB3 and delta-TCS1 monoclonal antibodies identify two distinct nonoverlapping populations of T-cell receptor (TcR) gamma/delta (TcR-1)-positive cells, which express a disulfide-linked and a nondisulfide-linked form of TcR, respectively. BB3+ cells represented the majority of circulating TcR-1+ cells, but they were virtually undetectable in the thymus. On the other hand, delta-TCS1+ cells were largely predominant among TcR-1+ thymocytes but represented a minority in peripheral blood (PB). Similar distributions were observed by clonal analysis of thymocytes or PB TcR-1+ populations. The use of joining region (J)-specific probes indicated that BB3+ and delta-TCS1+ clones displayed different patterns of J rearrangement. Thus, the disulfide-linked form of TcR-1 (BB3+ clones) was associated with the expression of J segments upstream to the C gamma 1 gene segment, whereas the nondisulfide-linked form (delta-TCS1+ clones) was associated with the expression of J segments upstream to C gamma 2. delta-TCS1+ clones, in most instances, exhibited a growth pattern different from that of BB3+ or conventional TcR alpha/beta+ clones as they adhered promptly to surfaces, spread, and emitted long filopodia ending with adhesion plaques. Ultrastructural analyses showed, exclusively in delta-TCS1+ cells, nuclear deformations, uropod formation, and abundant cytoskeletal structures. In addition, immunofluorescence studies of this subset of TcR-1+ cells revealed the presence of abundant microtubules, intermediate filaments, and submembranous microfilaments. Thus, our findings suggest that delta-TCS1+ cells are capable of active motility.

Blotting, Southern↗
PubMed1989

Surface molecules involved in the activation and regulation of T or natural killer lymphocytes in humans.

The surface molecules that mediate activation of different subsets of T or NK cells have been reviewed. A suitable approach to the study of different lymphocyte activation pathways is provided by mAbs specific for these molecules. MAbs directed to the CD3 surface molecules mediate a polyclonal T-cell activation, whereas mAbs to "clonotypic" structures of TCR only trigger cells bearing the corresponding clonotypic determinant (thus mimicking the effect of antigen/MHC). MAbs directed to appropriate epitopes of CD2 molecules or to CD28 molecules mediate polyclonal T-cell activation, leading to triggering of the functional program of the cell (i.e. proliferation, lymphokine production or activation of the cytolytic machinery). Interaction of specific mAbs with CD3/TCR molecules leads to surface modulation of these molecules which lasts for 48-72 h. During this interval the cell is refractory to any further activation stimulus. No such refractoriness occurs following mAb-induced modulation of CD2 or CD28 surface molecules. The mechanisms by which CD3/TCR modulation results in the inactivation of T-cell function appears to involve the early metabolic steps of T-cell activation, as neither Ca++ mobilization nor IP3 formation could be further induced by any stimulus. The surface molecules and mechanisms involved in the activation of TCR gamma/delta cells are similar to those of TCR alpha/beta + cells. TCR gamma/delta molecules are heterogeneous in size and charge mobility. MAbs directed to one or another form of TCR gamma/delta trigger the functional program of the cell (primarily cytolytic function). However, a receptor form composed of a heavy form (55 kD) of the gamma chain appears to be relatively inefficient in signal transduction upon binding with anti-TCR mAbs. Evidence has also been provided that TCR gamma/delta + cells are capable of (allo)antigen responses and that polymorphic determinants of class I can be recognized (specific lysis of P815 cells transfected with HLA-A24 allele). Although the mechanisms and the surface receptor molecules involved in (CD3-, CD16+) NK cell activation are still poorly understood, several surface molecules have been identified that mediate NK-cell triggering. These include CD2 and CD16 and the novel GL183 molecule which is selectively expressed by a fraction of NK cells and thus identifies a well-defined NK subsets. Under appropriate conditions, mAbs to CD16 or GL183 mediate an inhibitory effect on the NK cell activation. These data suggest that also NK cells are characterized by surface molecules capable of initiating distinct pathways of cell activation and that, similarly to T lymphocytes, mechanisms exist which regulate NK cell function.

Antibodies, Monoclonal↗
PubMed1988

Human peripheral blood lymphocytes bearing T cell receptor gamma/delta. Expression of CD8 differentiation antigen correlates with the expression of the 55-kD, C gamma 2-encoded gamma chain.

We analyzed the CD3-associated molecules present on peripheral blood-derived TCR-gamma/delta+ clones that express CD8 surface antigens. Clones were derived by limiting dilution from CD3+WT31- FACS-purified populations derived from several donors. Eight of greater than 300 TCR-gamma/delta+ clones analyzed expressed CD8 and reacted with delta-TCS-1 mAb. Cell numbers suitable for more detailed analyses could be obtained from four clones, including one derived from thymus. Analysis of CD3-associated TCR molecules immunoprecipitated by anti-Leu-4 (anti-CD3) mAb under conditions that preserve the CD3/TCR association (1% digitonin) showed a predominant 55-60-kD molecule both under reducing and nonreducing conditions. On the other hand, the delta-TCS-1-reactive molecules immunoprecipitated from 25 CD3+ delta-TCS-1+ CD8- clones, in all instances, displayed a 40-44-kD mol mass. In two-dimensional PAGE, TCR-gamma molecules precipitated from delta-TCS-1+ CD8+ clones appeared more acidic than those of BB3+ or delta-TCS-1+ CD8+ clones. Southern analysis confirmed that this type of non-disulphide-linked TCR-gamma/delta is also coded for by the C gamma 2 gene segment.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1988

Two subsets of human T lymphocytes expressing gamma/delta antigen receptor are identifiable by monoclonal antibodies directed to two distinct molecular forms of the receptor.

Two mAbs directed to the TCR-gamma/delta were analyzed for their pattern of reactivity with CD3+WT31- cell populations or clones. In normal individuals, the BB3 mAb reacted with approximately 2/3 of peripheral blood CD3+WT31- lymphocytes, whereas delta-TCS-1 stained approximately 1/3 of such cells. In addition, the sum of the percentages of BB3+ and delta-TCS-1+ cells approximated the percentages of peripheral blood CD3+WT31- lymphocytes in seven normal donors tested. Also, in peripheral blood-derived polyclonal CD3+WT31- populations, cultured in IL-2, cells reacting with one or another mAb accounted for the whole cell population. On the other hand, only delta-TCS-1-reactive cells, but not BB3+ cells, could be detected in unfractionated as well as in CD4-8-thymocyte populations. Analysis of peripheral blood-derived CD3+WT31- clones showed that 70% of 72 clones analyzed reacted with BB3 mAb, but not with delta-TCS-1 mAb. On the other hand, delta-TCS-1 mAb stained the remaining BB3- clones. Five clones expressing medium-low amounts of CD8 antigen were BB3- delta-TCS-1+. Both types of clones lysed the Fc gamma receptor-bearing P815 target cell in the presence of anti-CD3 mAb (but not of mAb directed against HLA-DR, CD7 molecules, or TCR-alpha/beta). In this cytolytic assay, BB3 mAb induced target cell lysis only by BB3+ clones, whereas delta-TCS-1 mAb was effective only with delta-TCS-1+ clones. The CD3-associated surface molecules expressed by BB3+ or delta-TCS-1+ clones were analyzed after cell surface iodination and immunoprecipitation with the corresponding anti-TCR mAb or with anti-CD3 mAb (in digitonin-containing buffer). In SDS-PAGE, molecules immunoprecipitated from 13 BB3+ clones displayed, under nonreducing conditions, a molecular weight of 80 kD (in some cases, a minor 38-kD band could be detected). Under reducing conditions, two major components of 44 and 41 kD (and a minor component of 38 kD) were detected. On the other hand, TCR molecules immunoprecipitated from 11 different delta-TCS-1+ clones appeared as a diffuse band of 41-44 kD, both under reducing and nonreducing conditions (under non-reducing condition, an additional 38-kD band was present). Therefore, BB3+ cells express a disulphide-linked form of TCR-gamma/delta whereas delta-TCS-1+ cells express a non-disulphide-linked form.(ABSTRACT TRUNCATED AT 400 WORDS)

Antibodies, Monoclonal↗
PubMed1988

A monoclonal antibody specific for a common determinant of the human T cell receptor gamma/delta directly activates CD3+WT31- lymphocytes to express their functional program(s).

In an attempt to select mAbs specific for human TCR-gamma/delta, a polyclonal CD3+ 4-8-WT31- (TCR-gamma/delta+) cell line (MV1) was used for mice immunization. An mAb, termed BB3, reacted with MV1 cells but not with a large panel of CD3+ WT31+ (TCR-alpha/beta+) cell populations or clones. In addition, BB3 mAb reacted with the majority of CD3+ WT31- clones derived from six different donors. Double-color fluorescence experiments and FACS analysis showed that BB3+ cells were restricted to the CD3+ fraction of peripheral blood lymphocytes; in addition, in several donors the percentages (0.5-8% of total PBL) of BB3+ cells paralleled those of CD3+ WT31- cells. Surface molecules recognized by BB3 were susceptible to antibody-induced modulation; in addition, cell treatment with either BB3 or anti-CD3 mAb caused the simultaneous downregulation of the two molecules. That BB3 molecules are physically linked to CD3 antigen was further supported by immunoprecipitation experiments. Thus, under conditions that preserve the TCR-CD3 association, both BB3 and anti-CD3 mAb precipitated from 125I-labeled MV1 cells the same set of molecules. These consisted in the 18-28-kD CD3 molecules and in three bands of approximately 44, 42, and 38 kD under reducing conditions. When cell lysis was performed in 1% NP-40, the molecules immunoprecipitated by BB3 mAb were represented by an 80-kD band under nonreducing conditions, which resolved, under reducing conditions, in the three 44-, 42-, and 38-kD bands. Similar disulphide-linked forms of the TCR molecules were revealed in all of the other eight CD3+ WT31- BB3+ clones analyzed. Analysis of TCR molecules by electrophoresis (NEPHGE) showed that BB3 or anti-CD3 precipitated a 44-kD molecule displaying a basic PI (approximately 7.5) and two more acidic proteins (PI approximately 6) with a mol mass of 42 and 38 kD. Studies aimed to define whether stimuli directly acting on TCR-gamma/delta could induce CD3+ WT31- cell activation revealed that (a) In the presence of PMA, soluble BB3 mAb induced IL-2 production by MV1 cell line and by three other CD3+ WT31- BB3+ clones analyzed. (b) BB3 mAb-producing hybridoma used as triggering target, was efficiently lysed by CD3+ WT31- BB3+ effector cells (but not by CD3+ WT31+ BB3- conventional CTL). (c) Soluble BB3 mAb induced CD3+ WT31- BB3+ effector cells to lyse the Fc receptor-positive P815 target cells. (d) BB3-TCR-gamma/delta interaction on CD3+ WT31- BB3+ cells induced a rapid increase of [Ca2+]i levels, similar to that observed in response to anti-CD3 mAbs.

Animals↗
PubMed1988

Human cytolytic cell clones lacking surface expression of T cell receptor alpha/beta or gamma/delta. Evidence that surface structures other than CD3 or CD2 molecules are required for signal transduction.

We have analyzed the transmembrane signaling operating in human cytolytic lymphocytes lacking surface expression of the CD3/TCR complex. Peripheral blood lymphocytes were fractionated into CD3+ and CD3- on the FACS and cloned under limiting conditions in the presence of PHA and IL-2. Approximately 90% CD3+ and 10% CD3- cells underwent clonal expansion. Clones obtained from the CD3- fraction belonged to two main phenotypic groups: CD2+ CD7+ and CD2- CD7+. Several clones were expanded and analyzed for surface phenotype and function. All of the five clones selected for detailed analysis did not express CD4, CD8, and CD28 antigens and did not release IL-2, whereas they displayed cytolytic activity against NK-sensitive, NK-resistant, and fresh tumor target cells. After stimulation with anti-CD2 mAbs or PHA a rapid increase in [Ca2+]i was detected in CD3- CD2+ CD7+ clones. This increment was caused by the release of Ca2+ from intracellular stores and by the influx from the extracellular compartment. Signaling in response to PHA did not appear to be dependent upon surface expression of CD2 molecules since antibody-induced modulation of CD2 did not prevent PHA-induced signal transduction. Similarly, in CD3- CD2- CD7+ clones [Ca2+]i increments and inositol phosphate formation occurred after stimulation with PHA. These data indicate that the functional PHA-binding structures, expressed in both groups of CD3- clones, are distinct from CD3/TCR complex and CD2 molecules.

Antibodies, Monoclonal↗
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↗
PubMed1988

Stimulation and proliferation of CD4+ peripheral blood T lymphocytes induced by an anti-CD4 monoclonal antibody.

There is experimental evidence that the CD4 molecule participates in the antigen-driven activation of T cells expressing this surface glycoprotein. Whether CD4, a member of the immunoglobulin supergene family, acts as a ligand-binding molecule and/or is directly involved in the activation pathway has yet to be established. In this study, we show that human CD4+ lymphocytes can be activated by exposure to the anti-CD4 monoclonal antibody (mAb) B66. Normal peripheral blood CD4+ cells were induced to proliferate and to synthesize interleukin 2 (IL 2) by the antibody. The specificity of the antibody stimulatory activity was tested by using IL 2-producing clones bearing either CD4 or CD8 on their surface. IL 2 production was induced by mAb B66 in CD4+, but not CD8+, clones, whereas both types of clones responded to stimulation by the anti-CD3 mAb Leu-4. Despite its unique stimulatory activity, mAb B66 shared with other anti-CD4 antibodies the ability to inhibit the specific cytolytic activity of CD4+ effector cells. These results clearly indicate that cross-linking of surface CD4 molecules with appropriate antibodies can fully activate CD4+ lymphocytes. Whether the natural ligand for CD4 can trigger this activation pathway remains to be defined.

Antibodies, Monoclonal↗
PubMed1988

T-lymphocyte subsets and delayed type hypersensitivity as classification parameters for HIV infection among drug-addicts.

HIV selectively infects T helper lymphocytes, which play an essential role in cell-mediated immunity mechanisms. Impairment of these mechanisms can be evaluated, other than by clinical parameters, by testing lymphocytic subsets and cutaneous delayed type hypersensitivity. All these indices are used in the Walter Reed Foundation (WR) staging system, which includes the different stages of HIV infection. In our study we investigated the above mentioned parameters in a series of 180 HIV positive PDAs. A classification of the same patients according to WR's criteria was also designed. Of our patients, 46.1% resulted normoergic, 27.2% hypoergic and 26.7% anergic. Of all normoergic subjects, 83.7% (with more than 400 OKT4+ cells/mmc) could be assigned to the WR2 and 16.3% (with less than 400 OKT4+ cells/mmc) to the WR3 staging group. Among the hypoergic patients, only 34.7% were assignable to the WR4 group, whereas the majority (65.3%) had more than 400 OKT4+ cell/mmc. Even among the anergic group, 62.5% did not fit the WR5 stage, exhibiting an OKT4+ level higher than 400/mmc. In the latter 2 groups (referred to as D and E), T helper lymphocyte counts were performed at regular intervals; however, only the ones followed-up for at least 6 months were evaluated. OKT4+ cells were shown to decrease more frequently and more rapidly in the anergic than in the hypoergic patients, which points to cutaneous anergy as representing an early sign of impairment of cell-mediated immunity.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Partial inefficiency of T cell receptors gamma/delta composed of a heavy (55-kD) gamma chain to mediate cell activation upon binding to specific monoclonal antibodies.

We analyzed CD8+ T cell receptor (TCR) gamma/delta+ (delta-TCS-1 reactive) cell clones expressing the 55-kD gamma chain for their susceptibility to triggering by monoclonal antibodies (mAbs) specific for TCR or CD3 molecules. Clones were derived by limiting dilution from CD3+, WT31- FACS-purified peripheral blood populations or CD4-CD8- thymocytes (a fraction of the latter cells expressing de novo CD8 surface antigen upon culture in IL-2). Clones were screened according to their reactivity with both anti-CD8 and delta-TCS-1 mAbs. Analysis of CD3-associated molecules immunoprecipitated by anti-Leu-4 (anti-CD3) mAb under conditions which preserve the CD3/TCR association (1% digitonin) showed a predominant 55-60-kD molecule both under reducing and non-reducing conditions. All clones expressing the delta-TCS-1+ CD8+ surface phenotype derived from either thymus or peripheral blood lysed the Fc gamma receptor-bearing P815 target cells in the presence of anti-CD3 mAb. On the other hand, delta-TCS-1 mAb was poorly efficient in triggering the lytic machinery of these clones, while it induced target cell lysis by delta-TCS-1+ CD8- clones.

Animals↗
PubMedDate not supplied

Evaluation of Subcutaneous Proleukin (interleukin-2) in a Randomized International Trial (ESPRIT): geographical and gender differences in the baseline characteristics of participants.

BACKGROUND: ESPRIT, is a phase III, open-label, randomized, international clinical trial evaluating the effects of subcutaneous recombinant interleukin-2 (rIL-2) plus antiretroviral therapy (ART) versus ART alone on HIV-disease progression and death in HIV-1-infected individuals with CD4+ T-cells > or =300 cells/microL. OBJECTIVES: To describe the baseline characteristics of participants randomized to ESPRIT overall and by geographic location. METHOD: Baseline characteristics of randomized participants were summarized by region. RESULTS: 4,150 patients were enrolled in ESPRIT from 254 sites in 25 countries. 41%, 27%, 16%, 11%, and 5% were enrolled in Europe, North America, South America, Asia, and Australia, respectively. The median age was 40 years, 81% were men, and 76%, 11%, and 9% were Caucasian, Asian, and African American or African, respectively. 44% of women enrolled (n = 769) were enrolled in Thailand and Argentina. Overall, 55% and 38% of the cohort acquired HIV through male homosexual and heterosexual contact, respectively. 25% had a prior history of AIDS-defining illness; Pneumocystis jirovecii pneumonia, M. tuberculosis, and esophageal candida were most commonly reported. Median nadir and baseline CD4+ T-cell counts were 199 and 458 cells/muL, respectively. 6% and 13% were hepatitis B or C virus coinfected, respectively. Median duration of antiretroviral therapy (ART) was 4.2 years; the longest median duration was in Australia (5.2 years) and the shortest was in Asia (2.3 years). 17%, 13%, and 69% of participants began ART before 1995, between 1996 and 1997, and from 1998 onward, respectively. 86% used ART from two or more ART classes, with 49% using a protease inhibitor-based regimen and 46% using a nonnucleoside reverse transcriptase inhibitor-based regimen. 78% had plasma HIV RNA below detection (<500 cp/mL). CONCLUSION: ESPRIT has enrolled a diverse population of HIV-infected individuals including large populations of women and patients of African-American/African and Asian ethnicity often underrepresented in HIV research. As a consequence, the results of the study may have wide global applicability.

Adult↗
PubMedDate not supplied

The rationale for a study on HIV-1 reverse transcriptase mutations and outcome of antiretroviral therapy with two nucleoside analogs.

The development of resistance to antiretroviral drugs has been recognized as an important cause of treatment failure in HIV-1-infected patients; however the correlation between emergence of resistance and treatment failure has not been yet clearly defined. The high rate of viral replication, together with the lack of proof reading activity of HIV-1 reverse transcriptase, accounts for the rapid establishment of extensive genotypic variation, resulting in the emergence of viral mutants showing primary or secondary resistance to antiretroviral drugs. In this regard, phenotyping and genotyping allow the detection of drug resistance. Both tests have advantages and limitations compared to each other. The complete suppression of viral replication seems to be the best way to avoid occurrence of drug resistance, and viral loads below the limit of detection can be usually achieved by a combination of 3 antiretroviral drugs. In this scenario, the proportion of HIV-1-infected patients on dual therapy is still relevant in Italy. We believe that the study of this subset of individuals is very important, as resistance to nucleoside analogues may impair the outcome of a future triple therapy. In addition, this study could contribute to define the role of resistance assays in the management of HIV-1-infected patients.

Anti-HIV Agents↗