Biomedical subjects

F Gerosa

Publications and source records attributed to F Gerosa.

31 records · Page 2Linked to original sources

PubMed1988

Induction of poly(ADP-ribose) polymerase gene expression in lectin-stimulated human T lymphocytes is dependent on protein synthesis.

The poly(ADP-ribose) polymerase mRNA level in quiescent T lymphocytes was low, but was significantly higher than that in B lymphocytes or monocytes. When T lymphocytes were stimulated with phytohemagglutinin, a prompt increase in the mRNA level was observed from 4 hours after stimulation. The level of poly(ADP-ribose) polymerase mRNA reached a maximum in the late G1 phase about 1-2 days after lectin stimulation, and then decreased gradually returning to the basal level 10 days after lectin stimulation. Cycloheximide abrogated increase in poly(ADP-ribose) polymerase gene expression suggesting that a newly synthesized protein(s) was involved in poly(ADP-ribose) polymerase gene induction in lectin-stimulated T lymphocytes.

B-Lymphocytes↗

PubMed1988

Heterogeneity of lymphokine-activated killer (LAK) populations at the clonal level: both NK and CD3+, CD4-, CD8- clones efficiently mediate tumor cell killing.

To investigate at the clonal level the phenotypic and functional properties of interleukin 2 (IL-2) activated killer cells (LAK), recombinant IL-2 activated peripheral blood lymphocytes were cultured under limiting conditions. Among 56 clones that lysed P815 in the presence of phytohemagglutinin (PHA) (22% of total proliferating microcultures) 36 clones lysed also the natural killer (NK)-sensitive K562 and the NK-resistant Hu126 glioma cell lines and one clone lysed only the K562 cell line. Several LAK clones were further assayed for both phenotype and functional activity. Of 22 clones, 10 were CD3-, CD4-, CD8-, and expressed the CD16 marker of NK cells; only one clone had the conventional phenotype of cytolytic T cells (CD3+, CD4-, CD8+), while 11 clones were CD3+, CD4-, CD8- and did not express alpha/beta heterodimer of T-cell antigen receptor as identified by WT31 monoclonal antibody. Only one of the latter clones was CD16+. Endogenous production of IL-2 after stimulation with PHA and phorbol myristate acetate was positive in 3/9 CD3- and in 8/8 CD3+, CD4-, CD8- clones. CD3- mediated strong antibody-dependent cellular cytotoxicity, a function exerted also by some CD3+, CD4-, CD8- T-cell clones to a lower extent. CD3+, CD4-, CD8- T-cell clones lysed different major histocompatibility complex unrelated tumor targets; moreover, this lytic activity seems to be CD3 dependent.

Antibody-Dependent Cell Cytotoxicity↗

PubMed1986

Interleukin-2 production in response to phytohemagglutinin is not necessarily dependent upon the T3-mediated pathway of T-cell activation.

The present study was designed to investigate whether heterogeneity exists in the requirement for T3 molecules in the mechanism of T-cell activation and interleukin-2 (IL-2) release by IL-2-producing T-cell clones. Clones were derived from peripheral blood by a culture system which allows clonal expansion of essentially all T lymphocytes or from mixed lymphocyte culture (MLC) activated T-cell population. IL-2-producing clones were selected and cell aliquots treated with anti-T3 monoclonal antibodies (mAb) to induce modulation of T3 surface molecules. Although stimulation of modulated clones with different anti-T3 mAb did not lead to IL-2 production, 4/39 of these clones produced IL-2 after stimulation with phytohemagglutinin (PHA). The ability of these clones to be activated by PHA could not be explained by incomplete T3 modulation. In addition, two alloreactive clones were isolated from MLC population in which modulation of T3 antigens abrogated the IL-2 production induced by either anti-T2 mAb or allogeneic stimulation but had no effect on PHA-induced IL-2 release. These data further support the concept that PHA may trigger some T cells via surface molecules that are independent from the T3-Ti cell receptor molecular complex.

Antibodies, Monoclonal↗

PubMed1985

B cell growth factor activity of immunoaffinity-purified and recombinant human interleukin 2.

We investigated the effect of recombinant and affinity-purified human interleukin 2 (IL2) on human B cell proliferation. Five X 10(4) nonadherent spleen cells that had been depleted twice of T cells were activated by 3-day culture with formaldehyde-killed Staphylococcus aureus Cowan strain I (SAC) prior to addition of tested growth factors. Cultures were harvested 72 h later. It was found that both IL2 preparations led to optimal cell proliferation compared with a control supernatant obtained by 36 h phytohemagglutinin stimulation of spleen mononuclear cells. Moreover, the effect of such spleen supernatant on B cell proliferation correlated with the IL2 activity since its B cell growth factor activity (BCGF) was not greater than that of purified IL2 and no residual BCGF activity could be detected after absorption of all IL2 activity by the IL2-dependent cytotoxic T lymphocyte line cells. T cells, enumerated as E-rosetting cells as well as T3+ cells, represented 0.2 to 2% of the cells recovered at termination of the cultures (day 6) and there were less than 1% E-rosetting cells in freshly purified or SAC-activated (day 3) B cell populations. Therefore, we conclude that IL2 is a growth factor not only for activated T cells but also for activated human B cells.

B-Lymphocytes↗

PubMed1985

Phenotypic and functional heterogeneity of human T lymphocytes producing B-cell growth factor(s): a clonal analysis.

Human T cells active on B-cell proliferation are phenotypically and functionally heterogeneous. A series of 43 human T-cell clones, selected according to their ability to release factors active on B-cell proliferation, were analyzed. B-Cell proliferation was evaluated by two different assays, namely, a costimulation assay with anti-mu antibody or by an assay based on B-cell preactivation with Staphylococcus aureus. Eight of these clones expressed the T4-/T8+ phenotype while the remaining were T4+/T8-. The large majority had T-cell growth factor activity as well. However, some clones appeared to have B-cell growth factor activity only. Fourteen clones (eight T8+ and six T4+) also displayed cytolytic activity in a phytohemagglutinin-dependent cytolytic assay.

Antibodies, Anti-Idiotypic↗

PubMed1984

Frequent coexpression of cytolytic activity and lymphokine production among human T lymphocytes. Production of B cell growth factor and interleukin 2 by T8+ and T4+ cytolytic clones.

These studies were designed to determine the degree of overlapping between cytolytic function and lymphokine production among peripheral blood human T lymphocytes. T8+ and T4+ cells were obtained by sorting purified T cells using the fluorescence-activated cell sorter (FACS) and cloned at 0.25 cells/well in a microculture system that allows clonal growth of every T cell. 49/49 T8+ clones but only 5/102 T4+ clones displayed cytolytic activity, as assessed by a lectin-dependent assay. Cytolytic clones were further analyzed for their ability to release interleukin 2 (IL2) and B cell growth factor(s) (BCGF) upon 24 h stimulation with phytohemagglutinin. Fifteen percent and 18% of T8+ cytolytic clones were producing IL2 and BCGF, respectively; in addition 3 out of 5 T4+ cytolytic clones released both lymphokines. Although the majority of cytolytic clones producing IL2 were also producing BCGF, 5 clones released either BCGF or IL2. The present studies indicate that the coexpression of cytolytic and helper/inducer functions is relatively common among peripheral blood T lymphocytes, irrespective of their T8+ or T4+ phenotype.

B-Lymphocytes↗

PubMed1984

Specific IgE antibodies in twenty-eight workers with diisocyanate-induced bronchial asthma.

A specific IgE-mediated response was evaluated in twenty-eight workers exposed to TDI or MDI, with diagnosis of occupational asthma and positive to bronchial provocative challenge. The presence of anti-diisocyanate IgE was observed in 27% of subjects exposed to TDI and 83% of those exposed to MDI, particularly in individuals who experienced an acute massive exposure. An immediate-type response to bronchial provocative test was found in 66% of individuals with specific antibodies. Specific IgE are prevalent (91%) in subjects who developed symptoms before 6 years of exposure to isocyanates. The results suggest an association between the presence of specific IgE, early asthmatic symptoms and heavy episodic exposure.

Asthma↗

PubMed1982

Binding of sheep erythrocytes in chronic lymphocytic leukemias of B-cell origin.

Two patients with B chronic lymphocytic leukemia having leukemic cells that bind sheep red blood cells by different mechanisms are described. In the first case, rosette formation was mediated by the anti-sheep erythrocyte activity of a monoclonal surface IgMk, related to Forssman antigen. In the second, E-rosette formation was found to be independent of both surface immunoglobulins and the classic E-rosette receptor since the leukemic cells were recognized neither by the OKT-11 monoclonal antibody nor by other markers specific to T-cell lineage. Evaluation of these rare cases emphasizes that detection of surface immunoglobulins and spontaneous rosetting are not sufficient for the characterization of leukemic clones and raises some doubts concerning the use of available surface markers in the characterization of lymphoproliferative disorders.

Aged↗

PubMed1982

Immunocompetence and dietary protein intake in early infancy.

Forty-one normal full-term infants were fed from birth, during the first 4.5 months of life, different diets based on two formulas similar in rough composition but basically different, the one being constituted only of cow milk protein and the other of soy protein. From each of the two formulas two different dilutions were prepared so that all diets supplied about 100 kcal/kg/day, but, respectively, 2.0 and 4.0 g/kg/day of cow milk protein and 2.0 and 5.0 g/kg/day of soy protein. After 4.5 months, growth in weight, length, and head circumference was normal and very similar in all infants. Gammaglobulin, immunoglobulin, transferrin, and some complement fractions (particularly C'3, C'1 INA, C'3 PA) were lower in infants receiving soy protein diets than in those receiving cow milk protein diets, and, within each type of diet, in those infants receiving lower amounts of protein. In particular, values of infants receiving 5.0 g/kg/day of soy protein were roughly comparable to those of infants receiving 2.0 g/kg/day of cow milk protein. B lymphocyte markers and reactivity did not show significant differences among the various groups. T lymphocyte markers and reactivity showed an impairment in soy protein diets (and in particular in 2.0 g/kg/day protein diets) with respect to cow milk diets. It was also observed that morbidity (mainly infections of upper respiratory tract) was higher in those infants who took soybean protein and in those who took lesser amount of protein.

B-Lymphocytes↗

PubMedDate not supplied

Heterogeneity of B cell growth factor (BCGF)-producing T cells in humans. Clonal analysis of BCGF-producing cells within T4+ and T8+ subsets and evidence for the involvement of different growth factors in different BCGF assays.

Human peripheral blood T cells were cloned under conditions allowing the clonal expansion of virtually all T cells. Clones derived from T4+ or T4- (T8+) subsets were screened for their ability to induce B cell proliferation either in the Staphylococcus aureus Cowan-I (SAC)-driven assay or in the costimulation assay based on the use of anti-mu antibodies. BCGF activity in the SAC- and in the anti-mu-driven system was displayed by 13% and 15% T8+ clones, respectively, while 74% and 79% T4+ clones had BCGF activity in the same assay. SN of clones with BCGF activity were further screened for their susceptibility to the inhibition by CM 269 (anti-IL-2 receptor) monoclonal antibody. All clones were inhibited in the SAC assay, whereas several clones were partially or totally resistant to inhibition in the anti-mu assay. Nine of such non-inhibited clones were further analyzed for their ability to produce gamma-IFN (known to act as a BCGF) and IL-2: six of them were found to produce gamma-IFN, while none produced any detectable IL-2 activity.

Cells, Cultured↗

PubMedDate not supplied

Analysis of physical parameters of discrete cell populations. (Double data control by combining specific density and sedimentation velocity cell separation techniques).

Physical cell separations are employed in a number of investigations in cell biology, immunology, haematology, etc., when the study of homogeneous cell populations is required. Differences in physical characters are reflected in the various functions and differentiation stages of the individual cell lines, which can be concentrated and separated into discrete cell classes by these methods. The correct utilization of the separation techniques mainly depends on the knowledge of the physical laws on which they are based. This paper discusses the theoretical background and a practical application of a combined separation procedure which uses velocity sedimentation and linear density gradient and also gives a double check of the physical data obtained in the different experiments. As an example of this analysis, cells from the lymph nodes of Hodgkin's patients were separated, and the physical parameters as well as some sources of 'error' in the experimental results obtained with these 'Hodgkin's cells' are reported and discussed.

Cell Separation↗

PubMedDate not supplied

Structural analysis of the CD69 early activation antigen by two monoclonal antibodies directed to different epitopes.

The biochemical structure of CD69 early activation antigen has been characterized by means of two newly isolated mAb, namely C1.18 and E16.5. Upon analysis by SDS-PAGE, C1.18-reactive molecules immunoprecipitated from 125I-surface labeled PMA activated PBL consisted of a 32 + 32 kD dimer, a 32 + 26 kD dimer, a 26 + 26 kD dimer and a 21 + 21 kD dimer. E16.5-reactive molecules consisted of a 26 + 26 kD dimer and a 21 + 21 kD dimer. Cross absorption experiments showed that E16.5 mAb reacts with an epitope of the CD69 molecule distinct from the one recognized by C1.18 mAb and present only on a subpopulation of the CD69 molecular pool. The patterns of migration of C1.18- and E16.5-reactive molecules in two-dimensional gel-electrophoresis, under reducing conditions before and after treatment with Endoglycosidase F enzyme suggest that the two mAb recognize the same glycoprotein structure, but in two distinct glycosylation forms, both expressed on the cell surface membrane. Finally, p32, p26 and p21 of CD69 complex obtained from three distinct normal donors did not show appreciable structural polymorphism, by two-dimensional peptide mapping, not only among single subunits within the same individual, but also among homologous subunits in distinct individuals. Further, it was found that CD69 complex is expressed at the cell surface of resting PBL, although at a very reduced level in comparison to PMA activated cells. C1.18 and E16.5 mAb induced comparable cell proliferation and IL-2 production in PBL in the presence of PMA. C1.18 mAb increased intracellular free calcium concn in PMA activated PBL after cross-linking with goat anti mouse Ig, while the effect induced by E16.5 mAb after cross-linking was consistently lower. Finally, it was found that Sepharose-linked C1.18 mAb, in the presence of rIL-2 or PMA, did not induce TNF release from 6 NK cell clones.

Antibodies, Monoclonal↗

PubMedDate not supplied

Human interleukin-2 promotes proliferation of activated B cells via surface receptors similar to those of activated T cells.

Human interleukin-2 (IL-2) is a glycoprotein of relative molecular mass (Mr) 15,000, which is released by T lymphocytes on stimulation with antigen or mitogen and functions as a T-cell growth factor (TCGF) by inducing proliferation of activated T cells. It is generally accepted that resting or activated B cells do not respond directly to IL-2 but require for their proliferation other T-cell-derived lymphokines usually referred to as B-cell growth factors (BCGFs). Recently, however, a monoclonal antibody reacting with the IL-2 receptor molecules expressed by activated T cells (anti-Tac) was shown to react also with certain B tumour cells; in addition, murine B cells proliferate in response to pure human IL-2. We now show that recombinant IL-2, derived from Escherichia coli expressing the human gene, is able to promote strong proliferation of human B cells activated with protein-A-rich Staphylococcus aureus Cowans strain I. Moreover, we demonstrate that the anti-Tac antibody also reacts with S. aureus-activated normal B cells and inhibits sharply the proliferative response of such cells to IL-2. Finally, immunoprecipitation experiments reveal that anti-Tac defines similar molecules on activated T and B cells.

Animals↗