Cristina Cernetti

Activation of cord T lymphocytes: II. Cellular and molecular analysis of the defective response induced by anti-CD3 monoclonal antibody

Despite the fact that the percentage of circulating CD3-positive cells is similar in cord and adult blood, the proliferative response induced by anti-CD3 monoclonal antibody (mAb) was impaired in the majority of human cord peripheral blood mononuclear cell (PBMC) samples we tested. The cell proliferative defect was associated with low interleukin 2 (IL 2) gene expression and scant IL 2 production. However, interleukin 2 receptor was fully expressed at both the mRNA and protein levels. Such a finding is consistent with the observation that exogenous recombinant IL 2 is able to boost the anti-CD3-mediated response of cord PBMC. Furthermore, when anti-CD3 and phorbol myristate acetate (PMA) were added together, they exerted a very marked synergistic effect on both the proliferation of, and IL 2 production by, cord PBMC. The addition of allogeneic antigen presenting cells plus soluble anti-CD3 or Sepharose-coupled anti-CD3 mAb to the cord T cell cultures had no significant effect on proliferation, whereas both elicited good mitogenesis of adult T cells. Moreover, addition of exogenous recombinant interleukin 1 to anti-CD3-stimulated T cells failed to trigger any proliferation in either adult or cord samples. Since the combination of PMA and calcium ionophore A23187 is effective in triggering optimal proliferation of cord T cells, the defect would seem to be associated with a failure in transmembrane transduction of the activation signals provided by the anti-CD3 stimulus for the cord T cell.

Phenotypic dissection of cord blood immunoregulatory T-cell subsets by using a two-color immunofluorescence study

Expression of TQ1(Leu8) and 2H4 antigens on human cord blood T-cell subsets was evaluated by a double immunofluorescence analysis. In normal adult blood all of the helper function for B-cell differentiation is confined to the smaller OKT4+TQ1-(Leu8-) cell subset, while the OKT4+TQ1+(Leu8+) cell subpopulation includes a subset of suppressor inducer 2H4+(JRA+) cells. Our results indicated that the OKT4+TQ1-(Leu8-) cell subpopulation was decreased and the reciprocal OKT4+TQ1+(Leu8+) cell subset was markedly increased in cord blood E-rosetting OKT3+ cell population. A rise in the number of cord OKT4+2H4+ cells was also found. In addition, TQ1 antigen was present on OKT3+E-, a less mature, cord T-cell subset, not present in adult blood. These findings may not only be of help in understanding lymphoid cell development during ontogeny, but also may agree with the reported strong-suppressor and weak-helper activities exerted by the T-cell subsets circulating in human cord blood.

Phenotypic and functional abnormalities of T lymphocytes in pathological hyperprolactinemia

The phenotype and function of T cells circulating in patients with pathological hyperprolactinemia were analyzed and compared to those in sex- and age-matched control subjects. Two-color immunofluorescence study revealed an increased number of CD4+ TQ1+ cells and the presence of phenotypically immature CD1+ T cells, also exhibiting transferrin surface receptor, in peripheral blood of the hyperprolactinemic patients. After chronic treatment with the dopamine agonist bromocriptine, T-cell abnormalities disappeared. In addition, some untreated patients showed enhanced T-cell suppressor activity in anin vitro pokeweed mitogen-driven B-cell transformation assay. These immunological findings confirm a link between neuroendocrine and immune systems in humans.

Interleukin-6 is constitutively produced by human CTL clones and is required to maintain their cytolytic function☆

Maturation of cytolytic T lymphocytes from nonlytic precursors requires cytokines in addition to IL2. Interleukin-6 is the principal cytokine that cooperates with IL2 in the induction of CTL differentiation from murine and human thymocyte precursors. However, a cytotoxic differentiation factor (CDF) role of IL6 for mature T cells is challenged by data indicating that IL2 alone is sufficient for CTL generation. The aim of this study was to identify a model system in which IL6 acted as a CDF for human peripheral T cells. We noted that IL6 was endogenously produced by CTL clones in the course of their expansion with APC, lectin, and IL2. The majority of several hundred T-cell clones, both CD4+ and CD8+, produced IL6 in response to relatively high doses of IL2. Other experiments that compared the cytolytic function of CTL clones cultured in the presence of IL6 with that of the same clones cultured in the absence of IL6 demonstrated that IL6 contributes to the cytolytic ability of the majority of human CTL clones. Our data suggest that IL6 acts in an autocrine fashion to support CTL differentiation in human T-cell clones.

Evidence for phenotypic t precursor cells in human cord blood.

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A mature thymocyte-like phenotypic pattern on human cord circulating T-lymphoid cells

Cord blood samples from healthy full-term newborns were tested with antimature and antiimmature lymphoid-cell monoclonal antibodies, as well as more traditional markers, in order to identify the phenotype of circulating precursor cells. The results demonstrated that human cord blood contains a lower number of OKT3+, E-rosetting mature T cells than adult blood, very high levels of OKT10+ cells, and few OKT9+, OKT8+OKT3−, and OKT4+OKT3− cells. Although the finding of OKT9+ and OKT10+ cord circulating cells could be indicative of cell activation, double marker studies in newborn blood pointed to phenotypically immature lymphoid subsets at different stages of maturation, according to Reinherzs hypothesis. In addition, the absence of nuclear Tdt-positive and hot-rosetting cells, together with the fact that most of these are OKT3+, OKT10+, OKT4+, or OKT8+ cells, suggests that the surface phenotype of newborn lymphocytes is similar to that of mature thymocytes.

The in vitro effect of a calf thymus extract (thymostimulin) on the immunologic parameters of patients with untreated Hodgkin's disease

The in vitro effect of a calf thymus extract, thymostimulin (TP‐1), on the E‐rosette‐forming capacity and on the PHA blastogenic response of peripheral blood lymphocytes was evaluated in 20 patients with untreated Hodgkins disease. The mean percentage of lymphocytes forming E rossettes increased in patients from 44.2% to 57.5% (P < 0.005). The mean PHA stimulation index rose with all three concentrations tested, but returned to the normal range only with the highest PHA concentration (60 μ/ml). An increase in the immune parameters was greatest in those patients who presented with decreased E‐rosetting cells or total lymphocyte counts or whose disease was Stage III or IV or of mixed cellular histology.

Monoclonal antibody-defined T-cell phenotypes and phytohemagglutinin reactivity of E-rosette-forming circulating lymphocytes from untreated chronic myelocytic leukemia patients

T‐cell phenotypes, as defined by murine monoclonal antibodies, (OKT3, OKT4, OKT8, OKIaI), and phytohemagglutinin (PHA) reactivity, were evaluated in E‐rosette forming cells (T‐cells) from 10 untreated chronic myelocytic leukemia patients. The proportion of T4+ cells was lower in patients than in controls (41.6 versus 61.7%, P < 0.02); whereas the proportion of T8+ cells was similar in patients and controls. The decrease in T4+ cells in CML resulted in a decrease in circulating T4+/T8+ ratio (P < 0.02). The la1+ T‐cells were increased in most CML (8 of 9) patients, white control subjects never displayed la1+ T‐lymphocytes (P < 0.01). The PHA reactivity of E‐rosette forming lymphocytes was significantly impaired in CML patients with respect to controls (P < 0.02). The presence of la antigen on T‐cells was positively correlated with the T8+ cell phenotype (P < 0.001) and inversely correlated with the T4+ (helper) cell phenatype (P < 0.05). Furthermore, there was a trend towards an inverse correlation between the PHA response and the level of lal+ or T8+ cells, there is no correlation between PHA reactivity and T4+ phenotype. The results suggest that the T‐lymphocyte population from untreated CML patients is intrinsically abnormal.

X-ring Turner’s syndrome with combined immunodeficiency and selective gonadotropin defect

A rare association of chromosomal, immunological and endocrine defects is described in a young woman with short stature, recurrent pulmonary infections and primary amenorrhea. Cytogenetic studies showed a 45, X karyotype in 65% of peripheral blood lymphocytes and 46,Xr(X) (p22q27) karyotype in the remaining 35%. Severe immunodeficiency was revealed by phenotypical and functional studies and a selective gonadotropin defect was disclosed by endocrinological investigations. An attempt is made to explain the coexistence of the three abnormal pictures.

Isolation and partial characterization ofCupressus sempervirens allergens

SummaryAllergic rhinitis due to cypress pollen is a well-recognized clinical condition that is evermore frequently diagnosed as a winter allergy in the Mediterranean area. Little is known about the allergen composition of its pollen and the dynamics of its immune response. For these reasons IgE-specific antibody distribution was determined and the allergenic pollen characterized. SDS-PAGE analysis of the whole extract revealed more than ten proteic bands ranging from 10 to 90 kD. The major allergen had a molecular weight of 36 kD and the specific IgE antibody was presene in >95% of the sera tested by immunoblotting technique. Two minor allergens were observed at the 43 and 49 kd protein bands. The results obtained with the whole extract were then compared to those of five commercially available preparations.