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Biomedical subjects

R Vaccaro

Publications and source records attributed to R Vaccaro.

At least 73 records · Page 4Linked to original sources
PubMed1984

Immunoregulatory T cells in measles. The relationship between reduced lymphocyte proliferative response to PHA and increased proportion of circulating suppressor-cytotoxic T cells.

Viral infections are often associated with immunodeficiency states. Although T lymphocytes have been thought to suppress the host's immune response, the precise cellular basis for this phenomenon remains unclear. Therefore, we characterized peripheral blood mononuclear cells from 9 measles virus-infected children by means of monoclonal antibodies directed against surface antigens expressed on human T lymphocytes and T-cell subsets. In addition, the measles lymphocyte blast transformation response to the T-cell mitogen phytohaemagglutinin (PHA) was evaluated as an index of specific T-cell immunocompetence. During the course of measles, there was a slight reduction in the proportion of total circulating T cells, with a relative decrease in helper-inducer and a parallel increase in suppressor-cytotoxic T lymphocytes. The PHA lymphocyte blastogenic response was found to be defective in children with measles and, interestingly, there was a significant negative correlation between the reduced PHA blast transformation value and the increased proportion of suppressor-cytotoxic cells. The biological implications of these finding with respect to the underlying immunopathology of the measles virus infection are discussed.

Antibodies, Monoclonal↗
PubMed1984

Lymphocyte surface phenotypes in Down's syndrome.

The lymphocyte surface phenotypes in the blood of 7 non-institutionalized adults with trisomy-21, and in 10 karyotypically normal control subjects, were analysed by fluorescent microscopy with an OKT series of monoclonal antibodies. Whereas the proportions of OKT3+, OKT4+ and OKT6+ cells were similar in the two groups, the percentages of both OKT8+ and OKT10+ trisomic lymphocytes were significantly higher. The biological implications of these findings with respect to the underlying immunopathology of Down's syndrome are discussed.

Adult↗
PubMed1984

Phenotypic analysis of T cell subsets in the blood of chronically aborting women.

A relative decrease in helper and a parallel increase in suppressor-cytotoxic T lymphocytes was found in the blood of six habitually aborting women, as compared with the T-cell subset distribution in ten normal multiparae and eight multigravid post-partum women. It is suggested that an imbalance between the immunoregulatory T-cell subpopulations may contribute to the rejection of the semiallogenic fetus.

Abortion, Habitual↗
PubMed1983

Monoclonal antibody-defined T-cell surface phenotypes in human breast milk.

The distribution of T-lymphocyte subsets in human early milk was determined by immunofluorescence analysis of reactivity with monoclonal antibodies of the OKT series. A novel finding was that the T-lymphocyte population in human milk contains both OKT4 (helper/inducer phenotype) and OKT8 (suppressor/cytotoxic phenotype)-positive subsets. The relative ratio of OKT4 to OKT8-positive T-cell subsets in milk, however, was generally higher than that observed for peripheral blood T cells.

Female↗
PubMed1983

Serum migration inhibitory activity and monoclonal antibody-defined T-cell phenotypes in patients with acute infectious mononucleosis.

Previous experiments in our laboratory have demonstrated that circulating endogenous leucocyte (migration) inhibitory factor (serum LIF), or a lymphokine with LIF-like activity, may be involved in the impaired cellular immune response observed during the acute phase of the Epstein-Barr virus (EBV) induced infectious mononucleosis (IM). To determine whether serum LIF activity is associated with immunoregulatory IM T-cell subset abnormalities, we analyzed the peripheral blood T-cell populations in a series of acute serum LIF-positive and LIF-negative IM patients by means of T-lymphocyte-specific monoclonal antibodies. Although there was both activation and increase of suppressor/cytotoxic T cells in all IM patients sampled in the acute stage, the relative and absolute numbers of suppressor lymphocytes were found to be significantly higher in those who had LIF activity in their serum. It is postulated that EBV infection can preferentially activate a specific T-cell subpopulation which, in its turn, inhibits the overall host immune response, possibly by a LIF-induced feedback suppression mechanism.

Antibodies, Monoclonal↗
PubMed1983

"In vitro" and "in vivo" leukocyte migration inhibitory factor production in acute infectious mononucleosis patients.

Since infectious mononucleosis (IM) mononuclear cells spontaneously release the leukocyte (migration) inhibitory factor (LIF) in culture and since previous experiments in our laboratory have demonstrated that one or more substances with LIF-like activity are detectable in the serum (serum LIF) of young patients with heterophile-positive IM, an investigation was carried out to determine both the in vitro and in vivo LIF production in a series of IM patients sampled during the acute phase of the infection. The observation than only the unstimulated lymphocytes from serum LIF-positive IM patients released LIF in culture suggests that a single active product is involved in the in vitro and in vivo LIF activities observed in Epstein-Barr virus (EBV) infected subjects. The biological implications of this finding with respect to the underlying immunopathology of the EBV IM syndrome are discussed.

Adolescent↗
PubMed1982

Leucocyte migration-inhibitory activity in human cord blood.

Leucocyte migration-inhibitory activity was found in the sera (cord blood) of 15/28 (53%) healthy, fullterm newborn infants as opposed to only 3/28 (10,7%) control children under three years of age (P less than 0,005). It is postulated that the migration-inhibitory activity may be related to lymphokine-dependent mechanisms.

Child, Preschool↗
PubMed1981

Serum migration-inhibitory activity in infants with respiratory syncytial virus bronchiolitis.

Using an unidirectional leucocyte migration-inhibition (LMI) assay, we investigated the migration-inhibitory activity (LIF) in the sera of 25 infants who developed bronchiolitis following respiratory syncytial virus (RSV) infection. Blood samples for serum-LIF activity detection were obtained from patients the day after admission and two weeks later. The LMI assay revealed serum-LIF activity in 17 (68%) blood samples taken during the acute phase of the disease. In contrast, no inhibition was found in the convalescent blood samples with the exception of 5 (20%). This difference was statistically significant (chi2 = 9.82; P less than 0.005). As positive serum-LIF test is a good in vitro correlate of cell-mediated immunity, our results suggest that cell-mediated hypersensitivity reactions occur during the clinical course of RSV bronchiolitis. These findings are consistent with the hypothesis that alterations of RSV-specific cell-mediated immune mechanisms may be involved in the pathogenesis of this illness.

Bronchiolitis, Viral↗
PubMed1976

Clinical experience in detecting endotoxemia with the limulus test in typhoid fever and other Salmonella infections.

Semiquantitative estimates of circulating endotoxin were performed by the limulus test in patients suffering from typhoid fever and other salmonelloses. The test was positive in a large number of cases. However, no clearcut correlation was found between existence of endotoxemia, as such, and pyrexia. A correlation with recent bacteremia was found for highest levels of endotoxin activity. In minor salmonelloses a striking prevalence of positive cases was observed in the age group under one year. These findings were discussed in relation to the diagnostic and pathogenetic facets of the problem.

Adolescent↗