Biomedical subjects

A Bensaid

Publications and source records attributed to A Bensaid.

60 records · Page 4Linked to original sources

PubMed1988

Characterization of a bovine thymic differentiation antigen analogous to CD1 in the human.

Three monoclonal antibodies (MoAb), TH97A, CC13, and CC14, define a thymic differentiation antigen in cattle. The antigen is expressed on 50-60% of bovine thymocytes, located mainly in the cortical areas, but is not expressed on peripheral blood mononuclear cells (PBMC). In cryostat sections of lymph node, the antibodies react with large dendritic-like cells in the paracortical regions. They also react with a proportion of the large 'frilly' cells in afferent lymph and with dendritic-like cells in the dermis. The antibodies apparently do not react with cells in the epidermis. Biochemical analysis of the antigen recognized by MoAb TH97A reveals two bands of 44 kDa and 12 kDa under reducing conditions. These polypeptides are distinct from bovine class I major histocompatibility complex molecules reactive with the MoAb w6/32. The tissue distribution of positive cells together with results of biochemical analyses indicate that the antigen recognized by these MoAb is the bovine analogue of the human CD1.

Animals↗

PubMed1986

Bovine cytotoxic T-cell clones specific for cells infected with the protozoan parasite Theileria parva: parasite strain specificity and class I major histocompatibility complex restriction.

We present information on the specificity of three bovine cytotoxic T-cell clones reactive with lymphoblasts infected with the protozoan parasite Theileria parva. The clones were derived from peripheral blood mononuclear cells of an animal immunized with T. parva (Muguga stock), after five stimulations in vitro with an autologous parasitized cell line. The three clones belonged to the BoT8+ subset of T cells, which is similar to the human CD8+ T-cell subset. On the basis of analysis on a panel of infected target cells originating from cattle of different major histocompatibility complex (MHC) phenotypes, killing by all three clones was found to be restricted to targets bearing the class I MHC specificity KN104, which is defined by alloantiserum KNA104 and monoclonal antibody IL-A4. This class I MHC restriction was confirmed by blocking of target cell lysis with these antibodies and monoclonal antibody w6/32, which reacts with a nonpolymorphic determinant on bovine class I MHC molecules. The three clones were parasite strain specific, in that they did not kill cells of the appropriate MHC type infected with T. parva (Marikebuni stock). These findings, taken together with previous observations that immunization of cattle with T. parva (Muguga) does not provide protection against challenge with T. parva (Marikebuni), suggest that the cytotoxic T cells recognize a cell surface antigen that may be important in induction of immunity to the parasite.

Animals↗

PubMed1986

Characterization by a monoclonal antibody and functional analysis of a subset of bovine T lymphocytes that express BoT8, a molecule analogous to human CD8.

Monoclonal antibody (mAb) IL-A17 characterizes a subset of bovine T lymphocytes. IL-A17 recognizes a 34,000-35,000 MW doublet, designated BoT8, which is expressed on the surface of approximately 20% of peripheral blood mononuclear leucocytes (PBM), a subpopulation of lymphocytes in T-dependent areas of lymph nodes and spleen, and about 70% of thymocytes. This molecule is not expressed on B lymphocytes, monocytes/macrophages or granulocytes. Double labelling of PBM showed that the BoT8+ population is distinct from the T lymphocyte subset expressing BoT4. BoT8+ lymphocytes purified with a fluorescence-activated cell sorter (FACS) proliferated poorly in response to mitogenic and alloantigenic stimulation in the absence of exogenous growth factors. IL-A17 had no inhibitory effect on proliferation of PBM to mitogens (Con A and PHA) or alloantigens and no measurable effect on the in vitro generation of cytolytic effector cells. However, in some experiments IL-A17 was found to block partially allospecific cytolytic function mediated by bulk effector cell populations when included in 51Cr-release assays. Fractionation of effector cells generated in an allogeneic mixed leucocyte culture (MLC) demonstrated that cytotoxic cells specific for class I major histocompatibility complex (MHC) antigens reside within the BoT8+ population. Based on these data, and information reported elsewhere on alloreactive bovine T-cell clones, BoT8 is considered to be analogous to CD8 in humans and equivalent molecules in other species.

Animals↗

PubMed1985

De novo expression of T cell markers on Theileria parva-transformed lymphoblasts in cattle.

We describe monoclonal antibodies that detect two new membrane antigens on bovine T cells. One molecule is only expressed on activated T cells and has a m.w. of 100,000. The other antigen is a glycoprotein that is precipitated as two bands of m.w. 150,000 and 158,000 and is expressed on a subpopulation of T cells and all myeloid cells. We show that when bovine lymphocytes are transformed by the protozoan parasite Theileria parva, both antigens become expressed on the cell surface. The infected cell acquires the phenotype of a proliferating T cell, irrespective of its precursor cell phenotype.

Animals↗

PubMed1982

[Sensitivity and specificity of lead poisoning detection tests].

The results of biochemical tests used for the supervision of factory workers exposed to lead (notably lead serum levels, urinary aminolevulinic acid (ALA) and punctuated red cells) were compared in 90 patients. The reference test used to evaluate the sensitivity and specificity of these examinations was EDTA-induced lead urinary excretion. Lead serum levels and urinary ALA were about equally effective in providing information. However, these two tests were more sensitive when performed simultaneously than when performed separately. It is suggested that both should be requested when trying to prevent lead poisoning.

Adult↗

PubMedDate not supplied

[Organization of the mental lexicon in 12 schizophrenic subjects].

Using different tasks to test the organization of the mental lexicon in schizophrenics patients we tried to confirm the non organization of their mental lexicon as underlied by different authors and to show a wrong exploitation of their semantic competences. Our findings pointed out the difficulties of the evaluated lexical competences exploitation rather than the disturbances of these competences themselves.

Adult↗