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A Coutinho

Publications and source records attributed to A Coutinho.

388 records · Page 22Linked to original sources
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A novel cell surface molecule on early B-lineage cells.

B cells and their antibody-secreting progeny represent one of several differentiation pathways that haematopoietic stem cells (HSC) may enter. Cells representing intermediate stages between HSC and B cells have been identified in mammalian haematopoietic tissues and studied intensively over the past decade. This population of early B-lineage cells, termed pre-B, is characterized by cellular proliferation and an orderly cascade of immunoglobulin gene rearrangements, a combination of events leading to the generation of clonally diverse B cells which then migrate to peripheral lymphoid tissues. It remains to be determined what elements determine the polyclonal growth of pre-B cells, how immunoglobulin gene rearrangements are regulated, and what happens to pre-B cells undergoing 'non-productive' immunoglobulin gene rearrangements. These issues could be resolved more easily if early B-lineage cells could be identified precisely and isolated. Here, we describe a cell surface glycoprotein that is selectively expressed by pre-B and newly formed B cells in murine haematopoietic tissues. The molecule, a homodimer formed by disulphide-linked chains of relative molecular mass (Mr) 140,000, is identified by a mouse monoclonal alloantibody called BP-1.

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The membrane receptor complex regulating induction and clonal expansion of normal murine B lymphocytes.

Induction of resting B lymphocytes results from the interaction of competent ligands or helper cells with "triggering receptors." Subsequent clonal expansion and performance are thought to be regulated by the interaction of selective growth or maturation factors with specific receptors on induced B cells. A set of membrane molecules of B lymphocytes, including IgM, IgD, IA, IE, lipopolysaccharide receptors, receptors for Fc and C3b, and other non-immunoglobulin structures recognized by some antiidiotypic antibodies, display ligand-induced relationships. Functional studies also indicate that this group of molecules functions as a complex that regulates delivery of inductive signals, the expression of growth and maturation receptors, and/or the outcome of the interactions of these receptors with the corresponding factors.

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[History of lymphatic filariasis in Pernambuco. I. Epidemiologic and control aspects].

This paper is a review of lymphatic bancroftian filariasis in the State of Pernambuco. Brazil. It shows that reports have existed since the 1st decade of the century. Knowledge of the disease in several areas during different periods makes a retrospective analyses very interesting, particularly in Great Recife. It is in the city that the epidemiological and control aspects of the diseases are examinations in details.

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[Clinical manifestations of lymphatic bancroftian filariasis].

A review of clinical manifestations of bancroftian filariasis, based on the literature and in the authors' experience, suggests a general classification in to six groups: 1) Normal endemics; 2) Individuals bearing microfilaremia; 3) Acute manifestations; 4) Chronic manifestations; 5) Tropical Pulmonary Eosinophilia; 6) Controversial forms. An overview on diagnostic procedures and the immunologic relationship between host and parasite was made in each group. Final considerations about treatment was also considered.

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Analysis of autoantibody reactivities in hybridoma collections derived from normal adult BALB/c mice.

Hybridoma collections were produced from lipopolysaccharide-stimulated adult BALB/c spleen cells, small resting spleen B cells and large activated spleen lymphocytes. The hybridomas were examined for production of immunoglobulins and of antibodies directed against a panel of self (actin, myosin, tubulin, DNA) and non-self antigens (myoglobin, spectrin, trinitrobenzene). From the 345 hybridomas secreting immunoglobulin, 68% did not react with any antigen of the panel, 17% reacted with only one, 5.5% with 2 and 7.9% with 3 or more. Apparently, each of the monoclonal multispecific antibodies exhibited a pattern of reactivity which was quite unique. There were no apparent differences in antibody reactivities between self and non-self antigens; moreover, with the exception of DNA, no differences were noted among the 3 different hybridoma collections.

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The self-nonself discrimination and the nature and acquisition of the antibody repertoire.

Network ideas are confronted with current hypotheses for the origin of antibody diversity and self-nonself discrimination. The difficulties of reconciling the promethean evolution of the antibody system with "germ line" theories are discussed, as well as the problems of "somatic" hypotheses to explain the completeness of the antibody repertoire. The formal incompatibility of the network theory with ideas basing self-nonself discrimination on the elimination of self-reactive cells is demonstrated, as well as the difficulties of these and other environment-dependent hypotheses for lymphocyte activation, to encompass the internal activity in the immune system. It is argued, on the other hand, that the limitations of the network theory in providing a functional basis for the idiotypic network and in accounting for self-nonself discrimination, can be solved by finding in a complete repertoire of antibody-combining sites the complementary structures to growth receptors on B lymphocytes, and by using these as internal mitogens in the expansion of the precursor cell pools and in the maintenance of the mature steady states. Letting self-nonself discrimination be accounted for by such growth receptors, both the integrity of the antibody repertoire and the internal activity in the system can also be ensured. Moreover, by postulating a germ line origin for the antireceptor antibodies and by accepting idiotypic cross-reactivity between growth receptors and other germ line antibodies, the possibilities are set for a phylogenetically and ontogenically autonomous immune system embodied with the capabilities for self-expansion, diversification and selection of available repertoires. Its promethean characteristics are explained by its completeness, and this is achieved by idiotypic interactions between growth receptors and a limited number of complementary or cross-reactive germ line antibodies, naturally selected on the basis of their structural relationships with growth receptors.

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