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D Befus

Publications and source records attributed to D Befus.

46 records · Page 3Linked to original sources
PubMed1984

Gut- and bronchus-associated lymphoid tissue.

Bronchus-associated and gut-associated lymphoid tissues (BALT and GALT) have both functional and morphologic similarities and are involved in seeding lung, gut, and other mucosal sites with predominantly IgA-containing B cells. Both types of lymphoid tissue are engaged in the regulation and the controlled amplification of immune responses, which vary from positive mucosal responses in both mucosae and peripheral tissues to local mucosal responses and systemic tolerance. Their further involvement in provision of cells destined to reside in the epithelial compartment of the body appears likely but requires further investigation. Their role in the provision of precursors of mucosal mast cells must also be explored further, but some participation in this event appears likely. The mucosa-associated lymphoid tissue (MALT) system appears to be integrated with the systemic immune system but may be considered as separate from it in several functional ways.

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PubMed1984

Broncho-alveolar leucocyte responses during primary and secondary Nippostrongylus brasiliensis infection in the rat.

Using broncho-alveolar lavage, we have studied the cellular responses in the rat lung following primary and secondary infection with Nippostrongylus brasiliensis. During the primary infection, there was a biphasic increase in total broncho-alveolar leucocytes and in the absolute numbers of macrophages, neutrophils, eosinophils and lymphocytes. The first peak occurred on days 4-6, and the second peak occurred around day 16, after infection. During the secondary infection there was an anamnestic-like response by all cell types. These data suggest that the broncho-alveolar leucocyte responses to infection have an immunological basis and that in addition to the alveolar macrophage, neutrophils, eosinophils and lymphocytes may play a significant role in lung resistance against migrating helminth larvae.

Animals↗
PubMed1984

Mast cell heterogeneity and hyperplasia in bleomycin-induced pulmonary fibrosis of rats.

The distribution, density, and histochemical subtype of mast cells were studied in the respiratory tract of rats with bleomycin-induced pulmonary fibrosis. In normal rats, mast cell densities were highest in the trachea and lowest in the bronchus and parenchyma. Two histochemically distinct mast cell populations were identified in the mucosa adjacent to the tracheal cartilage, but elsewhere only a single population of typical connective tissuelike mast cells was found. After intratracheally administered bleomycin, lung histamine levels (micrograms/g wet weight) increased as much as 14-fold by Day 50. Pulmonary mast cell changes were present early in the fibrotic process, and by Day 14 the mast cell density in the parenchyma was 10 times normal. These parenchymal mast cells were histochemically of the connective tissue type. Thus, pronounced mast cell hyperplasia occurs during the evolution of experimental pulmonary fibrosis. This model provides a powerful tool to study pulmonary mast cells and to identify their role in fibrotic disease.

Animals↗
PubMed1984

Expression of IgE receptors and histamine in cloned natural killer cell lines.

Natural killer (NK) activity is mediated by large granulated lymphocytes (LGL). Recently, the relationship of NK cells to mast cells and basophils has been suggested. We therefore examined three distinct interleukin 2-dependent cloned cell lines capable of mediating NK lysis. Virtually all the cells of each line contained membrane-bound granules. Interestingly, ultrastructural studies demonstrated that the granules in each cell line were morphologically distinct and thus heterogeneous. All three cloned, granulated NK cell lines were found to variably express low numbers (less than or equal to 1.3 X 10(4)) of low affinity plasma membrane IgE receptors (Fc epsilon R). In contrast to mast cells and basophils, however, none were found to express high numbers of high affinity Fc epsilon R. In addition, none of the three NK cell lines were found to contain histaminase-sensitive histamine. Our results suggest that NK cells are not related to mast cells or basophils.

Animals↗
PubMed1984

Complement-dependent killing of Nippostrongylus brasiliensis infective larvae by rat alveolar macrophages.

Histopathological studies have provided circumstantial evidence that helminth parasite destruction occurs in the lung; however controlled in vitro studies on the helminthocidal activity of lung cells have not been reported. This study presents evidence that Nippostrongylus brasiliensis infection in the rat induces alterations in broncho-alveolar lavage (BAL) cell numbers, differential counts, and in vitro helminthocidal activity. Normal, uninfected rats yielded 3.3 +/- 0.6 X 10(6) BAL cells/rat, consisting predominantly of alveolar macrophages (greater than 90%). However on days 2-8 post-infection there was a 1.5-2.4-fold increase in BAL cell numbers with a significant neutrophilia on day 2 and a significant increase in the absolute number of all cell types on day 8. On day 32 post-infection, BAL cell numbers had returned to control levels. Normal BAL cells neither adhered to nor killed N. brasiliensis infective larvae (L3) in the presence of rat complement. By contrast BAL cells recovered from infected rats on days, 2, 8 or 32 post-infection (D2, D8 and D32 BAL cells, respectively) adhered under similar conditions. However, only D8 and D32 BAL cells killed L3. This complement-dependent killing correlated with significantly increased numbers of C3 receptor bearing alveolar macrophages in D8 and D32 BAL cells. Complement-dependent alveolar macrophage helminthocidal activity may therefore play an important role in lung resistance against resident or migrating helminths.

Animals↗
PubMed1983

Regulation of lymphoblast traffic and localization in mucosal tissues, with emphasis on IgA.

A fundamentally important factor in the expression of immunity at mucosal sites is the migration of primed lymphocytes to, from, and among mucosal tissues. Despite considerable information in recent years on the selective localization of B lymphoblasts, especially those destined to make IgA antibodies in mucosal tissues, the basis for this remains obscure. Several cell-associated factors such as surface characteristics, histo-compatibility type, and organ derivation of the cells play a significant role for T and B lymphoblast localization. Factors that regulate lymphoblast delivery to tissues, such as blood flow, or control emigration from tissues, such as arachidonic acid metabolites, are discussed. Finally, factors such as the presence or absence of high endothelial venules, isotype-specific T helper cells, sex hormones, antigen, macrophages, and iron all may play a significant role in mucosal lymphoblast localization.

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