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G Mayrhofer

Publications and source records attributed to G Mayrhofer.

81 records · Page 5Linked to original sources
PubMed1979

A method for specifically detecting internal immunoglobulin by immunofluorescence.

The detection of specifically internal immunoglobulin by staining of fixed preparations of lymphoid cells with appropriate fluorescein-conjugated antisera can be hampered by binding of the conjugates to membrane-bound immunoglobulin. Without preventing staining through membrane-bound immunoglobulin, it is impossible to be sure whether lightly stained cells contain only small amounts of immunoglobulin or wehter the staining is entirely due to the membrane-bound material. Surface immunoglobulin can be stripped from tonsil cells prior to making preparation, and this can be achieved without loss of viable cells. As compared with untreated preparations, pronase-stripped smears contain little non-cellular debris and greatly reduced numbers of small lymphocytes faintly stained by polyvalent anti-human immunoglobulin. The remaining stained cells can be said to specifically contain internal immunoglobulin and are easily scored.

Cell Survival↗
PubMed1979

Mast cells in severely T-cell depleted rats and the response to infestation with Nippostrongylus brasiliensis.

The effect of severe T-cell depletion on mucosal mast cells of the small intestine and on connective tissue mast cells has been studied in adult thymectomized, irradiated, bone marrow reconstituted (B) rats. Under normal conditions, intestinal mucosal mast cell numbers do not differ significantly between B rats, normal age matched rats and non-thymectomized irradiated controls. Connective tissue mast cells are significantly fewer in the tongues of B rats than in normal rats, but the difference is atributable to an effect of irradiation. Infestation with Nippostrongylus brasiliensis produced approximately equal increases in mucosal mast cells in non-thymectomized irradiation controls and in normal rats. In B rats there was no increase in mucosal mast cells following infestation. B rats failed to expel the parasites normally. Failure of mast cell proliferation was not due to the effects of the persisting worm burden. Antihelminthic treatment at the time of worm expulsion by normal rats did not reveal a hitherto masked mast cell response in B rats. Nippostrongylus infestation did not reveal evidence of thymus-dependency of connective tissue mast cells. As in athymic nude mice, mucosal mast cells in the rat have been shown to be T-cell dependent during the proliferation that follows infestation with an intestinal nematode parasite.

Animals↗
PubMed1976

Nature of cells binding anti-IgE in rats immunized with Nippostrongylus brasiliensis: IgE synthesis in regional nodes and concentration in mucosal mast cells.

The possibility that IgE is a secretory immunoglobulin has been examined by studying the tissue and cellular localization of IgE in rats infested with the enteric parasite, Nippostrongylus brasiliensis. The lamina propria of the small intestine and the colonic and pulmonary mucosal surfaces contained numerous anti-IgE-binding cells, but these were shown to be mast cells and not plasma cells. The major site of IgE synthesis was the regional lymph node of the small intestine, the mesenteric node, which contained large numbers of IgE-secreting plasma cells. Smaller numbers of IgE-secreting plasma cells were also found in the axillary node, which drained the site of larvae injection. Peyer's patches, the intrapulmonary bronchial lymphoid tissue and the spleen contained few, if any, IgE-secreting plasma cells. The significance of the IgE which was readily demonstrated in germinal centers of the mesenteric lymph nodes, the Peyer's patches and the axillary lymph nodes, is not known. In contrast to the infested animals, the lymphoid organs of normal rats rarely contained any IgE-CONTAINING CELLS; An unexpected observation was that mast cells in mucosal organs appear to contain intracellular IgE, differing in this respect from connective tissue mast cells. Mast cells lying between epithelial cells, the "globule leukocytes", also appear to contain intracellular IgE, and it is suggested that such cells may be responsible for the presence of IgE in exocrine secretions. This study does not support the suggestion that IgE is a secretory immunoglobulin with a physiology analogous to that of IgA.

Animals↗
PubMedDate not supplied

Sites of synthesis and localization of IgE in rats infested with Nippostrongylus brasiliensis.

The tissue and cellular localization of IgE has been studied in normal rats and rats infested with the enteric parasite, Nippostrongylus brasiliensis. The results of the study do not support the suggestion that IgE is a secretory immunoglobulin with a physiology analogous to that of IgA. The lamina propria of the small intestine and the colonic and pulmonary mucosal surfaces contain numerous anti-IgE-binding cells, but these have been shown to be mast cells and not plasma cells. The major sites of IgE synthesis were the regional lymph nodes of the small intestine and the lungs, which contained large numbers of IgE-secreting plasma cells. Smaller numbers of IgE-secreting plasma cells were also found in peripheral lymph nodes, some of which were distant from tissues known to have direct contact with either larvae or adult worms. Peyer's patches, the intrapulmonary lymphoid tissue and the spleen contained few, if any, IgE-secreting plasma cells. The significance of the IgE which was readily demonstrated in germinal centres of Peyer's patches and several lymph nodes is not known. In contrast to infested animals, the lymphoid organs of normal rats rarely contained any IgE-containing cells. Thoracic duct lymph from infested animals contained only few IgE-containing large lymphocytes, similar in number to cells containing IgM or IgG but only 1/50 as many as those containing IgA. An unexpected observation was that mast cells in mucosal organs appear to contain intracellular IgE, differing in this respect from connective tissue mast cells. Mast cells lying between epithelial cells, the 'globule leucocytes', also appear to contain intracellular IgE and it is suggested that such cells may be responsible for the presence of IgE in exocrine secretions. This study highlights the need for careful identification of cells appearing to contain IgE and suggests reasons for the widely differing reports of the numbers of IgE-secreting plasma cells in human intestinal biopsies.

Animals↗
PubMedDate not supplied

Genetic analysis of Giardia from hoofed farm animals reveals artiodactyl-specific and potentially zoonotic genotypes.

Thirty one Giardia isolates, established from six species of hoofed livestock by axenic culture or growth in suckling mice, were compared genetically by analysis of DNA amplified from loci encoding variant surface proteins or the enzyme glutamate dehydrogenase and by allozyme analysis. The isolates were heterogeneous, but all showed affinity with genetic Assemblage A--one of two major assemblages defined previously by analysis of Giardia from humans. Three distinct genotypes were evident. Ten isolates (eight axenic and two established in suckling mice) from an alpaca, pig, horse, cattle and sheep were indistinguishable from human-derived G. intestinalis belonging to a previously designated genetic group (Group I). This genotype seems to have broad host specificity, including a zoonotic potential for humans. Five isolates (two axenic and three established in suckling mice) from an alpaca, a horse and sheep had close affinity with human-derived Group I and Group II G. intestinalis genotypes. The other 16 isolates (comprising both axenic and suckling mouse-propagated cultures derived from cattle, sheep, alpaca, a goat and pigs in Australia and Europe) differed from all other Giardia with "duodenalis" morphology that have been examined by these methods and they segregated as a highly distinct sublineage (referred to herein as 'Novel livestock') within genetic Assemblage A. The predominance of 'Novel livestock' genotypes in the test panel and their apparent exclusive association with artiodactyl hosts indicates that they may be confined to this group of mammals. Assemblage B genotypes, which are prevalent in humans and some other animal species, were not detected.

Animals↗