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D M Parrott

Publications and source records attributed to D M Parrott.

85 records · Page 5Linked to original sources
PubMed1969

Induction and recall in contact sensivitity. Changes in skin and draining lymph nodes of intact and thymectomized mice.

The cellular events in the ear skin and draining lymph node during the induction of contact sensitivity to 2-ethoxy methylene-5-oxazolone (oxazolone) have been studied in three strains of mice. The principal findings in the skin during the first 24 hr were invasion of polymorphs and destruction of pilosebaceous units, in both intact and thymectomized mice. Subsequently, the dermal cellular infiltrate increased and there was acanthosis of the epidermis. No lymphocytes were seen in the dermis or penetrating the epidermal basal cell layer in thymectomized mice. During the first 24 hr in the draining node, polymorphs and macrophages bearing a pigment with staining properties similar to melanin were seen in the marginal and medullary sinuses, in intact and thymectomized mice. Major differences, however, were revealed during 2-4 days when massive proliferation of large pyroninophilic blast cells occurred in the thymus-dependent area of the nodes from intact mice only. On testing, there was a prompt, measurable increase in ear thickness only in intact mice. This increase reached a peak at 24 hr - typical of a delayed type reaction. At testing, the ears from intact mice showed epidermal vesiculation and a considerable dermal cellular infiltrate with a substantial number of lymphocytes. This was in contrast with the completely quiescent appearance of the ear skin of thymectomized mice. Finally, we have discussed the use of the mouse as an experimental tool for studying contact sensitivity and have analyzed the role of the thymus-derived lymphocyte and the site where it becomes sensitized, in the light of current theory on the origin of cells and site where sensitization takes place in cell-mediated reactions.

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The immunological consequences of nematode infection.

Nematode infections in the gut induce a strong immune response which is rapidly detected parenterally. The response is thymus-dependent and long-lasting and involves both antibodies and cell-mediated reactions. The immunological response to unrelated antigens, tumours and other infectious organisms is altered in animals infected with nematodes. Both antibodies and sensitized lymphocytes participate in the immune response which affects the nematodes themselves, and characteristically the lymphocyte-dependent step cannot act in lactating animals and is neither induced nor able to act in young animals. Present evidence suggests that, despite their well-known association with helminth infections, parasite rejection from the gut does not require the participation of IgE antibodies, mast cells or eosinophils. Homing of lymphoblasts from the mesenteric lymph node or thoracic duct lymph to the small intestine is increased in rats and mice infected with Nippostrongylus brasiliensis or Trichinella spiralis and the increase is antigenically non-specific. In mice infected with T. spiralis this increase is represented mainly by thymus-derived lymphoblasts.

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