The athymic nude rat. IV. Immunocytochemical study to detect T‐cells, and immunological and histopathological reactions against Trichinella spiralis

Abstract

The anti-parasite response was investigated after oral infection of athymic nude (rnu/rnu) rats and heterozygous (+/rnu) littermates with 1000 muscle larvae of Trichinella spiralis. No IgM, IgG and IgE antibodies were detected in serum of rnu/rnu rats. Expulsion of adult worms from the small intestine was prolonged (worms were nearly all expelled at days 14 and 91 in +/rnu and rnu/rnu rats respectively). The yield of muscle larvae in the carcasses of nude rats at day 91 was 33 times higher than in +/rnu rats. In contrast to the strong inflammatory reaction in the parasitized tongue of +/rnu rats, no infiltration was observed in rnu/rnu rats. Using an immunoperoxide method with monoclonal anti-rat T-cell antibody, no T cells were identified in spleen, mesenteric lymph node and Peyer's patches. These data support earlier studies that the nude rat lacks functional T cells. As the counts of connective tissue mast cells (CTMC), intestinal mast cells (IMC) and globule leucocytes (GL) in small intestine of uninfected rnu/rnu rats were equal or higher than in +/rnu rats, it is concluded that the origin of these cells is thymus-independent. In contrast to +/rnu rats, infection of rnu/rnu rats induced no increase of CTMC, IMC or GL. Thus, these cells depend on T cells to undergo proliferation. Finally, results of this study were inconclusive whether IMC are precursors for GL, or that they represent independent cell populations.

Enhanced Antigen-Specific Delayed-Type Hypersensitivity and Immunoglobulin G2b Responses after Oral Administration of ViableLactobacillus caseiYIT9029 in Wistar and Brown Norway Rats

“…Sections 2 to 3 m thick were stained with hematoxylineosin in accordance with standard procedures and microscopically examined. The microscopic analysis was based on histopathological indices as described elsewhere (12,35).…”

“…The same section was scored for the severity of the inflammatory reaction around the encysted larvae based on the distribution of different cell types in the infiltrate and the number of inflammatory cells (35). A score of 0 indicates no inflammation, a score of 1 indicates minimal inflammation, a score of 2 indicates slight inflammation, a score of 3 indicates moderate inflammation, and a score of 4 indicates marked inflammation.…”

Expulsion of Secondary Trichinella spiralis Infection in Rats Occurs Independently of Mucosal Mast Cell Release of Mast Cell Protease II

“…Mastocytosis in T. spiralis infection is T cell dependent (39,40). Because intestinal mastocytosis was not required for rapid expulsion, and knowing that IgG2c mediates rapid expulsion in rat pups and can be produced in a T cell-independent manner (41), we tested the requirement for T cells in rapid expulsion by challenging parenterally infected, T cell-deficient rats.…”

A Neoplasm of Globule Leukocytes in a Cat

“…17 Using athymic mice, research has shown that these intestinal mast cells are thymus-dependent. 1y, 26 Since proliferation of globule leukocytes has been demonstrated to be thymus-independent,18s20 intestinal mast cell origin seems unlikely. These and additional studies lend support to the earlier hypothesis that globule leukocytes represent a unique population of mesenchymal origin.…”