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This Article Full Text Full Text (PDF) All Versions of this Article: jimmunol.0900944v1 183/9/5816    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Google Scholar Articles by Blum, L. K. Articles by Appleton, J. A. PubMed PubMed Citation Articles by Blum, L. K. Articles by Appleton, J. A.

Expulsion of Secondary Trichinella spiralis Infection in Rats Occurs Independently of Mucosal Mast Cell Release of Mast Cell Protease II¹

Lisa K. Blum,^2* Seana M. Thrasher,² Lucille F. Gagliardo,^* Valeria Fabre,^* and Judith A. Appleton^3*

^*James A. Baker Institute for Animal Health, Cornell University, Ithaca, NY 14853; and Abbotsford Veterinary Clinic, Abbotsford, British Columbia, Canada

Our aim was to elucidate the contribution of mucosal mast cells to the effector phase of a secondary immune response to Trichinella spiralis. During secondary infection, rats expel 90–99% of T. spiralis first-stage larvae from the intestine in a matter of hours. This phenomenon appears to be unique to rats and has been called rapid expulsion. Primary intestinal infection by T. spiralis induces mastocytosis, and mast cell degranulation occurs when challenged rats exhibit rapid expulsion. These observations have engendered the view that mast cells mediate rapid expulsion. In this study, we report that_. immunization of adult Albino Oxford rats by an infection limited to the muscle phase did not induce intestinal mastocytosis, yet such rats exhibited rapid expulsion when challenged orally. Although mastocytosis was absent, the protease unique to mucosal mast cells, rat mast cell protease II (RMCPII), was detected in sera at the time of expulsion. We further evaluated mast cell activity in neonatal rats that display rapid expulsion. Pups born to infected dams displayed rapid expulsion, and RMCPII was detected in their sera. By feeding pups parasite-specific mAbs or polyclonal Abs before challenge infection, it was possible to dissociate mast cell degranulation from parasite expulsion. These results indicate that rapid expulsion can occur in the absence of either intestinal mastocytosis or RMCPII release. Furthermore, release of RMCPII is not sufficient to cause expulsion. The data argue against a role for mast cells in the mechanism underlying the effector phase of protective immunity against T. spiralis in rats.

The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

¹ This work was supported by National Institutes of Health Grant AI 14490; S.M.T. was supported by T32 RR0759; and L.K.B. was supported by NBTC BDA-14.

² L.K.B. and S.M.T. contributed equally.

³ Address correspondence and reprint requests to Dr. Judith A. Appleton, James A. Baker Institute for Animal Health, 1 Hungerford Hill Road, Cornell University, Ithaca, NY 14853. E-mail address: jaa2{at}cornell.edu

⁴ Abbreviations used in this paper: mMCP-1, mast cell protease-1; AO, Albino Oxford; L₁, first-stage larvae; NBL, newborn larvae; RMCPII, rat mast cell protease II.