To assess the potential role of IgA antibody in expulsion of the nematode of the genus Trichinella from the intestine, a panel of IgA monoclonal antibodies (mAbs) were produced from the mesenteric lymph node cells from BALB/c mice orally vaccinated with irradiated muscle larvae of Trichinella britovi. One IgA mAb, HUSM-Tb1, formed immunoprecipitates on the surface of live muscle larvae, and by immunohistochemistry reacted with their stichocytes and cuticular surface, but not with those tissues of the adult stage or newborn larvae. Intraperitoneal injection of BALB/c mice with this mAb 5 h before challenge conferred a high level of protection (more than 95%) against T. britovi infection, when 2.0 mg of specific IgA/20 g body weight was given to a mouse. The same treatment produced a similar effect in SCID mice lacking functional T- and B-cells, indicating no requirement of synergistc T-cell factors for the effect. Passive transfer of the mAb at the time of challenge or later showed less or no effect upon worm expulsion. It is concluded that the mucosal IgA response, when adequately induced, can impede the establishment of infective Trichinella parasites in the mouse intestine.

EF-Tu delivers aminoacyl-tRNAs to ribosomes in the translation system. However, unusual truncations found in some animal mitochondrial tRNAs seem to prevent recognition by a canonical EF-Tu. We showed previously that the chromadorean nematode has two distinct EF-Tus, one of which (EF-Tu1) binds only to T-armless aminoacyl-tRNAs and the other (EF-Tu2) binds to D-armless Ser-tRNAs. Neither of the EF-Tus can bind to canonical cloverleaf tRNAs. In this study, by analyzing the translation system of enoplean nematode Trichinella species, we address how EF-Tus and tRNAs have evolved from the canonical structures toward those of the chromadorean translation system. Trichinella mitochondria possess three types of tRNAs: cloverleaf tRNAs, which do not exist in chromadorean nematode mitochondria; T-armless tRNAs; and D-armless tRNAs. We found two mitochondrial EF-Tu species, EF-Tu1 and EF-Tu2, in Trichinella britovi. T.britovi EF-Tu2 could bind to only D-armless Ser-tRNA, as Caenorhabditis elegans EF-Tu2 does. In contrast to the case of C.elegans EF-Tu1, however, T.britovi EF-Tu1 bound to all three types of tRNA present in Trichinella mitochondria. These results suggest that Trichinella mitochondrial translation system, and particularly the tRNA-binding specificity of EF-Tu1, could be an intermediate state between the canonical system and the chromadorean nematode mitochondrial system.

ABSTRACT. In the winter of 1997-1998, we collected parasitological data from 60 wild carnivora in the north-western part of Tohoku region, Japan. These included 7 foxes (Vulpes vulpes japonica), 20 raccoon dogs (Nyctereutes procyonoides viverrinus), 29 martens (Martes melampus melampus), 3 weasels (two Mustela sibirica itatsi and one M. nivalis namiyei), and one Japanese badger (Meles meles anakuma). Roundworms (Toxocara canis in foxes and Toxocara tanuki in raccoon dogs), hookworms (Ancylostoma kusimaense and Arthrostoma miyazakiense) and Molineus sp. in the small intestine were the most prevalent in foxes and raccoon dogs. In martens, Aonchotheca putorii in the stomach, Concinnum ten in the pancreatic duct, Molineus sp. and Euryhelmis costaricensis in the small intestine were the most prevalent. Collected parasites include some new helminth species for this region or Japan; the strobilar stage of Taenia polyacantha from foxes, Pygidiopsis summa from a raccoon dog, Eucoleus aerophilus, A. putorii, and Soboliphyme baturini from martens.

Non-pathogenic trypanosomes of the subgenus Herpetosoma are normally host specific, and laboratory models include Trypanosoma lewisi in rats and Trypanosoma musculi in mice. Two isolates of Trypanosoma grosi, originating from Apodemus agrarius and Apodemus peninsulae, grew well in Mongolian jirds, Meriones unguiculatus, after intraperitoneal inoculation of 2 x 10(5) or a minimum 500 bloodstream forms. The course of T. grosi infection in jirds resembled T. musculi infection in mice, rather than T. lewisi infection in rats. At week 2 to 3 p.i. trypanosomes disappeared from the bloodstream, and neither prednisolone treatment nor splenectomy prevented parasite elimination from the bloodstream. However, these treatments induced a marked increase in peak parasite counts. Regardless of prednisolone treatment or splenectomy, all jirds after day 21 p.i. became resistant to the reinfection. Although no trypanosomes were detected in the bloodstream of recovered jirds, dividing parasites persisted in the medullary capillaries of the kidney, like T. musculi infection in mice. We propose the T. grosi infection in jirds as an additional laboratory model for the study of non-pathogenic trypanosomes.

ABSTRACT. In the winter of 1998-1999, we collected parasitological data from 54 wild carnivores in the north-western part of Tohoku region, Japan. These consisted of 38 martens (Martes melampus melampus), 14 raccoon dogs (Nyctereutes procyonoides viverrinus) and 2 foxes (Vulpes vulpes japonica). Collected helminth parasites were 11 nematode, 10 trematode, 3 cestode, and a single acanthocephalan species, including 5 hitherto unknown species for this research area or the mainland of Japan (Honshu). Mesocestoides paucitesticulus was for the first time recorded from martens as well as from carnivores distributed in Honshu. Brachylaima tokudai originally recorded from Urotrichus talpoides in the central part of Honshu was for the first time found from a raccoon dog.-KEY WORDS: helminth, Martes melampus, Nyctereutes procyonoides.

Using histochemical ATPase-staining of the guinea pig epidermal sheet, we have demonstrated remarkable accumulations of ATPase-positive cells after exposure to attenuated Schistosoma mansoni cercariae. To characterize further the cells accumulating in the skin after exposure to S. mansoni, we produced a panel of monoclonal antibodies (MAb) to guinea pig leukocytes. These were immunohistochemically classified into 15 types and included MAb to the major histocompatibility complex (MHC) Class I and Class II molecules, shared antigens of all lymph node cells or between lymph node cells and Langerhans' cells (LC), T cells and macrophages (M phi), and M phi including the large Tingible body M phi in the secondary follicle. Varied MAb to M phi, including commercially available MAb (MR-1), were negative with ATPase- and MHC Class II-positive cells accumulated in the skin exposed to S. mansoni. Three MAb (HUSM-30 and 46, and commercially available MSgp2) detected an identical staining profile of accumulated cells with epidermal LC, but two MAb (HUSM-12 and 42) positively stained accumulated cells but not resident LC. These results indicate that the cells accumulated in the guinea pig skin within a few days after exposure to attenuated cercariae of S. mansoni are closest to LC, not to Mø, and may be blood-borne LC/dendritic cells.

Balamuthia mandrillaris is a free-living amoeba that lives in soil and water near human settlements. B. mandrillaris was first isolated from a mandrill baboon that died at the San Diego Zoo Wildlife Park in California in 1986, and the first human infection was reported in 1990. Although reported B. mandrillaris infections are often not properly characterized, it appears that B. mandrillaris invades the living body from the soil and water, either via a wound or the nasal cavity. Most confirmed infections have originated in South and North America. B. mandrillaris inhabits warm climates and is recognized as a pathogen in warm areas such as desert climates and tropical climates. B. mandrillaris has been isolated from environmental samples since 2000, most of which originated from warm areas such as step climates, tropical climates, and desert climates. However, B. mandrillaris may survive in diverse environments, although fewer granulomatous amebic encephalitis patients have been reported in colder Japanese and Northern European regions. In the present study, we conducted a survey of 13 soil samples in Aomori Prefecture located at the northernmost tip of Japan Honshu and successfully isolated one strain of B. mandrillaris from soil for the first time in Japan. In addition, B. mandrillaris gene was detected from several soils. This confirms that B. mandrillaris is capable of spreading to a wider climatic region.

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