I. Effect of Trichinella spiralis infection on the migration of mesenteric lymphoblasts and mesenteric T lymphoblasts in syngeneic mice.

The migration of [125I]UdR-labelled mesenteric lymph node cells in NIH strain mice at various times after inis produced an enhanced accumulation of mesenteric immunoblasts in the small intestine at 2 and 4 days after infection but not at later times. The enhanced migration occurred when using cells from both uninfected and infected donors, denoting an absence of antigenic specificity. This effect is not secondary to a reduced arrival of cells at sites away from the gut in infected mice, but to a primary increase of the arrival in the small intestine. Mesenteric T lymphoblasts (separated on a nylon-wool column) migrated to the small intestine of uninfected recipients and appear to be a major portion of the population which migrate to the gut of infected recipients. Our results were confirmed using 51Cr to label mesenteric cells. We conclude that the parasite causes the small intestine to become more attractive or retentive for mesenteric blast cells early during infection.     

Regional blood flow and the localization of lymphoblasts in the small intestine of the mouse. I. Examination of normal small intestine.

The localization of 125I-UdR-labelled mesenteric lymphoblasts and the fraction of the cardiac output delivered to the small intestine was investigated in mice. When different regions of the small intestine were examined, the proportional delivery of the cardiac output and the localization of lymphoblasts were found to vary along the length of the small intestine. A significant correlation between these two phenomena was identified when both lymphoblast localization and the distribution of the cardiac output within the small intestine were studied concurrently. The intestinal localization of populations of unseparated or T-enriched mesenteric lymphoblasts and peripheral lymphoblasts all showed a similar degree of correlation with the fraction of the cardiac output delivered along the small intestine in spite of marked differences in their proclivity to accumulate in the gut. We conclude that there is an important relationship in normal animals between the level of lymphoblast accumulation within a particular region of the small intestine and the delivery of blood-borne cells to that region. This relationship could provide a physiological explanation for a antigen-independent yet non-uniform distribution of effector cells within the lamina propria of unimmunized animals.     

Regional blood flow and the localization of lymphoblasts in the small intestine of the mouse. II. The effects of a primary enteric infection with Trichinella spiralis.

The localization of 125I-UdR-labelled mesenteric lymph node cells in the small intestine and the fraction of the cardiac output delivered to this organ in mice has been examined. Concurrent measurements of these two phenomena in normal animals showed that there was a significant correlation between the localization of lymphoblasts and the distribution of regional blood flow along the small intestine. In mice undergoing enteric infection with Trichinella spiralis, however, the nature of the connection between lymphoblast localization and blood flow distribution in the small intestine was altered. More lymphoblast label accumulated in the small intestine of infected mice than in uninfected animals even at stages of the infection when no alteration in the proportion of the cardiac output received by the small intestine had occurred. Enhanced lymphoblast accumulation occurred in different segments of the infected small intestine as the infection proceeded and these changes paralleled the way in which the parasite burden was distributed in the intestine. The kinetics of lymphoblast accumulation in infected and uninfected small intestine was examined under circumstances where the delivery of blood-borne labelled cells was the same. This showed that both increased entry of lymphoblasts and enhanced retention of lymphoblasts occurred in the parasitized small intestine.     

Genetic control of immunity to Trichinella spiralis. Donor bone marrow cells determine responses to infection in mouse radiation chimaeras.

Radiation chimaeras, prepared from NIH (rapid-responder) mice or from the F1 progeny of a cross between H-2 compatible B10.G (slow-responder) and NIH mice, were tested for their ability to respond to infection with the intestinal nematode parasite Trichinella spiralis. Mice reconstituted with bone marrow (BM) from NIH donors showed the rapid response characteristic of this strain, i.e. expelled worms from the intestine before day 12 of infection; those given BM from B10.G mice showed a show expulsion pattern, losing worms after day 12. There was no evidence that the environment of the recipient exerted any influence on the ability of the BM cells to express the response characteristic of the donor. When chimaeras were given immune mesenteric lymph node cells (IMLNC) from infected NIH donors there was successful adoptive transfer of immunity, resulting in an accelerated loss of worms. As before, the time course of the accelerated response was determined by the genotype of the BM used. These results confirm that genetic control of the process of worm expulsion is expressed at the level of a bone marrow-derived cell population and is independent of lymphocyte responsiveness. They further show that the factors involved are an inherent property of the cells concerned. The possibility that these cells are myeloid in nature is discussed.     

Selective localization of mesenteric lymphoblasts in mucosal tissues: effects of altering the number of donor lymphoblasts.

We have studied the effect of altering the numbers of lymphoblasts from the mesenteric lymph node (MLN) transferred into syngeneic female CBA/J mice on their distribution and abundance 24 hr later. The frequency of [3H]-thymidine-labelled donor MLN cells in the recipient small intestine and lungs was directly related to the numbers transferred. Of the donor MLN lymphoblasts in the small intestine, 62.5% +/- 0.9% were seen in the basal lamina propria, 32.5% +/- 0.9% in the villus lamina propria and 5% +/- 0.6% in the epithelium. Of the MLN lymphoblasts localizing in the lungs, 90% +/- 2.3% were in the parenchyma while 6.7% +/- 1.8% and 3.3% +/- 1.0% appeared in the bronchus-associated lymphoid tissue (BALT) and the bronchial epithelium, respectively. Although few peripheral lymph node (PLN)- derived lymphoblasts localized in the small intestine, the numbers of PLN lymphoblasts in the lungs were similar to those observed after transfer of comparable doses of MLN lymphoblasts. However, PLN Lymphoblasts were found only in the pulmonary parenchyma and did not appear in either BALT or bronchial epithelium. These data suggest that the number of MLN, but likely not PLN, lymphoblasts in the circulation, directly influences the numbers of lymphoblasts which localize in intestinal mucosa, BAlt and bronchial epithelium. Even at the highest doses of MLN lymphoblasts transferred we could not saturate the capacity of these tissues to accommodate MLN lymphoblasts nor was their intra-intestinal distribution altered.     

The in-vivo kinetics of lymphoblast localization in the small intestine.

We have studied the in-vivo kinetics of the accumulation of 125I-UdR labelled mesenteric lymphoblasts in the small intestine of mice. The efficiency with which the labelled cells were extracted from the blood and retained by the intestine was quantified by examination of the accumulations observed over the first 4 hr after cell transfer. The kinetic parameters for the uptake and retention of lymphoblasts determined from these early times were found to provide a good approximation to the entire time course of accumulation observed from 1 hr to 22 hr after cell transfer. For normal mice, approximately 1% of lymphoblasts delivered by the blood stream at any given time gained entry to the small intestine and were retained with an average half-time of 6.5 hr. We also studied the accumulation of lymphoblasts in the small intestine of mice undergoing a self-limited enteric infection with the nematode, Trichinella spiralis. There was a greater accumulation of lymphoblasts in the small intestine of these animals. This was the consequence of a prolongation of the half-time for retention of lymphoblasts within the intestine to 15 hr, rather than increased uptake of lymphoblasts from the blood. During a secondary infection with T. spiralis, the half-time for retention of lymphoblasts in the intestine was decreased to 3 hr. These studies show that viewing the accumulation of lymphoblasts as the result of a series of first order kinetic processes provides a suitable model for the migration of lymphoblasts to the small intestine.     

Genetic control of immunity to Trichinella spiralis in mice: capacity of cells from slow responder mice to transfer immunity in syngeneic and F1 hybrid recipients.

Mice of the C57BL/10 (B10) strain are slow responders to infection with T. spiralis in terms of ability to expel worms from the intestine. Compared with rapid-responder NIH mice, infection stimulates a slower and reduced blast cell response in the draining mesenteric lymph node (MLN). Transfer of immune cells from the MLN (MLNC) does not accelerate worm expulsion from naive B10 recipient mice, even though MLNC from this strain effectively transfer immunity to (B10 X NIH) F1 recipients. In common with other B10 background mice C57BL/10 show an infection-dose related suppression of immunity to T. spiralis. Such suppression does not appear to determine the response to MLNC, as adoptive transfer into B10 recipients was not enhanced by reducing the level of challenge infection given, and transfer into F1 recipients was unaffected by simultaneous transfer of lymphocyte populations from donors infected at a level which would induce suppression. A hypothesis is proposed which relates slow response status to (i) the inherent capacity of the intestinal inflammatory component of worm expulsion, and (ii) the outcome of infection-dose related stimulatory and suppressive influences acting on the two interacting lymphocyte components of expulsion. The relevance of H-2-linked and non-H-2 genes to the control of the response is discussed.     

Parasite and vertebrate host genetic heterogeneity determine the outcome of infection by Schistosoma mansoni

Intraspecific variation in Schistosoma mansoni infection and modulation of its expression by vertebrate host genetics was studied by evaluation of some biological parameters of the infection in BALB/c and C57BL/6 mice infected with one Brazilian (BH) and two Venezuelan (YT and SM) laboratory strains of the parasite. Mice infected with 60 cercariae of each parasite strain were euthanized at 5, 6, 8, and 12 weeks. Parameters recorded included the number of adult worms recovered by portal perfusion (infectivity); the number of eggs in the feces, the intestine, and the liver; and the ability of the eggs to cross the intestine, expressed as a quotient of the number of eggs in the intestine versus the feces. Results showed that the parasite appeared to determine the infectivity, the sex ratio, the onset and timing of oviposition, the number of eggs produced, initial egg laying toward the liver, and the ability to cross the intestinal wall. In this sense the BH strain appeared to be the most efficient and the SM strain, the most delayed; the YT strain was intermediate, although closer to the SM strain. On the other hand, the host appeared to influence the susceptibility to infection, the fecundity, and the percentage of eggs distributed in the liver and in the intestine during the chronic stage. In this sense, although they have been shown to be less susceptible to infection than BALB/c mice, C57BL/6 mice permit more eggs to be produced and exhibit similar numbers of eggs in the intestine and the liver at certain time points. It appears from these results that parasite genetics is essential for the outcome of infection with S. mansoni, but some characteristics may be quantitatively modulated by host genetics. Received: 13 March 2000 / Accepted: 3 July 2000     

Murine filariasis: interleukin 4 and interleukin 5 lead to containment of different worm developmental stages

We compared the impact of IL-4 and IL-5 deficiency during the fully permissive infection of BALB/c mice with the rodent filaria Litomosoides sigmodontis. IL-5, in contrast to IL-4, is crucial for the containment of adult worms during short- and long-term infections. IL-5 KO mice allowed development of more larvae into adult worms and showed up to 200 times more adult worms persisting during chronic infection (day 60 until 200 post-infection). This increased persistence was accompanied by a reduction in inflammatory nodules around adult filariae. In contrast, adult worm survival and nodule formation did not differ between BALB/c wild-type mice and BALB/c IL-4 KO or BALB/c IL-4 receptor (IL-4R) alpha-chain KO mice. In both IL-4 and IL-5 KO mice microfilaraemia was greatly enhanced (160-fold) and prolonged compared to wild-type mice. This extent of susceptibility to microfilariae required the presence of adult worms in a full infection cycle since upon intraperitoneal injection of microfilariae alone they were removed from BALB/c, BALB/c IL-4 KO and BALB/c IL-4R alpha-chain KO mice with equivalent kinetics, and since microfilarial survival was only slightly increased in IL-5 KO mice (factor of 5 vs. factor of 160 in full infection). In conclusion, IL-4 and IL-5 dependent effector pathways operate against different stages of filarial worms, and IL-5 has a greater impact on parasite containment than IL-4.     

Platelet-activating factor receptor deficiency delays elimination of adult worms but reduces fecundity in Strongyloides venezuelensis-infected mice

We describe the parasitological kinetics and histopathological and immunological alterations in platelet-activating factor receptor-deficient (PAFR(-/-)) and wild-type mice after a single Strongyloides venezuelensis infection (subcutaneous inoculation of 500 L3 larvae). There was no difference in the numbers of worms that reached and became established in the small intestines of PAFR(-/-) and wild-type mice. However, at 12 days after infection, significantly more worms were recovered from PAFR(-/-) mice. Although PAFR(-/-) infected mice showed a delay in elimination of adult worms, worms established in the small intestine of these mice produced a significantly lower number of eggs due to a reduction in worm fecundity. There were also significant reductions in the number of circulating and tissue eosinophils and tumor necrosis factor levels in the small intestines of PAFR(-/-) mice infected for 7 days compared to the number and level in wild-type mice. Histological analysis confirmed the reduced inflammatory process and revealed that the PAFR(-/-) mice had a smaller number of goblet cells. The concentrations of the type 2 cytokines interleukin-4 (IL-4), IL-5, and IL-10 were lower in small intestine homogenates and in supernatants of antigen-stimulated lymphocytes from spleens or mesenteric lymph nodes of PAFR(-/-) mice than in the corresponding preparations from wild-type mice. Thus, in S. venezuelensis-infected PAFR(-/-) mice, decreased intestinal inflammation is associated with enhanced worm survival but decreased fecundity. We suggest that although a Th2-predominant inflammatory response decreases worm survival, the worm may use factors produced during this response to facilitate egg output and reproduction. PAFR-mediated responses appear to modulate these host-derived signals that are important for worm fecundity.     

A case of nonrotation of the midgut with a middle mesenteric artery.

In 2002, we came across a very rare case of nonrotation of the midgut with a middle mesenteric artery (MM) (tentative name). It was found in a 73-year-old Japanese female cadaver donated for student dissection at Kumamoto University. In this case, the small intestine occupied the right half of the abdominal cavity and the large intestine occupied the left half. The caecum was situated on the anterior inferior part of the abdominal cavity near the midline. The duodenum (Du) was fused to the posterior abdominal wall. The small intestine except the Du and the ascending colon were suspended from the posterior abdominal wall by the mesentery, but the remainder of the colon was fused to the left posterior abdominal wall. In addition, an anomalous branch arose from the abdominal aorta between the superior and inferior mesenteric arteries (SM and IM) in this case. It chiefly supplied the ascending and the transverse colons and anastomosed with the SM and IM, respectively, through the marginal arteries. It is very rare that these anomalies appear simultaneously in one body. In this case, it is difficult to declare that the existence of the MM directly caused the nonrotation of the midgut, but it is reasonable to suppose some kind of relation between them.     

Oral vaccination against coccidiosis: responses in strains of mice that differ in susceptibility to infection with Eimeria vermiformis.

Four strains of mice with different susceptibilities to Eimeria vermiformis were orally dosed with a crude antigen prepared from sporulated oocysts of the parasite, with or without cholera toxin as adjuvant. The effect on subsequent challenge infections depended on the resistance and susceptibility phenotypes of the host: oocyst production was reduced in susceptible C57BL/6 and NIH mice but increased in resistant BALB/c and C3H mice. Despite this contrast, no fundamental differences were detected between the immune responses of BALB/c and C57BL/6 mice, either to vaccination or after superimposed infection, but the suppressing and enhancing effects of vaccination were transmissible to naive recipients via suspensions of mesenteric lymph node cells. The results obtained are compared with those previously reported for parenterally immunized BALB/c and C57BL/6 mice.     

Observations on the distribution of an immune-adapted population of Nippostrongylus brasiliensis within the small intestine of rats given repeated small challenge infections

Summary A study was made, over a period of 12 weeks, of the distribution of a population of immune-adapted worms that had established themselves in the small intestine of rats as a result of exposure to a number of small daily challenge infections with the nematode Nippostrongylus brasiliensis.Immature adapted worms were found to inhabit a greater length of the small intestine than immature primary infection worms. Mature worms, however, were restricted to the anterior two-fifths of the small intestine, the great majority of these infesting the region of the duodenum. The worms were not expelled from the intestine by an acute host-reaction, a large proportion of the worms still being present on the eighth week after the last larval challenge.Evidence was obtained that these immune-adapted worms favoured the duodenal environment rather than the other regions of the intestine and that this attraction for the duodenum was not affected by the immune state of the host.     

Inflammatory response during the muscle phase of Trichinella spiralis and T. pseudospiralis infections

An attempt was undertaken to determine whether a concurrent infection of Trichinella spiralis and T. pseudospiralis can reduce cellular infiltrations against the former species during the muscle phase of worm development. BALB/c, nude and CBA/N mice were orally infected with either species or a mixture of both. New-born larvae (NBL) of either or both species were also injected subcutaneously into the right/left leg of BALB/c mice. In T. spiralis oral infection, myositis was strongest in BALB/c, intermediate in CBA/N and weakest in nude mice. In T. pseudospiralis oral infection, slight cellular infiltrations were observed around the worms in BALB/c but not in nude or CBA/N mice. However, in mixed oral infections of two species, infiltrations around the sites of T. spiralis were not reduced. In mice injected with T. pseudospiralis NBL, infiltrations around the infective-stage larvae were mostly absent. However, in mice injected with T. spiralis NBL, prominent granulomatous reactions were observed near the sites of worms. The tissue reaction was substantially stronger than that in oral infections. In mice injected with NBL of both species (into different legs), a heavy infiltration was also observed at the site of T. spiralis. A marked increase in levels of IL-4 and IL-6 was detected in the popliteal lymphocytes of BALB/c mice injected with either live or dead NBL of T. spiralis at days 15 and 20 post-injection. This indicated that the worms mainly elicited a TH2 response during the muscle phase of development. An indirect fluorescent antibody test and laser confocal microscopic studies demonstrated the presence of CD4 and CD8 cells in the cytoplasmic region of the nurse cell complex of T. spiralis.     

Induction and characterization of isogeneic anti-idiotypic antibodies to BALB/c myeloma S117: lack of reactivity with major idiotypic determinants.

Isogeneic anti-idiotypic antibodies were induced by immunization of BALB/c mice with the BALB/c-derived myeloma protein S117 which binds N-acetylglucosamine-containing antigens including Group A streptococcal carbohydrate (A-CHO). Most BALB/c mice produced anti-S 117 idiotypic antibodies, as shown by various different immunization protocols. The antibodies of individual mice were of intermediate to high affinity (2.8 x 10(6) M-1 to 1.4 x 10(8) M-1). In isoelectric focusing, most individual antibodies were shown to consist of a small number of clonotypes, but each mouse produced its own unique set of clones so that the potential clonal repertoire of strain BALB/c is rather large. Most importantly, all isogeneic anti-idiotypic antibodies were directed against idiotypic determinants of S117 that are not shared with induced anti-A-CHO antibodies, whereas it has been shown previously that allogeneic and xenogeneic anti-S 117 idiotypic antibodies react with idiotypic determinants unique to S 117 as well as with those that are shared with anti-A-CHO antibodies. The data suggest that the expression of S 117 idiotypic determinants in strain BALB/c is not under antibody-mediated, anti-idiotypic feedback control.     

Light and scanning electron microscopy ofEchinostoma caproni (Trematoda) during maturation in ICR mice

Light (LM) and scanning electron microscopy (SEM) were used to study the maturation ofEchinostoma caproni in 13 ICR mice, each of which was exposed to 50 encysted metacercariae and necropsied at 1–20 weeks postinfection (p.i.). All 13 mice were infected with 20–30 worms/host and half the worms were used for LM and the remainder, for SEM. Body area measurements showed that the worms grew rapidly from day zero (excysted metacercariae) to 4 weeks p.i. and less rapidly thereafter. Area measurements of organs showed that the growth of the acetabular area paralleled that of the body. Gonadal area growth was less rapid than acetabular growth, and the area of the posterior testis was always greater than that of the anterior testis. The most remarkable change in topography occurred by 5 weeks p.i. when some of the ventral tegumentary spines became multipointed with 2–5 points/spine. Spine division was associated with a decline in worm growth, but the significance of this finding is unclear. Spine division probably facilitates the feeding, abrasion, and migration of this echinostome in the mouse small intestine.     

Formation of lymph follicles and germinal centers in the somatic and mesenteric lymph nodes of growing mice during ontogenesis

We investigated the age-dependent changes that occur in the numbers of lymph follicles and germinal centers in various lymph nodes in BALB/C and ICR mice aged between four days and 16 to 18 weeks. Young adult BALB/C mice have a relatively small body size, compared to ICR mice at the same stage, where there is a relatively large body size. In BALB/C mice somatic (popliteal, brachial, axillary, inguinal, submandibular and deep cervical) and mesenteric lymph nodes were examined. In ICR mice only the somatic (popliteal, brachial and axillary) lymph nodes were examined. In both BALB/C and ICR mice, the primary follicles were apparent in most somatic nodes by the 6th postnatal day. Up to 28 days of age, the number of follicles per node increased, reaching different levels in nodes from different locations. Thereafter, in most of the somatic nodes in BALB/C mice the number of follicles increased only slightly, although there was a substantial increase in ICR mice, reaching a peak or a plateau at 8 or 12 weeks of age. In the mesenteric (ileocecal) nodes in BALB/C mice, the primary follicles first appeared at 10 to 12 days, then there was a linear increase until a plateau level was reached at 8 weeks of age. Germinal centers appeared in the mesenteric nodes at 28 days and increased rapidly in number thereafter. In most somatic nodes germinal centers were scarcely observable until 8 weeks of age. Based on our observations we have three suggestions. Firstly, in BALB/C mice there were two different patterns of age-dependent changes in the numbers of lymph follicles in the somatic and the mesenteric nodes during ontogenesis. These different patterns are probably due to variations in the magnitude of the exogenous antigen stimulatory effect. Secondly, it seems likely that the variations in the numbers of lymph follicles that are produced in somatic nodes at different locations during the first 28 days after birth relate to the dimensions of the body regions that are drained by that particular somatic node at that stage of development. Thirdly, in the relatively small BALB/C mice, the ontogenetic production of lymph follicles in a somatic node is mostly completed during the first four weeks of life, whereas in the relatively larger ICR mice, this process may continue until the young adult stage of 8 weeks.     

Immunological memory and lymphoblast-migration in mice infected withHymenolepis nana

The presence of small cells carrying memory and lymphoblast migration in C57 Bl/6N inbred mice with the intestinal parasiteHymenolepis nana were investigated.Hymenolepis nana egg-infection stimulated an enhanced accumulation of mesenteric lymphoblasts at days 3, 6 and 9 after infection; lymphoblasts accumulated selectively in the mesenteric nodes (MLN)_ of mice suggesting a cell-trapping effect. The migration was studied using lymphoblasts from non-infected donors. Spleen cells and MLNC collected from donor mice 30 days after a primary infection and enriched for T cells were able to transfer an adoptive immunity, by contrast unseparated cells were uneffective. This result provides preliminary evidence for the existence of T memory cells in the spleen and in the mesenteric nodes.     

Impaired intestinal localization of mesenteric lymphoblasts associated with vitamin A deficiency and protein-calorie malnutrition

We examined whether protein-calorie (PC) and vitamin A (VA) deficiencies altered the intestinal localization of mesenteric lymph node (MLN) lymphoblasts using an adoptive lymphocyte transfer method. MLN cells from donor rats were labelled in vitro with [125I]-deoxyuridine and injected i.v. into various recipients. Twenty-two to twenty-four hours after transfer of labelled cells prepared from PC-deficient donors, the percentage of radioactivity in the small intestine of normal recipients was two-thirds of that detected after transfer of cell obtained from normal donors. When donor cells were obtained from rats suffering both PC and VA malnourishment, this decrease was even greater, being only one-third of the normal donor cell control. Other experiments indicated that the defect in localization behaviour was associated with the donor blasts and not the recipient intestine. These findings suggest that defective localization in mucosal lymphoblasts may be a factor contributing to morbidity in malnourished populations.     

Pathogenicity and antigen detection of the Nouzilly strain of transmissible gastroenteritis coronavirus, in 1-week-old piglets.

We compared the pathogenicity and the sites of multiplication of the attenuated Nouzilly strain, with the highly passaged Purdue-115 and the virulent Gep II strains of transmissible gastroenteritis (TGE) coronavirus, in 1-week-old weaned piglets. The immunohistochemical peroxidase technique, with an antiviral nucleoprotein monoclonal antibody, was used for the localization of the multiplication sites, in the intestine and other organs. The Gep II and the Purdue-115 strains, administered orally to piglets, caused clinical signs and lesions of TGE. These strains multiplied within the intestinal tract in the enterocytes of the jejunum and ileum, Peyer's patches and mesenteric lymph nodes. In view of the small numbers of infected cells in the tonsils, spleen, kidney, liver and lung, these tissues are not considered to be preferential multiplication sites. The attenuated Nouzilly strain multiplies only in the ileum and the mesenteric lymph nodes. The variation in the tropism for particular parts of the intestine (with the preferential localization of the virus in the ileum rather than the jejunum), could be related to the high degree of attenuation of the Nouzilly strain.