Academic literature on the topic 'Small intestine in vitro larval rejection'

Changes in small intestinal motility reflective of local anaphylaxis are hypothesized to be associated with the rapid, immune-mediated rejection of infective larvae of the nematode Trichinella spiralis. This hypothesis was tested by comparing intestinal myoelectric activity in primarily and secondarily infected rats; the latter group represented immunized hosts, i.e., immunized by initial contact with the parasite. Patterns of slow waves, action potentials, interdigestive migrating myoelectric complexes, and migrating action-potential complexes induced by secondary infection differed from those associated with primary infection. Patterns in both cases differed from those in uninfected rats. Secondary but not primary infection evoked changes in myoelectric patterns within 15 min after administration of infective larvae. These changes could not be elicited by inoculation with dead larvae, larval excretory-secretory antigens, or a heterologous parasite, Eimeria nieschulzi. Results indicate that altered smooth muscle contractile activity is part of an anamnestic, stimulus-specific response to T. spiralis in immunized rats. These changes may represent the in vivo equivalent of the anaphylactically mediated intestinal smooth muscle contraction elicited in vitro in the Schultz-Dale reaction.

The normal tissue migration of Ascaris suum in the pig host involves larval development in the liver accompanied by considerable pathological changes. The vast majority of larvae that reach the small intestine are later expelled by unknown mechanisms. We show that when migration through the liver is bypassed by inoculation of pigs with an intravenous dose of larvae hatched in vitro, the larvae not only complete migration and return to the small intestine, but they also seem to have a greater chance of survival to adulthood. This technique offers new possibilities for studies on specific lung involvement in protective immunity, provides valuable information for the understanding of self cure by larval expulsion, and adds to our understanding of the evolution of migration of Ascaris larvae in tissues.

Abstract Introduction: Allogeneic hematopoietic cell transplantation (HCT) is increasingly utilized in the treatment of hematologic malignant and non-malignant diseases. Therapy-related toxicity and graft versus host disease (GVHD) remain major challenges as they significantly contribute to treatment related morbidity and mortality. Prolyl hydroxylase inhibitors (PHI) interfere with signaling cascades of inflammation and cell death. Their beneficial use in experimental models of ulcerative colitis and lung allograft rejection resulted in the hypothesis, that use of the PHI dimethyl oxalyl glycine (DMOG) reduces GVHD after murine allogeneic HCT. We already showed that DMOG treatment of allogeneic recipients resulted in significantly improved survival by day +50 compared to allogeneic controls, and was associated with significant decrease in organ pathology and proinflammatory cytokines (data not shown). We now expanded our study to better understand the underlying mechanisms for this observation. Methods: Acute GVHD was induced in lethally irradiated BALB/c mice followed by the infusion of 5 million bone marrow cells mixed with 4 million splenocytes from allogeneic C57BL/6 donors. DMOG dissolved in PBS was given at 8mg per mice intraperitoneally while controls received PBS only. Animals were monitored for clinical GVHD and survival and analyzed at day +7 and at day +50 post HCT. Formalin-fixed paraffin sections were processed for immunohistochemistry with CD3, Hif-1 alpha, or FADD pSer191 antibodies. Western blot analysis was performed after CD3/CD28 antibody activation of T cells to see the effect of DMOG treatment on Hif-1 α expression. Effect of DMOG on apoptosis and CD137 expression was analyzed by flow cytometry. Results: Our results demonstrate that the protective effect of DMOG is mainly caused by two independent pathways of apoptosis. DMOG treatment of allogeneic recipients resulted in decreased T cells infiltration (p=0.0534) and (Fas associated death domain) FADDpSer191 level (p<0.05) in small intestine sections at day +50. Decreased FADD pSer191 indicates decreased TNF-a induced epithelial cell apoptosis. This was associated with increased Hif1- α expression at day+7 (p<0.05) as well day+50 (p<0.05) as shown by histochemical analysis of small intestine sections. DMOG treatment of activated T cells showed increased expression of CD137 (p<0.005) and Annexin V FITC (p<0.005) staining suggesting that DMOG subjects T cells to activation induced cell death (AICD) via induced CD137 expression. Microscopic scanning of DMOG treated T cells showed condensed chromatin along with numerous fragmented nuclei, indicative of apoptotic cell. In vitro proliferative T cell responses were suppressed (p<0.05) in the presence of DMOG in a dose-dependent manner along with increase in Hif1- α level (p<0.05) as analyzed by western blot. Conclusion: Our data demonstrates protective effects of DMOG on the GI tract early after allogeneic HCT which is associated with improved survival and reduced lung injury at later time point. DMOG treatment results in the induction of CD137 on T cells subjecting them to AICD and represses FADD level in epithelial cells regulating their apoptosis. Taken together, DMOG treatment reduces GVHD via a two pronged mechanism, possibly allowing for novel strategies to prevent and treat this deleterious disease. Disclosures Palaniyandi: Pharmacyclics: Research Funding; Takeda Pharmaceutical International, Inc.: Research Funding; JAZZ: Research Funding.

The series of experiments described in this thesis were designed to investigate the role of suckling or late weaning in the response of young lambs to nematode infection. All experiments were conducted outdoors with grazing animals and no supplementation but for suckled groups of lambs whose counterparts were weaned to ryegrass – white clover swards. The parasite of interest was mainly Teladorsagia circumcincta solely but with mixed infection of Trichostrongylus colubriformis in one instance. In Chapter 3 (first experiment), the hypothesis that milk per se may have a direct effect on nematode development, rather than an indirect effect through enhancement of host immunity by superior nutrient supply was tested. Sixty, twinborn lambs were used, allocated to one of eight groups formed by either dosing lambs from 42 days of age or not with the equivalent of 1000 or 250 L₃ T. circumcincta larvae d⁻¹ until five days before necropsy, while a twin was either weaned at 39 days of age, suckled as single or twin until necropsy on day 84. The possibility that weaning one of a twin set onto pasture in close proximity to the ewe would cause abnormal ewe and lamb behaviour was tested by replicating the work in twins maintained as twins but in which one twin received equivalent of 250 and the other 1000 L₃ T. circumcincta larvae d⁻¹. This showed no abnormal ewe nursing or lamb suckling behaviour as a result of weaning a twin in a set. Relatively low faecal egg counts (FEC) and a two to three fold lower worm burdens suggest suckling could reduce larval establishment. Inability to detect peripheral titres of immunoglobulins supports this conclusion. An intra worm-population regulation of T. circumcincta, indicated by a pattern of greater egg-laying by a numerically smaller but physiologically better developed nematode population in suckled lambs measured in eggs 'in utero' and worm length made interpretation of FEC difficult. Suckling significantly improved weight gain and carcass weights, but early weaning did not reduce resilience to infection. In Chapter 4 (second experiment), 40 pairs of twin lambs, average age of 39 days, were either infected with the equivalent of 1000 L₃ T. circumcincta larvae d⁻¹ or not, while one twin was weaned and the other allowed to continue suckling. Necropsy was carried out on groups of five and six lambs from each of the uninfected and infected treatments, respectively, at mean age of 84, 112, and on six lambs from each group at 140 days of age. This serial slaughter allowed further confirmation of the hypothesis in Chapter 3 but also investigated the long-term effect of suckling on resistance or resilience of lambs at the trial when immune responses were anticipated to be developing. An in vitro direct larval challenge (IVDC) study, to monitor larval establishment, was carried out on tissue explants from necropsied lambs. Suckled lambs consistently showed lower FEC (P < 0.05) and worm burdens (P < 0.05) at every phase of the trial. Within the infected groups, % in vitro larval rejection suggested earlier immune responses in the weaned lambs by day 84, which was not consistent with lower worm burdens in suckled lambs but appeared similar in the subsequent necropsies. Lambs continued to show better growth due to suckling while weaning did not reduce the resilience of lambs confirming observations in Chapter 3. The immunoglobulin profile suggested the commencement of immune responses in lambs from the period after the 84th day necropsy, with significantly greater (P < 0.01) IgA titre in the infected groups, and the suckled lambs towards the end of the trial on day 140. A vaccinating effect of early exposure to parasites was coincidentally revealed as a result of unintentional pasture larval contamination, seen in suckled non-infected lambs shedding fewer eggs and harbouring fewer worms during the later necropsies compared with their weaned non-infected counterparts. In Chapter 5 (third trial), 93 pairs of twin lambs, 47 pairs of which received a vaccinating mixed infection of T. circumcincta and T. colubriformis larvae (60 L₃ / kg W / d) at ratio 40:60, respectively during the period 36 – 103 days of age, were either weaned early on day 51 or later on day 108. All lambs were drenched on day 108 and groups received challenge infections from day 116, at same rate with the vaccinating infection, or not, which ceased five days before respective necropsies. Necropsies were carried out on selected lambs on days 108, 184 and 218. The direct effect of milk on larval establishment appeared to feature only in the T. circumcincta populations on slaughter day 108. The long-term benefit of late weaning for development of resistance was conditional on lambs receiving the vaccinating infection, and appeared to be more pronounced in the small intestine, reflected by a greater reduction of T. colubriformis populations in that organ than of T. circumcincta populations in the abomasum. A negative consequence of enhanced immune response was the suggestion of an increased metabolic cost in reduced performance of lambs. In conclusion, the work provides support to the hypotheses that: (a.) suckling may reduce the establishment of nematode larvae through the direct effect of milk, (b.) may enhance rapid development of host immunity to infection, and (c.) it further suggests that lack of larval experience during suckling may have long term negative implications for host resistance. Finally, it suggests that milk may play little role in the enhancement of host resilience to infection and, on the contrary, that additional metabolic cost may be associated with a more rapid development of immunity resulting from larval challenge while suckling.

The term ‘anisakiosis (anisakidosis)’ or ‘anisakiasis’ collectively defines human infections caused by larval anisakids belonging to the nematode family Anisakidae or Raphidascarididae. Anisakis simplex, Anisakis physeteris, and Pseudoteranova decipiens are the three major species causing human anisakiosis. Various kinds of marine fish and cephalopods serve as the second intermediate hosts and the infection source. Ingestion of viable anisakid larvae in the fillet or viscera of these hosts is the primary cause of infection. The parasite does not develop further in humans as they are an accidental host. Clinical anisakiosis develops after the penetration of anisakid larvae into the mucosal wall of the alimentary tract, most frequently the stomach and the small intestine. The affected sites undergo erosion, ulceration, swelling, inflammation, and granuloma formation around the worm. The patients may suffer from acute abdominal pain, indigestion, nausea, vomiting, and in some instances, allergic hypersensitive reactions. Symptoms in gastric anisakiosis often resemble those seen in peptic ulcer or gastric cancer, and symptoms in intestinal anisakiosis resemble those of appendicitis or peritonitis. Treatments include removal of larval worms using a gastroendoscopic clipper or surgical resection of the mucosal tissue surrounding the worm. No confirmed effective anthelmintic drug has been introduced, though albendazole and ivermectin have been tried in vivo and in vitro. Prevention of human anisakiosis can be achieved by careful examination of fish fillet followed by removal of the worms in the restaurant or household kitchen. Immediate freezing of fish and cephalopods just after catching them on fishing boats was reported helpful for prevention of anisakiosis. It is noteworthy that anisakiosis is often associated with strong allergic and hypersensitivity reactions, with symptoms ranging from isolated angioedema to urticaria and life threatening anaphylactic shock.