A newly emerged focus of zoonotic cutaneous leishmaniasis in South-western Iran.

Leishmaniasis is rising in many countries, including Iran, due to climate change, refugee crises, urbanization and etc. The aim of this study was to explore the epidemiology, extent and identity of Leishmania species in a newly emerged focus in Abdanan County, Ilam Province, South-western Iran. This study was performed as a descriptive cross-sectional study by a systematic house-to-house approach. The Leishmania species was identified by RFLP-PCR and sequencing. Altogether, 46799 individuals consisting of 22907 (48.9) female and 23892 (51.1%) male were interviewed and physically examined for the presence of skin lesions. Overall, the incidence rate was 0.34% (n = 160). All age groups were affected and the incidence rate was the highest in <10 years of age group (0.49%) and the lowest in >50 years old individuals (0.15%), although there was no significant difference regarding the sex and age. The majority of patients had one lesion (47.5%) on hands (56%) and most of the cases occurred in Abdanan city (%54) in summer. Based on the RFLP-PCR analysis, all the Leishmania isolates were L. major of single genotype. A newly emerged focus of zoonotic CL caused by L. major occurred in South-western of Iran. Multiple risk factors created this epidemic area. Further studies on the vector and reservoir are crucial needed to provide evidences to select the prophylactic and therapeutic measures for future control strategies.

Properties of biological and biochemical effects of the Iranian saw-scaled viper (Echis carinatus) venom.

The venom of Echis carinatus is rich in proteins and peptides effective on the hemostatic system. This venom is contains metalloproteinase which convert prothrombin to meizothrombin. The prothrombin activator which leads to the formation of small blood clots inside the blood vessels throughout the body. To understand the mechanism of the effects of Iranian Echis carinatus venom, the effects of E. carinatus on human and Wistar rat plasma, plasma proteins (prothrombin and fibrinogen) and blood coagulation were studied. Proteolytic activity of the crude venom on blood coagulation factors such as prothrombin, partial thromboplastin and fibrinogen times were studied. In the present study the PT test for human plasma was reduced from 13.4 s (±0.59) to 8.6 s (±0.64) when human plasma was treated with crude venom (concentration of venom was 1 mg/ml) and for rat plasma PT was reduced from 14.5 s (±0.47) to 8 s (±0.49). Some possible biological and biochemical effects of IEc crude venom were investigated. The blood coagulation in human and in rat were investigated in vivo and in-vitro. In this paper, we show that the procoagulant action of Echis carinatus venom is due in part to a protein component that activates prothrombin and the procoagulant activity on human and rat plasma was evaluated (Tab. 2, Fig. 2, Ref. 31).

Similar neuronal alterations induced by axonal injury and learning in Aplysia.

Learning in the marine mollusk Aplysia has been associated with enhanced sensory function, expressed in mechanosensory neurons as (i) decreases in action potential threshold, accommodation, and afterhyperpolarization, and (ii) increases in action potential duration, afterdischarge, and synaptic transmission. These alterations also occur, with a delay, after sensory axons are injured under conditions in which synaptic transmission is severely reduced. The latency and specificity of injury-induced alterations indicate that induction signals are generated at the site of injury and conveyed centrally by axonal transport. Similarities in neuronal modifications support the hypothesis that some memory mechanisms evolved from mechanisms of injury-induced sensory compensation and repair.

Campylobacter jejuni and Campylobacter coli in cecum contents of chickens of slaughter age: A microbiological surveillance.

The presence of foodborne pathogens is a major concern for the food industry and increase in antibiotic resistance adds to the seriousness of this issue. Epidemiological studies have shown that there is little or no information from Iran on the prevalence of Campylobacter spp. in chickens of slaughter age. The aim of this study was to determine the prevalence, antibacterial susceptibility and type of Campylobacter species isolated from the cecum of chickens bred in Saqqez city, Kurdistan, western Iran. Campylobacter was isolated and identified by culture and molecular methods. Antibiotic susceptibility of Campylobacter species was performed by disk agar diffusion test and agar dilution methods. The bacterial isolates were typed by repetitive element sequence based polymerase chain reaction (rep-PCR) method. Fifty-five percent of the farms were found to be contaminated with Campylobacter spp. Gene amplification assay confirmed 67 isolates with Campylobacter spp., of which 57 (85.1%) were identified as C. jejuni and 10 (14.9%) as C. coli. Resistance to tetracycline was the most common finding (70.6%), followed by ciprofloxacin (63.7%) and amoxicillin (27.5%). All isolates retained their susceptibility towards gentamicin and meropenem. Results of MIC50 and MIC90 confirmed high resistance towards tetracycline and ciprofloxacin. Repetitive element sequence based-polymerase chain reaction (rep-PCR) placed C. jejuni in six profiles, while C. coli could not be separated as diverse clones. The present study focused on obtaining data regarding prevalence, antibiotic susceptibilities, genetic diversity at regular intervals and maintain and improve hygiene. The results of this study showed substantial genetic diversity of C. jejuni in chickens from western Iran.

Evaluation of the effects of chemical versus biological control on Botrytis cinerea agent of gray mould disease of strawberry.

This study investigates on effects of four fungicide and six isolate from Trichoderma and Gliocladium on Botrytis cinerea agent grey mold of strawberry under library and greenhouse condition. The effect of four fungicides i.e. benomyl, dichlofluanid, captan and triadimenol on B. cinerea was studied in the laboratory condition by method mixed poison to culture medium. It was shown that the fungicide including benomyl, triadimenol, dichlofluanid and captan were able to inhibit mycelial growth of B. cinerea on PDA plate with EC50 of 0.16, 1.42, 3.40 and 7.73 ppm respectively. These fungicides delayed myceliogenic germination of sclerotia at 1000 ppm, while exhibiting no fungicidal effect. Moreover, the antagonistic effects of six fungi including Trichoderma koningii (T21), T. viride (T4), T. harzionum (T5), T. viride (T2), G. virens (G2), G. virens (G8) on B. cinerea were assessed. This assessment was done under library condition and its results as follows: The antagonistic mechanism occurred through branching at the end of B. cinerea hyphae, hyphal contact, coiling, vacuolization and lyses. Volatile metabolites of T. koningii (T21) and non-volatile metabolites of G. virens (G2 and G8) and T. koningii (T21) caused maximum inhibition of the fungal growth. Trichoderma spp and G. virens were able to colonize and sporulate on sclerotia and caused their lysis within 7-21 days. In greenhouse, a completely randomized design with 11 treatments (4 chemical and 6 biological and one untreated control) each replicated five times were used for the comparison. Greenhouse studies revealed that application of fungicides i.e. captan, dichlofluanid, triadimenol and benomyl reduces disease severity by 42, 45, 48 and 52% respectively. The fungal antagonists reduce the grey mold disease severity between 5-42%. All treatments caused a decline in post harvest disease, as the most effective treatment of chemical control was benomyl with 68.33% and for the biological treatment this was T. koningii (T21) with 56%.

Radiofrequency and laser ablation of spinal lesions.

Radiofrequency current and laser energy can be delivered locally through electrode-needle or optical fiber inserted in the tissue and allows local ablation of tissues, up to a volume of 4 to 5 cm in diameter with one application or vaporizes tissue. Tumor ablation guided with medical imaging proved a high local efficacy over 90% for tumors less than 25 mm in the liver, lung, and kidney. The spinal applications of the thermal energy of RF and laser are reported in this paper. First, the tumor ablation is reviewed with malignant and benign tumors. In malignant tumors, radiofrequency is very efficient in local tumor control and in pain management. The second part of this paper is devoted to disk diseases where laser and RF techniques increase their applications. The technique, indications and results of these techniques are reported and illustrated.

Outcome of pregnancy in chronic myeloid leukaemia patients treated with tyrosine kinase inhibitors: short report from a single centre.

BACKGROUND: The aim of this work was to report on the outcome of pregnancy in patients with chronic myeloid leukaemia who were on tyrosine kinase inhibitor treatment. PATIENTS AND METHODS: We report the result of 22 pregnancies in 14 patients (9 female and 5 male) who conceived or their partner conceived while being on tyrosine kinase inhibitors for their CML. RESULTS: All pregnancies except one were uneventful. 25 newborns were born and except in one case where small atrial septal defect was diagnosed, all infants were healthy and showed normal development after birth. CONCLUSION: This small series does indicate that parents can most likely expect an uneventful outcome to a pregnancy despite exposure of either partner to TKIs. There is no consensus or guideline regarding the best practice in case of pregnancy. More reports of similar nature would certainly be beneficial to practitioners and patients alike. As such it is still recommended to practice effective contraception during the period of TKI treatment.

The pathogenesis of Acanthamoeba keratitis.

Free-living amoebae of the genus Acanthamoeba produce a progressive, blinding infection of the corneal surface. The pathogenesis of Acanthamoeba keratitis involves parasite-mediated cytolysis and phagocytosis of corneal epithelial cells and induction of programmed cell death. Acanthamoeba spp. elaborate a variety of proteases which may facilitate cytolysis of the corneal epithelium, invasion of the extracellular matrix, and dissolution of the corneal stromal matrix.

Characterization of a plasminogen activator produced by Acanthamoeba castellanii.

Serine proteases play an important role in a diverse array of biological processes, including embryogenesis, metastasis, angiogenesis, thrombolysis and tissue invasion by certain parasites. The latter observation prompted us to explore the possibility that the tissue-invasive ocular parasite Acanthamoeba castellanii elaborates one or more serine proteases. Acanthamoeba sp. are pathogenic free-living amoebae that can produce an invasive, blinding inflammatory disease of the cornea, termed Acanthamoeba keratitis. The present study reports the preliminary purification and characterization of a novel plasminogen activator from an ocular isolate of A. castellanii. The parasite-derived enzyme has a molecular mass of approx. 40 kDa and produces a single band of lysis on fibrinogen-agarose zymographs. Activity of the enzyme is completely inhibited by treatment with diisopropylfluorophosphate, indicating that it is a serine protease. The parasite-derived serine protease is not inhibited by amiloride which is a strong inhibitor of urokinase-type plasminogen activator. Additionally, the enzyme is not inhibited by plasminogen activator inhibitor-1 which is the primary physiological inhibitor of both urokinase and tissue-type plasminogen activator. It does not cross-react with antibodies specific for human urokinase or tissue-type plasminogen activator. The parasite-derived enzyme activates plasminogen from several mammalian species, including human, cow and pig. Thus, it is possible that this parasite-derived serine protease contributes to the pathogenesis of Acanthamoeba keratitis.

Capacity of simian virus 40 T antigen to induce self-tolerance but not immunological privilege in the anterior chamber of the eye.

Transgenic mice bearing the simian virus 40 (SV40) large T oncogene developed progressively growing intraocular tumors and displayed characteristics of immunological tolerance to SV40 T antigen. Transgenic mice failed to mount CTL responses to SV40 T antigen-bearing tumor cell lines derived from the transgenic intraocular tumors. Spleen cells from transgenic hosts were able to prevent the in vivo and in vitro generation of CTL responses by lymphocytes from normal syngeneic FVB/N mice. Adoptive transfer of spleen cells from tolerant transgenic donors temporarily inhibited the immunological rejection of SV40 T antigen-positive tumor cells transplanted to normal syngeneic FVB/N recipients. Thus, introduction of SV40 transforming sequences into the mouse germline induced tolerance to SV40 T antigen. However, in normal FVB/N mice, SV40 T antigen-bearing tumor cells failed to experience immune privilege in the anterior chamber and did not elicit systemic down-regulation of delayed-type hypersensitivity responses that characteristically occur when antigens are introduced into the anterior chamber. The results indicate that within the anterior chamber of the eye, SV40 T antigen-bearing cells are perceived by the host's immune system much differently than are other categories of antigen. Thus, SV40 T antigen effectively induces self-immunological tolerance when its gene is introduced into the host's germline but fails to experience immunological privilege in the anterior chamber of the eye in normal hosts.

Effect of steroids on Acanthamoeba cysts and trophozoites.

PURPOSE: Topical steroids are frequently used to control corneal inflammation and uveitis or is administered after surgery, to prevent corneal graft rejection. This study was undertaken to determine whether steroids could affect the pathogenicity of Acanthamoeba castellanii. METHODS: The effect of dexamethasone phosphate on excystment, proliferation, and encystment of trophozoites and cysts of A. castellanii was examined in vitro. Cytolysis capacity of steroid-treated Acanthamoeba was quantified by a spectrophotometric assay, and plasminogen activators were measured by a fibrinolysis assay. The influence of steroid treatment on corneal infection in a Chinese hamster model of Acanthamoeba keratitis was examined in vivo. RESULTS: Treatment of Acanthamoeba cysts with dexamethasone induced 4- to 10-fold increases in the number of trophozoites compared with untreated control cultures. Acceleration of trophozoite proliferation was observed when trophozoites were treated with dexamethasone. However, dexamethasone treatment did not affect encystment of Acanthamoeba trophozoites. Dexamethasone-treated trophozoites or cysts induced a significant cytopathic effect on corneal epithelial cells compared with untreated organisms. Supernatants collected from either dexamethasone-treated or untreated organisms failed to lyse corneal epithelial cells. Treatment of organisms with dexamethasone had no effect on production of plasminogen activators by Acanthamoeba trophozoites. Intramuscular injection of dexamethasone had a profound effect on the incidence, severity, and chronicity of keratitis. Keratitis in dexamethasone-treated hamsters was significantly more severe at all time points than in untreated animals (P < 0.05). CONCLUSIONS: These findings indicate that exposure of Acanthamoeba trophozoites and cysts to dexamethasone increases the pathogenicity of the organisms. The results emphasize the importance of maintaining adequate amebicidal therapy if a topical steroid is used in the management of Acanthamoeba keratitis.

Impact of oral immunization with Acanthamoeba antigens on parasite adhesion and corneal infection.

PURPOSE: To determine whether oral immunization mitigates ongoing Acanthamoeba castellanii corneal infections in pigs. METHODS: Pigs were orally immunized with aqueous Acanthamoeba antigen mixed with cholera toxin (Ac-CT) or with saline, before or after ocular infection with A. castellanii. Mucosal secretions (i.e., tears and enteric wash) were tested for Acanthamoeba-specific IgA by enzyme-linked immunosorbent assay. Enteric washes were used as a source of IgA in assays measuring the binding of trophozoites to Chinese hamster corneal epithelial (CHCE) cells. RESULTS: Pigs immunized with Ac-CT before ocular challenge with A. castellanii had significant anti-Acanthamoeba IgA antibody titers in their tears and enteric washes and were protected against ocular infection. Enteric washes from orally immunized pigs inhibited trophozoite binding to CHCE cells in vitro by more than 75%. By contrast, pigs immunized after corneal infections had been established displayed keratitis of the same severity and duration as that in control pigs. However, 80% of the orally immunized animals were resistant to rechallenge with Acanthamoeba-laden contact lenses, whereas none of the control animals was resistant. CONCLUSIONS: Oral immunization with Ac-CT protects against Acanthamoeba keratitis when administered before corneal challenge. However, delaying oral immunization until after corneal disease is established fails to mitigate keratitis. The appearance of parasite-specific tear IgA correlates with protection and may act by preventing the parasite's binding to the corneal epithelium.

The role of macrophages in Acanthamoeba keratitis.

PURPOSE: Macrophages are thought to be the first line of defense in many infectious diseases and are present in high numbers in corneas with Acanthamoeba keratitis. Conjunctival macrophage depletion was performed in an animal model of Acanthamoeba infection to determine the importance of macrophages in this disease. METHODS: Selective elimination of macrophages was achieved by repeated subconjunctival injection of liposomes containing dichloromethylene diphosphonate in a Chinese hamster model of Acanthamoeba keratitis. RESULTS: Macrophage depletion affected the incidence, severity, and chronicity of keratitis. The incidence of infection in normal animals was approximately 60% but rose to 100% on day 4 in animals treated with liposomes containing dichloromethylene diphosphonate (C12MDP-LIP). Moreover, the clinical appearance of the keratitis in the C12MDP-LIP group was much more severe than in animals treated with liposomes containing phosphate-buffered saline at all time points. There was also a major change in the chronicity of keratitis, with an earlier onset and a prolonged and chronic course in the C12MDP-LIP treated hamsters. CONCLUSIONS: The profound exacerbation of Acanthamoeba keratitis in hamsters treated with C12MDP-LIP strongly suggests that macrophages play an important role in corneal infection with Acanthamoeba trophozoites, probably by acting as a first line of defense and eliminating significant numbers of Acanthamoeba trophozoites.

Characterization of intraocular tumors arising in transgenic mice.

PURPOSE: To characterize intraocular tumors that arise by in situ transformation in the choroid-retinal pigment epithelium (RPE) in transgenic mice bearing the SV40 oncogene under the control of the mouse tyrosinase promoter. METHODS: Tumors from TySV40 transgenic mice were characterized in vivo and in vitro by immunohistology, compound microscopy, and electron microscopy. Tumor cell lines were established and characterized for growth and metastatic potential in the eyes of nude mice. RESULTS: On light microscopy, ocular tumors were predominantly epithelioid, although occasional clusters of spindle cells were also present. Transmission electron microscopy revealed the presence of numerous basal infoldings and abundant multilaminated basement membranes on the ocular tumors. Tumors stained with antibodies to melanoma-associated antigens, gangliosides GD2 and GD3, and the SV40 T antigen. Radiolabeled transgenic tumor cells preferentially localized in the liver after intravenous injection in normal mice. Intracamerally transplanted transgenic tumors metastasized from the eyes to the livers of nude mice. CONCLUSIONS: In TySV40 transgenic mice, intraocular tumors develop that arise at the choroid-RPE interface, and they display morphologic and ultrastructural features consistent with RPE carcinomas. However, the transgenic tumors express melanoma-associated antigens and a propensity to metastasize to the liver, two features characteristic of uveal melanomas. The TySV40 transgenic murine tumors represent potentially useful tools for investigations into the biology and metastasis of intraocular neoplasms.

The role of contact lenses, trauma, and Langerhans cells in a Chinese hamster model of Acanthamoeba keratitis.

PURPOSE: To determine the role of contact lenses, corneal trauma, and Langerhans cells in the development of keratitis caused by Acanthamoeba organisms in Chinese hamsters. METHODS: Various methods were used to induce corneal infections in Chinese hamsters, including application of parasite-laden contact lenses. The role of corneal epithelial defects in promoting parasite binding was examined in vitro in a microscopic binding assay. The role of corneal abrasion in the development of Acanthamoeba keratitis was also examined in Chinese hamsters exposed to parasite-laden contact lenses. Other experiments evaluated the effect of infiltrating Langerhans cells on the incidence and severity of Acanthamoeba keratitis. RESULTS: Corneal epithelial defects promoted extensive parasite binding to abraded corneas compared to intact, nonabraded counterparts. Corneal abrasion was absolutely necessary for the induction of Acanthamoeba keratitis in hamsters infected with contaminated contact lenses. Infection was never detected unless the corneas were abraded before exposure to parasite-laden contact lenses. The presence of Langerhans cells in corneas prevented the development of Acanthamoeba keratitis. CONCLUSIONS: The highest incidence of Acanthamoeba keratitis occurs in corneas expressing epithelial defects and exposed to parasite-laden contact lenses. The presence of Langerhans cells in corneas exposed to parasite-laden contact lenses prevents the development of Acanthamoeba keratitis.

Role of mucosal IgA in the resistance to Acanthamoeba keratitis.

PURPOSE: To determine whether oral immunization with Acanthamoeba castellanii antigens elicits mucosal antibodies of the IgA isotype and whether mucosal antibodies affect parasite adhesion to the corneal epithelium. METHODS: Chinese hamsters were immunized with 100 microg aqueous Acanthamoeba antigen mixed with cholera toxin (Ac-CT) and subsequently challenged with parasite-laden contact lenses that were applied to abraded corneal surfaces. Tears and stool samples were examined for the presence of Acanthamoeba-specific IgA antibodies by enzyme-linked immunosorbent assay (ELISA). The effect of mucosal antibody on trophozoite binding to corneal epithelium and viability of trophozoites was examined in vitro. RESULTS: Hamsters immunized orally with Ac-CT showed significantly lower infection rates than did control groups (21.4% versus 72.6%). ELISA analysis of mucosal specimens showed the presence of parasite-specific IgA in stool samples and tears from hamsters orally immunized with Ac-CT, but not in control animals. In vitro assays showed that anti-Acanthamoeba IgA did not affect parasite viability. However, mucosal anti-Acanthamoeba IgA profoundly inhibited (>75%) the binding of parasites to corneal epithelial cells in vitro. CONCLUSIONS: Oral immunization with Ac-CT induces the production of parasite-specific IgA in mucosal secretions and prevents corneal infection. Mucosal antibody does not affect the viability of Acanthamoeba trophozoites but seems to prevent infection by inhibiting parasite binding to the corneal epithelium.

A pig model of Acanthamoeba keratitis: transmission via contaminated contact lenses.

A model of contact lens-induced Acanthamoeba keratitis was developed in Yucatan micropigs. Pigs fitted with parasite-laden soft contact lenses developed corneal infections that clinically and histopathologically mimicked the human counterpart. Three distinct stages of disease became apparent and were categorized as: acute, condensed infiltrate, and resolution stages. Viable parasites were isolated from corneal scrapings and smears were taken during the acute and condensed infiltrate stages. In addition, cysts could be identified deep within the stroma of histological specimens taken during the resolution stages. The characteristic dense, white ring-like infiltrates, stroma edema, keratic precipitates, and the chronic nature of the infections were similar to those observed in human Acanthamoeba keratitis. Histopathological examination of infected corneas revealed extensive neutrophilic infiltrates, stromal necrosis, and disorganization of the collagen lamellae. The strong correlation between the clinical and histopathologic features of contact lens-induced Acanthamoeba keratitis in the pig as well as the anatomical similarity of the pig eye with the human eye make the porcine model a valuable tool for investigations of the immunology, cell biology, and therapy for Acanthamoeba keratitis.

Inhibition of intraocular tumor growth by topical application of the angiostatic steroid anecortave acetate.

PURPOSE: This study examined the effect of an angiostatic agent on the growth of a highly vascularized intraocular tumor. METHODS: A murine uveal melanoma cell line (99E1) was transplanted intracamerally into athymic nude BALB/c mice. Mice were treated topically three times per day beginning on the day of tumor transplantation and continuing through day 28. Groups included (a) 1% anecortave acetate, (b) vehicle control, or (c) no treatment. Tumor growth was scored clinically according to the volume of anterior chamber occupied by tumor. Intraocular tumor weights were determined on days 10, 14, 21, and 28. The effect of the test agents on tumor cell proliferation was examined in vitro by [3H]thymidine incorporation. RESULTS: Tumors grew progressively in untreated mice and mice treated with the vehicle; tumors filled the entire eye by day 20 and frequently perforated the globe by day 21. By contrast, tumors treated with anecortave acetate grew significantly slower (P < 0.025) and did not perforate the eye. On days 21 and 28 the net tumor weight of the AL-3789-treated animals was 40% to 30% of controls (P < 0.05). Tumor inhibition was presumably due to the angiostatic properties of anecortave acetate because the compound did not affect tumor cell proliferation in vitro. CONCLUSIONS: The topical ocular administration of anecortave acetate restricted the growth of a highly vascularized angiogenic intraocular tumor.

In vitro and in vivo tumoricidal properties of a pathogenic/free-living amoeba.

The chemotactic and tumoricidal properties of the pathogenic/free-living amoeba Acanthamoeba castellanii were examined in vivo and in vitro. A. castellanii trophozoites displayed strong positive chemotactic responses to human melanoma (OCM-1) and murine melanoma (D5.1G4) cells. Although the parasites typically invade and destroy the corneal epithelium and stroma, positive chemotactic responses were not detected against extracts of either of these corneal elements. In vitro studies revealed that viable parasites, as well as cell-free parasite lysates, produced swift and extensive cytolysis of a wide variety of tumor cells. The tumoricidal properties of A. castellanii were examined in vivo and revealed that injection of viable parasites or cell-free parasite lysates into progressively growing subcutaneous melanomas resulted in 83% and 53% reductions in the tumor masses compared with untreated controls. The feasibility of utilizing the tumoricidal properties of pathogenic/free-living amoebae and their cell-free products in the treatment of drug-resistant or radioresistant tumors warrants further investigation.

Antibody-dependent neutrophil-mediated killing of Acanthamoeba castellanii.

Neutrophils from naive rats lysed low numbers of Acanthamoeba castellanii in the presence of normal rat serum and significantly higher numbers of the parasite in the presence of serum from immunized rats. With normal rat serum, neutrophils from rats immunized with crude parasite extract or from naive rats killed similar percentages of A. castellanii. However, neutrophils from immunized rats killed a significantly greater percentage of parasites in the presence of serum from immunized rats than was seen with any other combination of serum and neutrophils. The addition of supernatant from cultures of concanavalin A-stimulated rat spleen cells to incubations of the parasite in the presence of neutrophils from naive or immunized rats and immune serum resulted in the highest levels of amoebolysis seen in this study. This study has shown that neutrophils from naive rats or from rats immunized with A. castellanii antigen display a very limited amoebolytic capability which is significantly augmented in the presence of serum from immunized rats and further boosted by the addition of supernatant from Con A-stimulated rat spleen cell cultures.