Post-replication repair and recombination in uvrA umuC strains of Escherichia coli are enhanced by vanillin, an antimutagenic compound

Effects of vanillin on UV killing of umuC mutant strains of E. coli were investigated in order to analyze the antimutagenic role of vanillin in mutagenesis. UV-irradiated uvrA umuC cells showed higher survival when plated on medium containing vanillin rather than medium without vanillin. This increased survival associated with exposure to vanillin was observed more clearly in uvrA umuC lexA(Ind-) and uvrA umuC recF strains. However, the effect was inhibited by additional recB recC mutations and completely blocked by an additional recA mutation. As far as tested the increased survival of UV-treated cells by vanillin was dependent on a capacity for genetic recombination. The effect of vanillin on recombination frequency between 2 plasmid DNA, pATH4 (Cmr Tcs) and pBMX7 (Apr Tcs), in a uvrA umuC background was investigated. A significantly higher frequency of plasmid recombination was observed when vanillin was present in the culture medium. These findings suggest that the antimutagenic effect of vanillin is the result of enhancement of a recA-dependent, error-free, pathway of post-replication repair.     

Effects of antimutagenic flavourings on SCEs induced by chemical mutagens in cultured Chinese hamster cells

Effects of antimutagenic flavourings such as vanillin, ethylvanillin, anisaldehyde, cinnamaldehyde, coumarin and umbelliferone on the induction of SCEs by MMC were investigated in cultured Chinese hamster ovary cells. None of these 6 flavourings showed any SCE-inducing activity by themselves. However, an obvious increase in the frequencies of SCEs was observed when MMC-pretreated cells were cultured in the presence of each flavouring. All these compounds have either an alpha, beta-unsaturated carbonyl group or a carbonyl functionality neighbouring the phenyl group which may react with an enzyme SH-group and cause higher-order structure changes. SCE-enhancing effects of vanillin were further investigated on 6 other kinds of mutagens. Vanillin was also effective on SCEs induced by EMS, ENNG, ENU or MNU. On the other hand, MMS- or MNNG-induced SCEs were not influenced at all by vanillin. SCE-enhancing effects of vanillin seemed to be dependent on the quality of lesions in DNA.     

In vivo anticlastogenic and antimutagenic effects of tannic acid in mice

The anticlastogenic effect of tannic acid was studied in vivo in the mouse micronucleus test. The frequencies of micronuclei induced by mitomycin C, ethyl nitrosourea (ENU) or 4-nitroquinoline 1-oxide in mouse bone marrow cells were decreased by the oral administration of tannic acid 6 h before the mutagen injection. The observed suppressing effect was not a reflection of a delay in the formation of micronuclei by the cytotoxic effect of tannic acid. The antimutagenic effect of tannic acid was also investigated in vivo in the mouse spot test using male PW and female C57BL/10 mice. Tannic acid was given orally to pregnant females 6 h before the intraperitoneal injection of ENU on the 10th day of pregnancy. The frequency of pups with recessive color spots induced by ENU was decreased by the administration of tannic acid. The observed decrease was not due to toxic effects on the embryo. These results indicate that tannic acid acts as an anticlastogen and antimutagen in vivo.     

The possible role of probiotics as dietary antimutagen.

Possible antimutagenic actions of probiotics--mainly lactic acid bacteria--were examined using in vitro and in vivo test systems. In the Ames test with Salmonella typhimurium TA1538 beef extract and nitrosated beef extract were used as mutagens. L. casei showed high antimutagenic activity on mutagenicity induced by nitrosated beef extract only without S9 mix, whereas Omniflora (a lyophilized preparation of lactobacilli and E. coli) and its cell-free culture broth exhibited antimutagenic action only on beef extract. The actions of probiotics were more homogeneous when living animals were used in the tests. Using busulfan as a mutagen both the chromosome aberration test (with Chinese hamster bone marrow cells) and the micronucleus test (with bone marrow cells of Chinese hamsters and mice) showed strong anticlastogenic action when L. casei, Omniflora or yoghurt (with living bifiobacteria) were given orally at the same time as the mutagen. Lactobacilli were effective also after i.p. injection. Cell-free culture broths had no or only weak antimutagenic effects. Mutagen-induced chromosome aberrations and micronuclei were reduced by up to 80% by the lactobacilli.     

The possible role of probiotics as dietary antimutagens

Possible antimutagenic actions of probiotics - mainly lactic acid bacteria - were examined using in vitro and in vivo test systems.In the Ames test with Salmonella typhimurium TA1538 beef extract and nitrosated beef extract were used as mutagens. L. casei showed high antimutagenic activity on mutagenicity induced by nitrosated beef extract only without S9 mix, whereas Omniflora (a lyophilized preparation of lactobacilli and E. coli and its cellfree culture broth exhibited antimutagenic action only on beef extract.The actions of probiotics were more homogeneous when living animais were used in the tests. Using busulfan as a mutagen both the chromosome aberration test (with Chinese hamster bone marrow cells) and the micronucleus test (with bone marrow cells of Chinese hamsters and mice) showed strong anticlastogenic action when L. casei, Omniflora or yoghurt (with living bifiobacteria) were given orally at the same time as the mutagen. Lactobacilli were effective also after i.p. injection. Cell-free culture broths had no or only weak antimutagenic effects. Mutagen-induced chromosome aberrations and micronuclei were reduced by up to 80% by the lactobacilli.     

Suppressing effect of antimutagenic flavorings on chromosome aberrations induced by UV-light or X-rays in cultured Chinese hamster cells

Chromosome aberrations induced by UV-light or X-rays were suppressed by the post-treatment with antimutagenic flavorings, such as anisaldehyde, cinnamaldehyde, coumarin, and vanillin. UV- or X-ray-irradiated surviving cells increased in the presence of each flavoring. X-ray-induced breakage-type and exchange-type chromosome aberrations were suppressed by the vanillin treatment in the G1 phase of the cell cycle and a greater decrease in the number of X-ray-induced chromosome aberrations during G1 holding was observed in the presence of vanillin. Furthermore, a greater decrease in the number of X-ray-induced DNA single-strand breaks was observed in the presence of vanillin. Treatment with vanillin in the G2 phase suppressed UV- and X-ray-induced breakage-type but not exchange-type chromosome aberrations. The suppression of breakage-type aberrations was assumed to be due to a modification of the capability of the post-replicational repair of DNA double-strand breaks. These G1- and G2-dependent anticlastogenic effects were not observed in the presence of 2',3'-dideoxythymidine, an inhibitor of DNA polymerase beta. Based on these results, the anticlastogenic effect of vanillin was considered to be due to the promotion of the DNA rejoining process in which DNA polymerase beta acts.     

Antimutagenic effect of Agaricus blazei Murrill mushroom on the genotoxicity induced by cyclophosphamide

Agaricus blazei Murrill extracts have previously been shown to have anticarcinogenic and antimutagenic properties. These results suggest that antimutagenic activity, besides the modulation of the immune system, might be involved in the anticarcinogenic action of A. blazei. To investigate the possible antimutagenic effect of A. blazei in vivo, we evaluated its effect on clastogenicity induced by cyclophosphamide (CP) in mice, using the micronucleus test in bone marrow (MNPCE) and in peripheral blood (MNRET). Male Swiss mice were treated with CP (25 or 50mg/kg i.p.) or with CP plus mushroom solution at three different temperatures: 4, 21, and 60 degrees C. Aqueous solution of a mixture from various lineages of the mushroom inhibited induction of micronuclei by CP in bone marrow and in peripheral blood of mice. In contrast to the mixture of lineages, a single isolated lineage did not lead to a reduction of CP-induced MN frequencies in either bone marrow or blood cells of mice. The results suggest that under certain circumstances these mushrooms exhibit antimutagenic activities that might contribute to an anticarcinogenic effect.     

Antitumor activity of Pulsatilla chinensis (Bunge) Regel saponins in human liver tumor 7402 cells in vitro and in vivo

Pulsatilla chinensis (Bunge) Regel is a Chinese medicinal herb for "blood-cooling" and detoxification. Now it is used for the treatment of malignant tumor, but the antitumor mechanisms and toxic side effects of P. chinensis are unclear. The present study was undertaken to investigate if P. chinensis saponins (PRS) possesses anticancer effects and toxic side effects in human liver tumor 7402 cells in vitro and vivo. 7402 cells were treated with different concentrations of PRS for 24h. Cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell apoptosis was assessed by flow cytometry. The in vivo effect of PRS on 7402 tumor cells transplanted in athymic nude mice was investigated. 15 saponins were isolated and identified from PRS. PRS inhibited the proliferation of human liver tumor 7402 cells in vitro by apoptosis. 19 days after administration of PRS (100, 200mg/kg), the weight of tumor mass was markly decreased in nude mice. The anti-tumor effect of PRS in vivo was associated with a significant increase in the 7402 apoptosis rate. Although PRS inhibited the weight of mice, it showed almost no effect on leukocyte number, liver and spleen weight index. Light microscopic histopathological examination showed that PRS had no specific lesion in organ. These results suggested that P. chinensis saponins exert potential anticancer activity in treating tumors in nude mice and no toxic side effects.     

Vanillins--a novel family of DNA-PK inhibitors

Non-homologous DNA end-joining (NHEJ) is a major pathway of double strand break (DSB) repair in human cells. Here we show that vanillin (3-methoxy-4-hydroxybenzaldehyde)—a naturally occurring food component and an acknowledged antimutagen, anticlastogen and anticarcinogen—is an inhibitor of NHEJ. Vanillin blocked DNA end-joining by human cell extracts by directly inhibiting the activity of DNA-PK, a crucial NHEJ component. Inhibition was selective and vanillin had no detectable effect on other steps of the NHEJ process, on an unrelated protein kinase or on DNA mismatch repair by cell extracts. Subtoxic concentrations of vanillin did not affect the ATM/ATR-dependent phosphorylation of Chk2 or the S-phase checkpoint response after ionising radiation. They significantly potentiated the cytotoxicity of cisplatin, but did not affect sensitivity to UVC. A limited screen of structurally related compounds identified two substituted vanillin derivatives that were 100- and 50-fold more potent than vanillin as DNA-PK inhibitors. These compounds also sensitised cells to cisplatin. The inhibition of NHEJ is consistent with the antimutagenic and other biological properties of vanillin, possibly altering the balance between DSB repair by NHEJ and homologous recombination.     

In vitro and in vivo antiangiogenic properties of the serpin protease nexin-1

The serpin protease nexin-1 (PN-1) is expressed by vascular cells and secreted by platelets upon activation, and it is known to interact with several modulators of angiogenesis, such as proteases, matrix proteins, and glycosaminoglycans. We therefore investigated the impact of PN-1 on endothelial cell angiogenic responses in vitro and ex vivo and in vivo in PN-1-deficient mice. We found that PN-1 is antiangiogenic in vitro: it inhibited vascular endothelial growth factor (VEGF)-induced endothelial cell responses, including proliferation, migration, and capillary tube formation, and decreased cell spreading on vitronectin. These effects do not require the antiprotease activity of PN-1 but involve PN-1 binding to glycosaminoglycans. In addition, our results indicated that PN-1 does not act by blocking VEGF binding to its heparan sulfate proteoglycan coreceptors. The results obtained in vitro were supported ex vivo in PN-1-deficient mice, where the microvascular network sprouting from aortic rings was significantly enhanced. Moreover, in vivo, neovessel formation was promoted in the Matrigel plug assay in PN-1-deficient mice compared to wild-type mice, and these effects were reversed by the addition of recombinant PN-1. Taken together, our results demonstrate that PN-1 has direct antiangiogenic properties and is a yet-unrecognized player in the angiogenic balance.     

Suppression of mitomycin C-induced micronuclei in mouse bone marrow cells by post-treatment with vanillin

Induction of micronuclei by mitomycin C (MMC) in mouse bone marrow cells was suppressed by post-treatment with vanillin, a component of vanilla essence flavour. Vanillin was given orally to mice 7.5 h after intraperitoneal injection of 2 mg/kg MMC. Post-treatment with vanillin at 500 mg/kg caused about 50% decrease in the frequency of micronucleated polychromatic erythrocytes (MN-PCEs). The effect of vanillin administration on the time-course of formation of MN-PCEs was also investigated. The suppressing effect was not due to a delay in the formation of MN-PCEs by the cytotoxic action of vanillin. Vanillin acts as an anticlastogenic factor in vivo.     

Regulation of prostaglandin biosynthesis by nitric oxide is revealed by targeted deletion of inducible nitric-oxide synthase

We investigated the effects of targeted deletion of the inducible NO synthase (iNOS) gene on the formation of prostaglandins in vivo and ex vivo. Peritoneal macrophages were obtained from control and iNOS-deficient mice, and prostaglandin E(2) (PGE(2)) was quantified after stimulation with gamma-interferon and lipopolysaccharide to induce COX-2. Total nitrate and nitrite production was completely abolished in cells from iNOS-deficient animals compared with control cells. PGE(2) formation by cells from iNOS-deficient animals was decreased compared with cells from control animals 80% at 12 h (0.85 +/- 0.90 ng/10(6) cells versus 15.4 +/- 2.1 ng/10(6) cells, p < 0.01) and 74% at 24 h (9.4 +/- 4.3 ng/10(6) cells versus 36.8 +/- 4.1 ng/10(6) cells, p < 0.01). COX-2 protein expression was not significantly different in cells from control or knockout animals. Levels of PGE(2) in the urine of iNOS-deficient mice were decreased 78% (0.24 +/- 0.14 ng/mg of creatinine versus 1.09 +/- 0.66 ng/mg of creatinine, p < 0.01) compared with control animals. In addition, the levels of urinary F(2)-isoprostanes, an index of endogenous oxidant stress, were significantly decreased in iNOS-deficient animals. In contrast, the levels of thromboxane B(2) derived from platelets allowed to aggregate ex vivo were significantly increased in iNOS-deficient mice compared with wild-type mice. These studies support the hypothesis that NO and/or NO-derived species modulate cyclooxygenase activity and eicosanoid production in vivo.     

Down-modulation of lymphoproliferation and interferon-gamma production by beta-glucan derived from Saccharomyces cerevisiae

beta-glucan, one of the major cell wall components of Saccharomyces cerevisiae, has been found to enhance immune functions. This study investigated in vivo and in vitro effects of beta-glucan on lymphoproliferation and interferon-gamma (IFN-gamma) production by splenic cells from C57BL/6 female mice. All experiments were performed with particulate beta-glucan derived from S. cerevisiae. Data demonstrated that both, i.p. administration of particulate beta-glucan (20 or 100 micrograms/animal) and in vitro stimulation of splenic cells (20 or 100 micrograms/ml of culture) decreased lymphoproliferation and IFN-gamma production induced by concanavalin A. These results suggest that beta-glucan can trigger a down-modulatory effect regulating a deleterious immune system hyperactivity in the presence of a strong stimulus.     

Caspase-8 activity prevents type 2 cytokine responses and is required for protective T cell-mediated immunity against Trypanosoma cruzi infection

During Trypanosoma cruzi infection, T cells up-regulate caspase-8 activity. To assess the role of caspase-8 in T cell-mediated immunity, we investigated the effects of caspase-8 inhibition on T cells in viral FLIP (v-FLIP) transgenic mice. Compared with wild-type controls, increased parasitemia was observed in v-FLIP mice infected with T. cruzi. There was a profound decrease in expansion of both CD4 and CD8 T cell subsets in the spleens of infected v-FLIP mice. We did not find differences in activation ratios of T cells from transgenic or wild-type infected mice. However, the numbers of memory/activated CD4 and CD8 T cells were markedly reduced in v-FLIP mice, possibly due to defective survival. We also found decreased production of IL-2 and increased secretion of type 2 cytokines, IL-4 and IL-10, which could enhance susceptibility to infection. Similar, but less pronounced, alterations were observed in mice treated with the caspase-8 inhibitor, zIETD. Furthermore, blockade of caspase-8 by zIETD in vitro mimicked the effects observed on T. cruzi infection in vivo, affecting the generation of activated/memory T cells and T cell cytokine production. Caspase-8 is also required for NF-kappaB signaling upon T cell activation. Blockade of caspase-8 by either v-FLIP expression or treatment with zIETD peptide decreased NF-kappaB responses to TCR:CD3 engagement in T cell cultures. These results suggest a critical role for caspase-8 in the establishment of T cell memory, cell signaling, and regulation of cytokine responses during protozoan infection.     

Anti-tumor activity of recombinant tumor necrosis factor on mouse fibrosarcoma in vivo and in vitro

The experiments presented were designed first to determine the effects of rTNF on the methylcholanthrene-induced fibrosarcoma (FSA-1) in C3H/JSed mice and second to determine whether the observed effects are the result of direct action by rTNF on the tumor or whether rTNF acts as a mediator of other effector mechanisms. Mice received syngeneic FSA-1 fibrosarcoma cells either s.c. or i.v. in order to evaluate growth of transplantable solid tumor or lung metastases, respectively. The range of dosages, from 10(2) to 2 x 10(5) U of rTNF, was administered i.v. at different intervals after the tumor cell injection. Early injection of 10(3) to 10(4) U of rTNF reduced the growth of s.c. injected tumor and the number of lung metastases in i.v. injected mice. In both cases, survival of mice was also prolonged. However, in vitro treatment of FSA-1 tumor cells with rTNF did not result in the reduction of their proliferating activity after injection into mice, although direct cytostatic and moderate cytotoxic activity of rTNF in vitro was demonstrated. To identify whether other cellular mechanisms are involved in the effects observed in vivo, the anti-tumor activity of rTNF-treated spleen cells was evaluated in vitro using a 75Se release assay. Whereas nontreated spleen cells demonstrated very low cytotoxic activity in this system, the cells from rTNF-treated mice showed marked increase in the cytotoxicity against syngeneic tumor cells. These results suggest that the anti-tumor activity of rTNF represents a combination of its direct effect on tumor cells and indirect effects involving host immune mechanisms.     

Myelosuppressive effects in vivo of purified recombinant murine macrophage inflammatory protein-1 alpha.

Purified recombinant murine macrophage inflammatory protein-1 alpha (rmuMIP-1 alpha), a cytokine with myelopoietic activity in vitro, was assessed in vivo by injection into C3H/HeJ mice for effects on proliferation (percentage of cells in S phase DNA synthesis of the cell cycle) and absolute numbers of granulocyte-macrophage, erythroid, and multipotential progenitor cells in the femur and spleen, and on nucleated cellularity in the bone marrow, spleen, and blood. rmuMIP-1 alpha rapidly decreased cycling rates (at 2 to 10 micrograms/mouse i.v.) and absolute numbers (at 5 to 10 micrograms/mouse i.v.) of myeloid progenitor cells in the marrow and spleen. These effects were dose- and time-dependent and reversible. Suppressive effects were noted within 3 to 24 h for cell cycling and absolute numbers of progenitor cells in the marrow and spleen, and by 48 h for circulating neutrophils. A study comparing the effects of i.v. injection of rmuMIP-1 alpha versus rmuMIP-1 beta, a biochemically similar molecule but with no myelosuppressive effects in vitro, demonstrated myelosuppression in vivo by rmuMIP-1 alpha, but not by rmuMIP-1 beta. The results suggest that rmuMIP-1 alpha has myelosuppressive activity in vivo and offers the possibility that it may be a useful adjunct to treatments involving cytotoxic drugs because of its reversible suppressive effects on normal progenitor cell cycling.     

A critical role for regulatory T cells in driving cytokine profiles of Th17 cells and their modulation of glioma microenvironment

IL-17A, produced by Th17 cells, may play a dual role in antitumor immunity. Using the GL261-glioma model, we investigated the effects of Th17 cells on tumor growth and microenvironment. Th17 cells infiltrate mouse gliomas, increase significantly in a time-dependent manner similarly to Treg and do not express Foxp3. To characterize the direct effects of Th17 cells on GL261 murine gliomas and on tumor microenvironment, we isolated IL-17-producing cells enriched from splenocytes derived from naïve (nTh17) or glioma-bearing mice (gTh17) and pre-stimulated in vitro with or without TGF-β. Spleen-derived Th17 cells co-expressing IL-17, IFN-γ and IL-10, but not Treg marker Foxp3, were co-injected intracranially with GL261 in immune-competent mice. Mice co-injected with GL261 and nTh17 survived significantly longer than gTh17 (P < 0.006) and gliomas expressed high level of IFN-γ and TNF-α, low levels of IL-10 and TGF-β. In vitro IL-17 per se did not exert effects on GL261 proliferation; in vivo gliomas grew equally well intracranially in IL-17 deficient and wild-type mice. We further analyzed relationship between Th17 cells and Treg. Treg were significantly higher in splenocytes from glioma-bearing than naïve mice (P = 0.01) and gTh17 produced more IL-10 than IFN-γ (P = 0.002). In vitro depletion of Treg using PC61 in splenocytes from glioma-bearing mice causes increased IL-17/IFN-γ cells (P = 0.007) and decreased IL-17/IL-10 cells (P = 0.03). These results suggest that Th17 polarization may be induced by Treg and that Th17 cells in gliomas modulate tumor growth depending on locally produced cytokines.     

Inhibition of experimental autoimmune thyroiditis in mice by anti-I-A antibodies

Experimental autoimmune thyroiditis is induced in mice by immunization with thyroglobulin emulsified in Freund's complete adjuvant. The disease is characterized both by thyroid infiltration with mononuclear cells and by circulating thyroglobulin antibodies. The magnitude of the thyroid infiltration and the titer of thyroglobulin antibodies are controlled by genes in the I-A subregion of the major histocompatibility complex (H-2). We investigated the in vivo effect of monoclonal anti-Ia antibodies on experimental autoimmune thyroiditis in susceptible mice. Antibodies were given around the time of immunization, later after immunization, and to mice with established disease. Monoclonal antibody produced by the hybridoma line 10-3.6 (anti-I-Ak, s, u, v, z, f) completely prevented both production of thyroglobulin antibodies and thyroid infiltrates, when given shortly before or at the time of antigen administration. This effect was dose-dependent and this monoclonal antibody decreased the severity of the disease when given after the antigen challenge but did not fully suppress established thyroiditis. The same antibody markedly decreased the number of B lymphocytes in the spleen and decreased the thyroglobulin-induced spleen cell proliferation when either given in vivo or added in vitro to cell cultures. Antibodies produced by the hybridoma line 11.2.12 (anti-I-Ak) did not show an inhibitory effect on the disease. These experiments suggest that in this model of murine thyroiditis anti-Ia antibodies act on antigen-presenting cells. Furthermore, only one monoclonal antibody, anti-Ia, suppressed the immune response to thyroglobulin, suggesting a possible role for the isotype and specificity of anti-Ia antibody.     

Iron chelators: correlation between effects on Plasmodium spp. and immune functions

Iron chelating agents, which permeate through erythrocytic and parasite membranes, are effective against Plasmodium falciparum in vitro. However, the protective effect in humans is transient. We examined the antiplasmodial capacity of several iron chelators in vitro and in vivo. The chelators 3/3hb/2m and 3/2hb/b (together, MoB) were more effective against P. falciparum in vitro than desferrioxamine (DFO) and Salicylaldehyde isonicotinoyl hydrazone (SIH) (together, DoS). Despite similar pharmacokinetics of all iron chelators, mice infected with Plasmodium vinckei and treated with MoB succumbed to malaria, whereas DoS-treated mice survived. However, even in the surviving mice, peak parasitemias were above 30%. These results indicate that the direct effects of the drugs on the parasites were not responsible alone for the complete recovery of the mice. We suggest that the recovery is related to differential effects of the drugs on various immune functions. We concentrated on the effect of the iron chelators on B cell and T cell proliferation and on allogeneic stimulation (MLR), interleukin-10 (IL-10), gamma-interferon (gamma-IFN), tumor necrosis factor-alpha (TNF-alpha), and radical production. All the iron chelators examined inhibited the in vitro proliferation of B cells and T cells, and MLR. This may explain why iron chelators are only slightly efficient in treating human malaria. However, the inhibitory effects of MoB on B cell and T cell proliferation and on MLR were more pronounced than those of DoS. In addition, the release of free radicals by effector cells was inhibited to a greater extent by MoB than by DoS. These results may explain why MoB, which was more efficient in vitro, was not effective in vivo. The DoS effects on the in vitro secretion of cytokines correlate with their in vivo effect; there was a decrease of IL-10 and a parallel increase in gamma-IFN and TNF-alpha production by human mononuclear cells. MoB, which could not rescue the animals from malaria, did not affect IL-10 and TNF-alpha, but reduced gamma-IFN levels. Identical results were obtained when using monocytes instead of mononuclear cells (except for gamma-IFN, which is not produced by monocytes). Our results indicate that an iron chelator, or any antiparasitic drug that kills the parasites in vitro, should also be selected for further evaluation on the basis of its reaction with immune components; it should not interfere with crucial protective immunological processes, but it may still alleviate parasitemia by positive immune modulation.