Shark cartilage 14 kDa protein as a dendritic cells activator.

Low molecular weight components of shark cartilage are reported to have anti-tumor as well as immuno-stimulating effects. Dendritic cells (DCs) are potent antigen-presenting cells (APCs) that have a key role in establishment of anti-cancer immune response. In this study, the effect of 14 kDa protein from shark cartilage was investigated on stimulation and maturation of dendritic cells. The isolated 14 kDa protein from shark cartilage extract was added to DCs medium during overnight culture and their maturation and T cells stimulation potential was investigated. The majority of shark-cartilage-treated DCs expressed higher levels of maturation markers and were more effective in stimulation of allogenic T cells compared with non-treated DCs (p < 0.05). Our results showed that shark cartilage 14 kDa protein can potentially be used in DC-mediated T-cells stimulation and induction of desirable immune responses in clinical trials such as cancer immunotherapy. However, further studies are required to examine this proposal.

Immunomodulatory Effect of ß-Glucan on Peritoneal Macrophages of Bab1/c Mice.

We assessed the effect of ß-Glucan on macrophages by Griess reagent and viability by MTT assay and cytotoxicity. Assay of macrophages culture supernatants were carried out on WEHI-164 fibrosarcoma cell line as tumor necrosis factor-α bioassay were done. NO release was increased at the dose of 10 µg/ml (P = 0.001) of ß-Glucan while the viability of macrophages in all concentrations was the same. In TNF-α bioassay, the supernatant of macrophages stimulated with ß-Glucan had a significant cytotoxic effect on WEHI-164 cells (P = 0.023). ß-Glucan had a positive effect on increasing tumoricidal activity of macrophages which may help in anti-cancer immune responses.

Tehranolide inhibits cell proliferation via calmodulin inhibition, PDE, and PKA activation.

Tehranolide, natural sesquiterpene lactone with an endoperoxide group, has been shown to inhibit cell growth in cancer cells. Tehranolide was purified from Artemisia diffusa. To detect cell viability and proliferation, MTT assay was performed. In order to determine the role of tehranolide on calmodulin (CaM) structure and activity, its effects were evaluated with fluorescence emission spectra and CaM-mediated activation of phosphodiesterase (PDE1), in comparison with artemisinin. In fact, PDE1 inhibition, cAMP accumulation, and cAMP-dependent protein kinase A (PKA) activation were examined. The inhibitory effect of tehranolide on CaM structure is more than artemisinin. The kinetic analysis of tehranolide-CaM interaction has shown that this agent competitively inhibited the activation of PDE1 without affecting Vmax. Tehranolide increased Km value in higher amounts compared with artemisinin. Moreover, tehranolide had a cytotoxic effect on K562 cell line but not on normal human lymphocytes. Additionally, PDE inhibition and consequent cAMP accumulation and PKA activity were required for inhibiting cancer cell growth by tehranolide. Our results show that tehranolide significantly reduces cell proliferation in a time and dose-dependent manner in K562 cells via CaM inhibition, following PDE inhibition, cAMP accumulation, and consequent PKA activity.

In vitro suppression of dendritic cells by Helicobacter pylori OipA.

BACKGROUND: Outer inflammatory protein A (OipA) has an important role in Helicobacter pylori pathogenesis. In this study, we purified the outer membrane protein and evaluated the effects of this protein on maturation and cytokine production by dendritic cells (DCs). MATERIALS AND METHODS: The oipA gene was inserted into pET28a, and this construct was transformed into Escherichia coli BL21 (DE3). Purification of the recombinant protein was performed by Ni-NTA affinity chromatography. Immature DCs were purified from spleen of C57BL/6 mice with more than 90% purity and were treated with several concentrations of OipA (1-20 µg/mL) overnight. Expression of maturation markers (CD86, CD40, and MHC-II) on the surface of DCs and production of IL-10 and IL-12 were assessed by flow cytometry and ELISA, respectively. RESULTS: The expression of DC maturation markers CD40, CD86, and MHC-II was downregulated on the surface of OipA-treated DCs at concentrations of 10 and 20 µg/mL compared with negative control. Production of IL-10 decreases with increasing OipA concentration at a concentration of 5 µg/mL, but we detected no change in IL-12 production. CONCLUSION: Inability to eliminate H. pylori from stomach is partly due to the evasion of the bacteria from the immune response. DCs are central mediators between innate and adaptive immunity, and DC cytokines direct the types of adaptive immune response. This study indicated that OipA of H. pylori is a DC maturation suppression factor. Previous studies have shown that H. pylori manage tolerogenic programming in DCs leading to long-time gastric colonization. In conclusion, H. pylori OipA helps the establishment of chronic infection with reduction in IL-10 and suppression of DC maturation.

Dual-frequency ultrasound activation of nanomicellar doxorubicin in targeted tumor chemotherapy.

INTRODUCTION: This study investigated the therapeutic effect of dual-frequency sonication (3 MHz and 28 kHz) at low intensity levels in combination with micellar doxorubicin in the treatment of a tumor model of spontaneous breast adenocarcinoma in Balb/c mice. METHODS: We used sonication frequencies 28 kHz and 3 MHz and their dual combinations in the progressive wave mode to enhance acoustic cavitation. Then, the antitumor effect of the simultaneous dual-frequency ultrasound (28 kHz and 3 MHz) at low intensity levels in combination with doxorubicin and micellar doxorubicin injection was investigated in a spontaneous model of breast adenocarcinoma in Balb/c mice. Sixty-three tumor-bearing mice were randomly divided into seven groups: control, sham, sonication with dual frequency, doxorubicin without sonication, doxorubicin with dual-frequency sonication, micellar doxorubicin without sonication, and micellar doxorubicin with dual-frequency sonication. The tumor volume change relative to the initial volume, tumor growth inhibition ratio, the required times for each tumor to reach two (T 2) and five (T 5) times its initial volume, and survival period were the tumor growth delay parameters which were calculated and recorded at various times after treatment. RESULTS: The results of the combination of frequencies 28 kHz (0.04 W/cm(2)) and 3 MHz (2.00 W/cm(2)) showed remarkable enhancement of the cavitation activity compared with single-frequency sonication (P < 0.05). The micellar doxorubicin injection with sonication group showed a significant difference in the relative volume percent parameter compared with the other groups (P < 0.05). Additionally, the T 2 and T 5 times in the micellar doxorubicin with sonication group were significantly higher than in the other groups (P < 0.05). Also, the survival period of the mice in the micellar doxorubicin with sonication group was significantly longer than in the other groups (P < 0.05). These findings were verified histopathologically. CONCLUSION: This study shows that simultaneous combined dual-frequency ultrasound sonication in continuous mode is effective in producing cavitation activity at low intensity. We conclude that dual-frequency sonication with micellar doxorubicin injection extends survival in a murine breast adenocarcinoma model.

Antitumor and immunomodulatory effects of salvigenin on tumor bearing mice.

Development of agents that specifically kill cancer cells and simultaneously elicit antitumor immune response is a step forward in cancer therapy. Immunostimulation can result in eliminating of the cancer cells; immunotherapy is a promising approach in balancing the immune response by Treg. In the present study, we investigated whether the administration of salvigenin contributes to the augmentation of antitumor immunity and the regression of tumor tissues in a mouse model of breast cancer. Salvigenin was purified from Tanacetum canescens, and its effect on the tumor volume was investigated. The splenocyte proliferation, shifting of cytokine profile, and the presence of naturally-occurring CD4+CD25+Foxp3+ Treg cells were assessed to describe the anti-tumor immune response. Our results demonstrated that a significant decrease in the level of IL-4 and increase in the IFN-γ in the animals treated with salvigenin and significant decreased in the level of splenic CD4+CD25+Foxp3+ T regulatory cells. The cytotoxic and immunomodulatory properties of salvigenin were acknowledged in vivo.

Effect of fractionation on treatment outcome in local dual-frequency sonication and Dox-encapsulated nanomicelles.

PURPOSE: The goal of this study was to localize drug release from nanomicelles using dual-frequency sonication at low levels of acoustic intensity. METHODS: In this study, the antitumor effect of simultaneous dual-frequency sonication (28 kHz and 3 MHz) at low levels of acoustic intensity in combination with doxorubicin and micellar doxorubicin injection was assessed in a spontaneous model of breast adenocarcinoma in female Balb/c mice. Sixty-three tumor-bearing mice were randomly grouped into control, sham, dual-frequency sonication, doxorubicin injection with and without dual-frequency sonication, and micellar doxorubicin injection with and without dual-frequency sonication groups. RESULTS: The results of volume change relative to initial volume showed that in the micellar doxorubicin injection with sonication group, this parameter was significantly different from that of the control, sham, sonication, and doxorubicin injection groups (P < 0.05). In addition, the volume began to increase on the 15th day after the start of treatment, which is a good indication to repeat treatment; therefore, another group received an extra treatment on day 15. The animal life span in the micellar doxorubicin with sonication and repeated treatment groups was significantly higher than that in all the other experimental groups except for the micellar doxorubicin injection group (P < 0.05). CONCLUSION: It was concluded that dual-frequency sonication with micellar doxorubicin injection extends the life span relative to doxorubicin injection or dual-frequency sonication alone, and that repeating this treatment on day 15 decreases the rate of tumor growth significantly.

Withdrawal from morphine reduces cell-mediated immunity against herpes simplex virus generated by natural immunization.

In a previous study, the authors have shown that herpes simplex virus type 1 (HSV-1) glycoprotein B DNA vaccine but not live vaccine (non-virulent KOS strain) failed to induce protective immunity against acute HSV-1 challenge in morphine-dependent mice. The present study reports the effect of morphine withdrawal on protective immunity induced by live HSV-1 immunization. BALB/c mice were vaccinated with KOS strain as a live vaccine. Three weeks later, they were exposed to morphine for 14 days. On day 14, withdrawal was induced by administration of normal saline instead of morphine. One day later, immune responses against HSV-1 were assessed by measuring cytotoxicity, lymphocyte proliferation and interferon-γ production. Protection against HSV-1 was assessed by measuring the mortality rate after acute HSV-1 challenge. The results showed that withdrawal from morphine reduces protective immunity against acute HSV-1 challenge. These findings raise the possibility that withdrawal from morphine may increase the susceptibility of drug addicts to infectious diseases.

Comparing the effect of IL-12 genetic adjuvant and alum non-genetic adjuvant on the efficiency of the cocktail DNA vaccine containing plasmids encoding SAG-1 and ROP-2 of Toxoplasma gondii.

Various methods are available for enhancing the potency of DNA vaccines, including employment of different forms of adjuvant. The current study was carried out to evaluate and compare the effects of genetic and non-genetic adjuvants on the immune response stimulated by DNA vaccine. Thus, two adjuvants, IL-12 (genetic adjuvant) and aluminum hydroxide (alum, non-genetic adjuvant), were used with cocktail DNA vaccine containing plasmids encoding complete rhoptry antigen 2 (ROP-2) and surface major antigen 1 (SAG-1) of Toxoplasma gondii. The efficacy of pcROP2+pcSAG1 in stimulation of the immune response against toxoplasmosis with and without adjuvant was evaluated in female BALB/c mice by measuring the level of total IgG antibody and cytokines. The results obtained indicated that after challenging the mice with the fatal RH strain of T. gondii, the survival rates of mice immunized with pcROP2+pcSAG1 (DNA cocktail), pcSAG1+pcROP2+alum, and pcSAG1+pcROP2+IL-12 were significantly greater than that of the control groups (p<0.05). Moreover, measurement of total IgG antibody indicated the significant difference between the control and experimental groups (p<0.05). Finally, the results obtained by measurement of cytokines (IFN-γ and IL-4) showed high levels of IFN-γ and low levels of IL-4 in groups vaccinated with pcROP2+pcSAG1 (DNA cocktail), pcSAG1+pcROP2+alum, and pcSAG1+pcROP2+IL-12 as the experiment groups, in comparison with the controls groups (PBS, pc-DNA3, alum+PBS, and pCAGGS-IL-12+pcDNA3). The results of the study showed that use of adjuvants (IL-12 and alum) coincident with DNA cocktail leads to significant change in the survival rates of the experiment groups in comparison with control groups. Also, there is no significant difference between adjuvants to induce immune responses.

In silico prediction of exposure amino acid sequences of outer inflammatory protein A of Helicobacter pylori for surface display on Eschierchia coli.

BACKGROUND: Outer inflammatory protein A (OipA) is an outer membrane protein of Helicobacter pylori that is involved in inducing IL-8 and intracellular signaling. In this study, we have predicted exposure amino acid sequences of OipA for insertion in permissive sites of CstH subunit of Eschierchia coli CS3 pilli for bacterial surface display. DATABASES: National Center for Biotechnology Institute and Protein Data Bank. Servers: PHD, SABLE, GOR 4, SignalP3.0, TBBpred, PRODIV-TMHMM, TMRPres2D, CPH Models, PHYRE, GETAREA, VADAR, Pep state and pep window. Software: Swiss PDB viewer and Discovery studio. RESULTS: In silico prediction of exposure amino acid sequences of OipA led to detection of six sequences of amino acid, 76-87, 106-112, 170-182, 222-230, 242-258, and 278-290. These sequences inserted between amino acid sequences 66-67, 100-101, and 109-110 of CstH that were predicted by Eskandari et al. as permissive sites of CstH. CONCLUSION: OipA has the ability to induce IL-8 from gastric epithelial cells and some papers are mentioned that this outer membrane protein involve to attachment and intracellular signaling. Receptor of OipA and adhesion motifs on this protein is unknown. Detection of exposure motifs aids to recognition of adhesion motifs and receptor of OipA on gastric epithelial cells. In this study, we have predicted exposure amino acid sequences for insert to subunit CstH of CS3 pilli E. coli for surface display.

Dihydroartemisinin shift the immune response towards Th1, inhibit the tumor growth in vitro and in vivo.

Some investigators have been found that Artemisinin and its derivates have inhibitory effect on growth of cancer cells. Among these derivatives, Dihydroartemisinin (DHA) is well known as a semi-synthetic one. In addition, T cells are proved to be essential for the destruction of cancer cells. In this research, we assessed the effects of DHA on tumor cell growth inhibition in vitro by MTT assay and in vivo by intra tumor injection of DHA against breast cancer. The results showed that the IC(50) values of DHA for RIN pancreatic tumor cell line were 30 µM and significant decrease in the tumor size in vivo. Also we evaluate the effect of DHA on the modulation of immune response in tumor bearing animals; these include the splenocyte proliferation using the BrdU kit; measurement of cytokine profile by ELISA, and evaluate the percentage of T regulatory cells in the spleen by flowcytometry. Our results demonstrated that a significant decrease in the level of IL-4 in the animals treated with DHA and significant decreased in the level of splenic CD4(+)CD25(+) Foxp3(+) T regulatory cells.

Protection of mice by a λ-based therapeutic vaccine against cancer associated with human papillomavirus type 16.

OBJECTIVE: Human papillomavirus (HPV) oncoproteins (i.e. E6 and E7) are constitutively expressed in cervical cancer cells. The proteins are ideal targets to be used for developing therapeutic vaccines against existing HPV-associated carcinomas. To date, whole bacteriophage ('phage')-λ particles, rather than purified 'naked' DNA, have been described as highly efficient delivery vehicles for a DNA vaccine. METHODS: In this study, a safe and efficient λ-based therapeutic cancer vaccine, recombinant λ-ZAP E7 phage, was developed by inserting a HPV16 E7 gene into the Lambda ZAP® cytomegalovirus vector. λ-ZAP E7 phages were employed to immunize mice against the E7-expressing murine tumor cell line (TC-1), which is used as a tumor model in an H-2b murine system. RESULTS: The tumor-bearing mice indicated a significant inhibition of tumor growth after 3 injections of 2 × 10(12) particles of recombinant phages. Released lactate dehydrogenase, interferon-γ and granzyme B from spleen cells and lymphocyte proliferation of spleen cells, which all demonstrate the enhancement of cell-mediated immunity, suggested the phages could be a potent gene delivery system in animal models. CONCLUSION: Our results suggest the recombinant phages can be used as effective biological tools for inducing E7-specific protective immune responses. Hence, the study introduces a possible therapeutic strategy against cervical cancer and other HPV-related neoplasia.

Effect of shark cartilage derived protein on the NK cells activity.

CONTEXT: Shark cartilage has been used for its beneficial effects on various diseases. There are evidences, that shark cartilage stimulates cellular and humoral immune responses, which makes it an anti-tumor and immunomodulator candidate. OBJECTIVE: The immunostimulatory effect of shark cartilage derived proteins on the cytotoxic activity of natural killer (NK) cells from healthy human peripheral blood mononuclear cells was studied. MATERIAL AND METHODS: The shark cartilage was extracted and its bioactive proteins were purified using ion-exchange chromatography (DE-52) and sequential fractionation on Amicon ultrafiltration membranes. The effect of each protein fraction on the modulation of cytotoxic activity of NK cells, as effectors, against K562, as target cells, was assayed by enzymatic lactate dehydrogenase test. RESULTS: The most immunostimulatory effect on the cytotoxic activity of NK cells was observed for AR10 fraction, containing proteins with molecular weight of about 14.5 kDa on the reducible discontinuous sodium dodecyl sulfate polyacrylamide gel electrophoresis. DISCUSSION: Among the examined shark cartilage derived proteins, the most immunostimulatory effects on the NK cells cytotoxicity was found for AR10 fraction with molecular weight of about 14 kDa. We propose-the direct interactions of shark cartilage derived proteins with NK cells surface receptors may lead to the enhancing in the cytotoxic activity of NK cells. CONCLUSION: Thus AR10 fraction, proteins of about 14.5 kDa, has a novel immunostimulatory effect on the NK cells activity in vitro and if confirmed by in vivo trials, it may lead to its future clinical applications as, immunotherapy of cancer, HIV, and augmentation of host immune system related immunodeficiency disorders.

Sclareol modulates the Treg intra-tumoral infiltrated cell and inhibits tumor growth in vivo.

A regulatory or suppressor T cell is functionally defined as a T cell that inhibits an immune response by influencing the activity of another cell type. On the other hand, Th1 cells express IFN-gamma and mediate cellular immunity. Sclareol exhibits growth inhibition and cytotoxic activity against a variety of human cancer cell lines. In the first set of experiments, Sclareol was isolated from the plant Salvia sclarea and our study assessed the immuno-therapeutic effectiveness of Sclareol by direct intra-tumoral injection. Secondly, several immunological parameters such as splenocytes proliferation, intra-tumor CD4+CD25+Foxp3+ Treg cells, IFN-gamma and IL-4 secretion and tumor size were assessed to evaluate the anti-tumoral immune response. By all means, the findings confirmed that the activity of Sclareol could reduce the tumor growth in vivo against breast cancer.

Immunoregulatory Effects of Somatic Extract of Toxocara canis on Airway Inflammations in Murine Model.

BACKGROUND: The immunomodulatory role of many parasites is well-documented. The current study designed to assess the immunoregulatory effects of the somatic extract (SE) of Toxocara canis on murine model of airway inflammations. METHODS: The experiment was performed in department of parasitology of Tarbiat Mo-dares University, Tehran, Iran from November 2018 to May 2019. Totally 30 female BALB/c mice divided into one control group and two experimental groups (10 mice in each group). The ovalbumin (OVA) group was sensitized with OVA in alum, while the SE group was administered with SE and OVA in alum intraperitoneally. The control group was injected with PBS in alum. Then, SE and OVA groups were intranasally challenged with OVA for three consecutive days and the control group encountered with PBS at the same time. One day after the last challenge, real-time PCR and histopathology survey were conducted on isolated lung tissues. RESULTS: The gene expression of IL-25, IL-33, TNF-α and TLR-4 in SE group was significantly lower than OVA group (P<0.05). The level of IL-10, TGF-ß and IFN-γ were considerably higher than the OVA group (P<0.05). The inflammation was reduced in SE group, as the total cell number of bronchoalveolar lavage fluid was less than OVA group. Based on the histopathology findings the inflammation was decreased in SE group compared to the OVA group. CONCLUSION: Although, an inhibitory effect of SE of T. canis on airway inflammations was detected, there is still a long way ahead regarding the indication of the precise mechanisms.

Preliminary In Vitro Effects of CD8+ T Lymphocyte Specific for the CD20 Alternative Splicing D393-CD20 Peptide Expressed on Burkitt Lymphoma Cells.

The effective discovery of clinically relevant tumor antigens holds a fundamental role for the development of new diagnostic tools and anticancer immunotherapies. D393-CD20 mRNA is absent from normal resting B cells but present in various malignant or transformed B cells. CD8+T lymphocytes play a central role in immunity to cancer. In this study, we want use from T CD8+ against D393-CD20 for effect in RAMOS cell line. After isolation and expanding of specific TCD8 + Lymphocyte against D393-CD20 antigen, for examining the effect of specialized T lymphocyte clone of D393-CD20 antigen on RAMOS cell line, we co-cultured them together, and the rate of apoptosis were examined by flow cytometry and cytotoxicity techniques by using MTT technique. We observed that specialized TCD8+ lymphocyte of D393-CD20 antigen can induce apoptosis in malignant B-lymphocytes, and this antigen can be a proper target for immunotherapy.

Immunogenicity of a novel tetravalent dengue envelope protein domain III-based antigen in mice.

Dengue virus is a mosquito-borne pathogen that causes dengue diseases. All four serotypes of dengue virus are infectious for humans. Therefore, an efficacious dengue vaccine should be tetravalent to provide protection against all types of virus. The goal of this study was to design a new tetravalent recombinant protein from envelope protein of dengue viruses to induce virus-neutralizing antibodies against all four serotypes in mice. A chimeric protein was designed from domain III of envelope protein of all serotypes of dengue virus. Four domain III fragments were linked together by alpha helix making linkers. The final sequence of the designed protein was analyzed in silico and the coding gene sequence was deduced by reverse translation. After cloning and expression of the recombinant protein (ED3-tetravalent protein), identity of the purified protein was confirmed using a pan-dengue specific monoclonal antibody in Western blotting. Then, the immunogenicity of the purified protein was studied in mice using antibody titration. The efficacy of induced antibodies in neutralization of the virus was studies by FRNT method. Furthermore, the induction of cellular immunity was studied by measurement of cytokines using ELISA method and measurement of lymphocyte proliferation using MTT assay. The ED3-tetravalent protein was able to enhance neutralizing immunogenic response against all four dengue serotypes; in similar way to that of tetravalent formulation of four individual domain III-based polypeptides. It is suggested that the ED3-tetravalent fusion protein can induce broadly neutralizing antibody responses against all four serotypes of dengue virus in mice.

Evaluation of anti-tumor effects of tumor cell lysate enriched by HSP-70 against fibrosarcoma tumor in BALB/c mice.

The cytosolic members of the heat shock protein 70 (HSP-70) family have been shown to elicit protective cell mediated immunity in animal tumor models. The aim of this study was to investigate the effect of the HSP-70 enriched lysate of heated tumor cells as vaccines in cancer immunotherapy in the mouse model for WEHI-164 fibrosarcoma. Three animal bearing tumor groups were investigated: test group; vaccinated with enriched HSP-70 tumor lysate, control group I; vaccinated with tumor lysate only and control group II; received PBS. The results indicated that vaccinated mice in the test group had resulted in a significant reduction in tumor size and longer survival. To find the mechanism of these results, we measured the splenocytes proliferation, tumor infiltrated lymphocytes and cytotoxic activity of the splenocytes. The results indicated a significant increase in the proliferation of mouse splenocytes, a significant increase in the CD8+ lymphocytes as well as significant increase in the cytotoxic activity of splenocytes against the target cells in the test group. In addition, we analyzed the shifting of Th1/Th2 in all the groups. The results indicated a significant increase in the IFN-gamma production in the test group. These findings provided a useful therapeutic model for development of approaches to cancer treatments.

Determination of human papillomavirus type 16 genotype and construction of cloning vector pTZ57R encoding HPV16 E7 gene.

OBJECTIVE: To isolate and construct a cloning vector containing the human papillomavirus (HPV)16-E7 gene as a target for application as a DNA vaccine. METHODS: The study was performed in 2005 in Iran. The E7 gene, one of the most important HPV oncoproteins and a target molecule for therapeutic vaccines, was amplified by polymerase chain reaction (PCR). The PCR product was cloned into a suitable cloning vector and confirmed by colony-PCR, restriction enzyme analysis, and sequenced. RESULTS: The desired plasmid was sequenced and indicated 99% homology with those mentioned in the Genbank. CONCLUSION: The Iranian HPV16 E7 gene sequence is very similar to other sequences in the Genbank, and it can be used as a candidate gene in a therapeutic vaccine for Iranian patients with cervical cancer.

Enhancement of peritoneal macrophage phagocytic activity against Leishmania major by garlic (Allium sativum) treatment.

It has been shown that garlic (Allium sativum) extract modulates immune responses. Macrophage activation is required to establish control of the intracellular infection and progressive disease of leishmaniasis. In this study, we consider the effect of a garlic extract and a fraction isolated from it on the engulfment and destruction of Leishmania major by resident peritoneal macrophages of Balb/c mice. In regard to this study, the infiltration of macrophages in the peritoneal cavity after garlic treatment and the rate of amastigotes per macrophage were determined. The results show that a single dose of 20 mg/kg garlic extract intraperitoneally (i.p.) alters the number of peritoneal macrophages for at least 2 weeks. Intraperitoneal injection of garlic extract (20 mg/kg) or its protein fraction (0.04 mg/kg) augments parasite engulfment and destruction of intracellular amastigotes by macrophages.