Induction of partial protection against Leishmania major in BALB/c mice by Leishmania tropica”

Leishmaniasis is a parasitic disease of man and other mammals. Immunity against leishmaniasis appears  to remain essentially species specific; however some cross-reactivity has been reported. The aim of this  study was analyzing cross-protection induced by Leishmania tropica (L. tropica) against Leishmania  major (L. major). BALB/c mice were infected with L. tropica in the footpad followed by a challenge infection  in the contra lateral footpad by L. tropica or L. major. Footpad thickness and parasite load in the footpad,  popliteal lymph node, and spleen were determined after challenge. The results demonstrate that L.  tropica induces partial protection of BALB/c mice against L. tropica as well as L. major. The  protection was more efficient against a homologous strain (L. tropica) than against a heterologous strain  (L. major). The partial protection against L. major was detected in the footpad tissues as well as popliteal  lymph node. No protection was observed against L. major in the spleen tissue. These findings have  implications in vaccination strategies for Leishmaniasis based on the use of heterologous species of the  parasite.

The Problem of Mixing up of Leishmania Isolates in the Laboratory: Suggestion of ITS1 Gene Sequencing for Verification of Species

Background: Leishmaniasis is endemic in Iran. Different species of Leishmania (L.) parasites are causative agents of this disease. Correct identification of Leishmania species is important for clinical studies,prevention, and control of the diseases. Mix up of Leishmania isolates is possible in the laboratory, so there is need for verification of species for isolates of uncertain identity. Different methods may be used for this purpose including isoenzyme electrophoresis and molecular methods. The isoenzyme lectrophoresis, due to its drawbacks, is feasible only in specialized laboratories while molecular methods may be more feasible. The aim of this research was to study the application of the internal transcribedspacer 1 (ITS1) sequencing method, in comparison to isoenzyme electrophoresis method, for verification of Leishmania species.Methods: Six Leishmania isolates were received from different research institutions in Iran. The species of these isolates were known by donating institution according to their isoenzyme profile. The species of these isolates were re-identified in Pasteur Institute of Iran by PCR amplification of ITS1 followed bysequencing and comparison of these sequences with Leishmania sequences in GenBank. Isoenzyme electrophoresis was performed for confirmation of the results of ITS1.Results: ITS1 sequence showed that some isolates were mixed up or contaminated with Crithidia. Isoenzyme electrophoresis confirmed the results of ITS1 sequences.Conclusion: ITS1 sequencing is relatively more feasible than the traditional isoenzyme electrophoresismethod and is suggested for verification of Leishmania species

Genetic susceptibility in tuberculosis

The importance of host genetic factors in determining susceptibility to tuberculosis (TB) has been studied extensively using various methods, such as casecontrol, candidate gene and genome-wide linkage studies. Several important candidate genes like human leucocyte antigen/alleles and non-human leucocyte antigen genes, such as cytokines and their receptors, chemokines and their receptors, pattern recognition receptors (including toll-like receptors, mannose binding lectin and the dendritic cell-specific intercellular adhesion molecule-3 grabbing nonintegrin), solute carrier family 11A member 1 (formerly knownas natural resistance-associated macrophage protein 1) and purinergic P2X7 receptor gene polymorphisms, have been associated with differential susceptibility to TB in various ethnic populations. This heterogeneity has been explained by host–pathogen and gene– environment interactions and evolutionary selection pressures. Although the achievements of genetics studies might not yet have advanced the prevention and treatment of TB, researchers have begun to widen their scope of investigation to encompass these practical considerations

Effect of Giardia lamblia Infection on the Cognitive Function of School children

Background: The association between helminthic parasitic infection and cognitive function has long been recognized, however there are few reports about Giardia lamblia infection. This paper describes a study about the effect of G. lamblia infection on the cognitive function. Methods: One hundred thirty two children infected with G. lamblia from Robat Karim south of western Tehran, Iran were compared with 150 children without any parasitic infection. These two groups were identical in socioeconomic and nutritional status. Cognitive function was assessed using, three tests from Wechsler Intelligence Scale for children and one subset of the Clinical Evolution of Language Function. Results: Comparison of two groups revealed that uninfected children improved significantly more than children who had G. lamblia infection in the tests of Fluency (P< 0.02) and Digit-span Forwards/ Backwards (P< 0.004). Conclusion: Regular stool examination is suggested in areas with low hygienic conditions, since G. lamblia infection might be present without any clinical manifestation

Complete conservation of an immunogenic gene (lcr1) in Leishmania infantum and Leishmania chagasi isolated from Iran, Spain and Brazi

Background & objectives: Kala-azar is the visceral and most severe form of leishmaniasis thatleads to death if untreated. The causative agents of visceral leishmaniasis (VL) are members ofLeishmania (L.) donovani complex which includes L. chagasi and L. infantum. Genome sequenceshave raised the question whether L. chagasi and L. infantum are synonymous or different. Thisquestion has important implications for clinical and epidemiological studies, evaluation of vaccinesand drugs, and disease control. LCR1 is an immunogenic molecule discovered from L. chagasiwith potential as a component of a Leishmania subunit vaccine. If this protein has potentials forbeing used in a vaccine or diagnostic testing, there should be little variability in this moleculebetween L. infantum isolates from diverse geographic regions. The aim of this study was to determinewhether lcr1 of an Iranian strain of L. infantum was identical to lcr1 of both L. infantum strainfrom a different geographic region (Spain) and that of an L. chagasi isolate from Brazil.Methods: L. infantum isolated from an Iranian kala-azar patient was studied. Lcr1 from this isolatewas PCR amplified, cloned, and studied by restriction digest analysis and sequencing.Results: The sequences of lcr1 of the Iranian L. infantum were completely identical at nucleotidelevel to lcr1 sequences of both the Spanish L. infantum and the Brazilian L. chagasi strains.Conclusion: Complete conservation of the DNA sequence encoding for LCR1 molecule betweengeographically distinct Leishmania species adds credibility to the potential for LCR1 as a componentof a subunit vaccine and diagnostic test for kala-azar