Leishmaniasis is a worldwide disease prevalent in many tropical and sub tropical countries. Treatment of Leishmaniasis by chemotherapy is not wholly effective and is usually accompanied by unpleasant side effects. The development of an effective and inexpensive vaccine represents a practical way to control the disease, however at present no safe and effective vaccine is available. In the first part of the present study, the immunity induced by four different L. mexicana potential vaccines, including killed leishmania vaccine, Soluble L. mexicana Antigen (SLA), L. mexicana gp63 cDNA and CT26 tumour cells transfected with L. mexicana gp63, were compared. It was shown that DNA immunisation using L. mexicana gp63 generated the highest immunity to the parasite among the four tested vaccines where the killed leishmania vaccine and L. mexicana gp63 transfected CT26 tumour cells did not generate significant immunity. The efficacy of DNA immunisation by intramuscular injection or using gene gun, in generating immunity to leishmania was compared. Gene gun immunisation induced more immunity to the parasite and high levels of Th1 immune response, which were detected, one week after immunisation through determination of the IgG2a levels in blood serum. Gene gun immunisation also induced long-lasting CTL activity, which was detectable before and during the course of infection for up to 6 months. Immunogenicity of MHC class I restricted peptides derived from L. mexicana gp63 have been investigated. Using 'SYFPEITHI' software, four peptides with high affinity to human HLA-A2 and four peptides with high affinity to mouse H2-Ld were predicted, synthesized and tested in HHD II and BALB/c mice respectively. Only three of the peptides predicted with high affinity to HLA-A2 were immunogenic but only two of them were likely to be naturally processed, however, none were protective in HHD II mice against leishmania infection. Purification and application of OX40L, a ligand for T-cell co-stimulatory receptor, was investigated in L. mexicana BALB/c model. In addition to purification by protein A sepharose, the murine OX40L-IgG fusion protein produced by B9B8E2 cells (cells transfected with OX40L and IgG) was successfully purified by two novel resins, MBI & MEP. The biological activity of the OX40L-IgG purified by MBI resin was significantly higher than that of MEP or protein A sepharose resins. Application of OX40L-IgG resulted in healing of leishmania lesions or delaying in development of the lesions in leishmania-infected mice.

Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: Adam G. Marsh, College of Marine and Earth Studies. Includes bibliographical references.

To develop robust and reproducible methods for molecular typing of <I>Toxoplasma </I>strains, the DNA regions of 5<I>S</I> rDNA, 28S-18S rDNA <I>IGS SAG2</I>, and <I>GRA6</I> loci were examined. The 5<I>S</I> sequences were identical among 24 different strains; sequencing of the <I>IGS</I> region showed a few polymorphisms (0.66%) distinguishing virulence types. The IGS PCR-RFLP methods were developed and used to examine 29 strains of different virulence types. Sequence analysis of the IGS 5'-end showed great diversity between <I>Neospora caninum </I>and <I>T. gondii. </I>The IGS-RFLPs also clearly distinguished between those two closely related species. Nucleotide sequencing of the <I>SAG2</I> locus (a surface antigen coding gene) showed 1.37% polymorphisms among 24 strains. Apart from a single nucleotide change at the 5'-flanking region, the type III and type I strains were identical. However, three new alleles of this locus were identified in minor variants of the strains. Analysis of the coding region of the <I>GRA6</I> locus (a dense granule antigen coding gene) revealed a great degree of polymorphisms (3.24%) among 33 strains. Nine different alleles, representing the three current types and the minor variants of strains were characterised at this locus. A PCR-RFLP based on <I>GRA6</I> polymorphisms was developed which could distinguish the three major types of <I>T. gondii</I>. This marker proved to be a suitable tool for a population study of the <I>Toxoplasma </I>parasite. The predominance of non-synonymous nucleotide substitutions in <I>SAG2</I> and <I>GRA6</I> genes confirmed positive selection in these loci, suggesting they play an important role in the parasite virulence. Phylogenetic analysis based on the multi-locus sequence alignment showed the existence of more than three lineages in <I>Toxoplasma </I>populations.

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Diss. (sammanfattning) Stockholm : Karolinska institutet, 2001. / Härtill 6 uppsatser.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1954. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves [67]-[72]).

No description available.

Thesis (Ph. D.)--Medical College of Ohio, 2003. / "In partial fulfillment of the requirements for the degree of Doctor of Philosophy in Medical Sciences." Major advisor: Ronald Mellgren. Includes abstract. Document formatted into pages: iv, 126 p. Title from title page of PDF document. Includes bibliographical references (p. 92-124).

Techniques for the large-scale isolation of Cryptosporidium oocysts and sporozoites, obtained from the feces of experimentally infected Holstein calves, were developed employing discontinuous sucrose gradients and isopycnic Percoll gradients. The three step oocyst recovery method utilized two sequential discontinuous sucrose gradients followed by one Percoll gradient. Recovered oocysts were essentially free of debris and bacteria and represented 34% of the original oocyst suspension. Sporozoites were recovered from excystation mixtures on a single Percoll gradient. Sixty-three percent of the original sporozoites were recovered with 2.2% contamination by intact oocysts and virtually no oocyst walls. Eight anti-oocyst hybridomas were derived from oocyst-immunized mice: five from BALB/c mice and three from RBF/Dn mice. The monoclonal antibody (Mab) OW3 reacted specifically with C. parvum oocysts in immunofluorescent assays (IFA) and was shown to be superior to conventional stains for detecting oocysts in fecal smears from infected individuals. Sixteen anti-sporozoite hybridomas were derived from sporozoite-immunized BALB/c mice. The Mabs appeared to react with cell surface and cytoplasmic antigens by IFA. Two anti-sporozoite Mabs (C8C5, C6B6) reacted with a 20 kDa sporozoite antigen in western blots while the Mab C4A1 reacted with multiple antigens in western blots. These three Mabs (C8C5, C6B6, C4A1) were examined for potential modulation of cryptosporidial infections in vivo by oral Mab administration to oocyst-inoculated neonatal mice. The role for colostrum and breast milk in controlling cryptosporidial infections was examined by immunizing mouse dams and experimentally infecting their neonatal offspring. Colostrum and Mab-treated neonatal mice were sacrificed four days post infection. No difference in infection rates was observed among the treatment groups. Suckling mice treated daily with orally administered mixtures of Mabs (purified or ascitic fluid) showed significantly reduced parasite loads compared to control mice at four days post infection. In vitro cultivation of C. parvum was successful through asexual stages in human fetal lung, bovine turbinate and murine L929 cells. Parasite numbers that developed in the cell cultures varied from infection run to infection run.