Cancer is a disease that is caused by mutations in somatic cells. Metastasis is the major cause of death from cancer and often complicates treatment. Malignant tumours secrete degradative enzymes such as cathepsin L which degrade the extracellular matrix to facilitate tumour invasion and metastasis. The immune system does not normally recognize and eradicate tumours because they arise from self tissues to which the immune system is tolerant. Self antigens are poorly immunogenic because they lack T cell help. In this study, a foreign glucosidase was conjugated to self rabbit cathepsin L using glutaraldehyde to specifically provide T helper cell epitopes. The conjugate was used to immunise two male rabbits. A second pair of rabbits (male and female), was primed with sheep cathepsin L (to induce T helper cell activation) and received rabbit cathepsin L boosters. A third pair of rabbits which served as a control was immunised with sheep cathepsin L. The two pairs of test rabbits made high avidity antibodies against rabbit cathepsin L, showing a similar response to control rabbits when antibodies were tested in an ELISA. Western blot analysis showed that these anti-cathepsin L autoantibodies were specific for rabbit cathepsin L. Rabbits which were immunised with the conjugate were · inoculated with sheep cathepsin L nine weeks after the final inoculation with the conjugate. Analysis of antibodies in an ELISA showed that antibody responses against rabbit cathepsin L were augmented in a manner that is characteristic of memory responses. Low titre antibodies against sheep cathepsin L were also produced. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Overexpression of IL-12 and IL-23 has been implicated in the pathogenesis of Crohn’s disease. Targeting these cytokines with monoclonal antibodies has emerged as an effective therapy, but one with adverse reactions. In this study, we sought to develop peptide-based virus-like particle vaccines specific to p40 unit (shared by IL-12 and IL-23) or IL-12 (p35) or IL-23 (p19) and evaluate the effects of the vaccine in 2,4,6-trinitrobenzene sulphonic acid (TNBS)- and dextran sodium sulfate (DSS)-induced acute and chronic murine colitis. Three vaccines against p40 induced high-titered and long-lasting antibodies to IL-12, IL-23 and p40 without the use of adjuvants. Vaccine-induced antibodies could block IL-12- and IL-23-induced biological functions in vitro dose-dependently. One of the three p40 vaccines was selected for further evaluation in acute and chronic colitis. Administration of the vaccine before or after the commencement of TNBS or DSS delivery, significantly improved body weight loss and decreased inflammatory scores, collagen deposition, and the expression of p40, IL-12, IL-23, IL-17 and TNF in colon tissues, compared with mice receiving carrier protein (HBcAg) or saline. Moreover, in mesenteric lymph nodes, vaccinated mice exhibited a trend to lower percentages of Th1 cells in acute colitis and of Th17 cells in chronic colitis compared to carrier and saline controls. Vaccinated mice also had higher ratios of Treg/Th1 and Treg/Th17 and higher percentages of apoptosis in Th1 and Th17 cells than controls. Vaccine treatment decreased the infiltration of CD11c+ cells into the gut, but promoted the production of IL-10 from these cells. Safety evaluation indicated that vaccine immunization did not increase the susceptibility to the infection of chlamydia muridarum. Two vaccines specific to IL-12 (against p35) and one vaccine to IL-23 (against p19) were also developed. They induced specific antibodies against IL-12 and IL-23, respectively. IL-23p19 vaccine immunization, not IL-12p23 vaccine, ameliorated TNBS-induced chronic colitis. In summary, IL-12/IL-23p40 vaccine treatment ameliorated murine colitis through rebalancing Th1/Th17/Treg responses, promoting Th1 and Th17 apoptosis, and promoting IL-10 production, and did not increase the severity of chlamydia muridarum infection. This vaccine strategy may provide a novel long-term treatment for Crohn’s disease.

Overexpression of IL-12 and IL-23 has been implicated in the pathogenesis of Crohn’s disease. Targeting these cytokines with monoclonal antibodies has emerged as an effective therapy, but one with adverse reactions. In this study, we sought to develop peptide-based virus-like particle vaccines specific to p40 unit (shared by IL-12 and IL-23) or IL-12 (p35) or IL-23 (p19) and evaluate the effects of the vaccine in 2,4,6-trinitrobenzene sulphonic acid (TNBS)- and dextran sodium sulfate (DSS)-induced acute and chronic murine colitis. Three vaccines against p40 induced high-titered and long-lasting antibodies to IL-12, IL-23 and p40 without the use of adjuvants. Vaccine-induced antibodies could block IL-12- and IL-23-induced biological functions in vitro dose-dependently. One of the three p40 vaccines was selected for further evaluation in acute and chronic colitis. Administration of the vaccine before or after the commencement of TNBS or DSS delivery, significantly improved body weight loss and decreased inflammatory scores, collagen deposition, and the expression of p40, IL-12, IL-23, IL-17 and TNF in colon tissues, compared with mice receiving carrier protein (HBcAg) or saline. Moreover, in mesenteric lymph nodes, vaccinated mice exhibited a trend to lower percentages of Th1 cells in acute colitis and of Th17 cells in chronic colitis compared to carrier and saline controls. Vaccinated mice also had higher ratios of Treg/Th1 and Treg/Th17 and higher percentages of apoptosis in Th1 and Th17 cells than controls. Vaccine treatment decreased the infiltration of CD11c+ cells into the gut, but promoted the production of IL-10 from these cells. Safety evaluation indicated that vaccine immunization did not increase the susceptibility to the infection of chlamydia muridarum. Two vaccines specific to IL-12 (against p35) and one vaccine to IL-23 (against p19) were also developed. They induced specific antibodies against IL-12 and IL-23, respectively. IL-23p19 vaccine immunization, not IL-12p23 vaccine, ameliorated TNBS-induced chronic colitis. In summary, IL-12/IL-23p40 vaccine treatment ameliorated murine colitis through rebalancing Th1/Th17/Treg responses, promoting Th1 and Th17 apoptosis, and promoting IL-10 production, and did not increase the severity of chlamydia muridarum infection. This vaccine strategy may provide a novel long-term treatment for Crohn’s disease.

No description available.

Cancer vaccines can fail despite the induction of large numbers of CD8+ T cells. Two categories of memory CD8+ T cells have been defined; central memory (TCM, IL-7RαhighCD44highCD62Lhigh) and effector memory (TEM, IL-7RαhighCD44highCD62Llow). It is clear that the memory phenotype of CD8+ T cells can affect vaccine potential; however methods to augment a beneficial phenotype are not clear. I have compared three vaccine delivery systems: Listeria monocytogenes, Salmonella enterica serovar Typhimurium and the particulate liposomal adjuvant, archaeosomes, for their efficacy to protect against murine melanoma. My study revealed that the anti-tumour response is strongly influenced by the kinetics, phenotype, and lymph node homing potential of CD8+ T cells. Listeria monocytogenes-ovalbumin (LM-OVA) induced TCM cells were adept at long lasting protection against B16-OVA melanoma due to their increased homeostatic and antigen-induced proliferation, interleukin-2 production, and ability to extravasate into tumour draining lymph nodes. Conversely, although Salmonella Typhimurium-ovalbumin (ST-OVA) induced TEM, produced IFN-γ, and killed target cells, this was insufficient for long-term tumour protection. Selectin-ligand engagements of TCM cells influenced their homing potential and efficacy against murine melanoma. Fucosyltransferase deficient (FtDKO) mice, lacking functional selectin ligands, were vaccinated with LM-OVA; despite the activation of cytotoxic CD8+ T cells, there was a reduced protection against murine melanoma compared to wild-type. FtDKO CD8+ T cells exhibited reduced extravasation into FtDKO lymph nodes compared to wild-type. Additionally, fewer FtDKO CD8+ T cells compared to wild-type migrated into tumour sites. Archaeosome vaccination was used to compare the influence of CD8+ T cell quantity versus phenotype. Single or multiple therapeutic vaccinations with archaeosome-OVA yielded transient melanoma tumour protection, despite an increased frequency of circulating and tumour infiltrating CD8+ T cells. This correlated with increased expression of Program death receptor-1 (PD-1) on CD8+ T cells and induction of regulatory T cells. Prophylactic archaeosome-OVA vaccination resulted in a maximal frequency of antigen-specific CD8+ T cells of ~50-60 % with just three injections, and ~50 % of the mice were of mice were afforded long-term tumour protection (> 90 days). Overall, my study shows that the choice of vaccine adjuvant and/or vector can profoundly influence CD8+ T cell quality and cancer vaccine efficacy.

Thesis (Ph.D) -- McMaster University, 1997 / Includes bibliographical references Also available via World Wide Web.

Diss. (sammanfattning) Uppsala : Univ., 2002. / Härtill 6 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 6 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2004. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 4 uppsatser.