Africa / AHH / Animal Diseases / Cattle / East Africa / ECF / ILRI / LIVESTOCK-FISH / Vaccines

A roadblock to the development of a schizont-based vaccine for East Coast fever?

Antigen screening studies indicate that CD8 T cells from immune cattle recognise a large number of T. parva proteins, but whether or not CD8 T cells specific these proteins are all equally capable of mediating protection is not known. The lack of an antigen delivery system known to be capable of inducing protective CD8 T cell responses represents an obstacle to answering this important question. Continue reading

Africa / AHH / Animal Diseases / Cattle / East Africa / ECF / ILRI / LIVESTOCK-FISH / Vaccines

Nano attacks on the sporozoite to control East Coast fever

One of our strategies in the ECF Consortium is to target this stage of the sporozoite by improving the immune responses to the sporozoite antigen p67, which has shown to confer protection in previous experiments. We are about to test several nano-technologies for their ability to induce superior antibody responses, which can inhibit the infectivity of the sporozoite and eventually prevent disease. Continue reading

Africa / AHH / Animal Diseases / Cattle / East Africa / ECF / ILRI / LIVESTOCK-FISH / Vaccines

Immunogenicity and protection of the Theileria parva CTL antigen Tp1 using HAd5/MVA prime-boost vaccination

East Coast fever (ECF) is a lymphoproliferative disease caused by the protozoan parasite Theileria parva. It kills about one million cattle annually in Africa. Four groups of 5 BoLA-typed animals were immunized with the T. parva Tp1 antigen with or without leader sequence in the HAd5 viral vector and boosted with the same antigens in the MVA vector. Most animals generated CTL to the known epitope measured using tetramer staining, ELISpot and Cr-51-release assay. The CTL expressed perforin and lysed peptide pulsed PBMC. CD4 cells were shown to proliferate to the antigen. Challenge of the animals resulted in about 30% protection. Continue reading

Africa / AHH / Animal Diseases / Cattle / East Africa / ECF / ILRI / LIVESTOCK-FISH / Vaccines

Discovery of novel CTL epitopes by peptide library screening of CTL lines from Theileria parva immune animals

The parasite Theileria parva claims the life of approximately 1 million cattle every year. Immune animals to the parasite develop a lifelong immunity based on a cytotoxic T lymphocyte (CTL) response with a strong immunodominance restricted by the bovine leukocyte antigen (BoLA) class I molecules. In our goal of developing a next-generation vaccine against T. parva, we have undertaken to identify new CTL inducing antigens that can be included in a recombinant vaccine. A peptide library of 18-mer peptides overlapping by 12 amino acids and covering 500 genes of the whole parasite genome was synthesized; giving approximately 40,000 peptides aliquoted in pools of 50 peptides. Continue reading

Africa / AHH / Animal Diseases / Cattle / East Africa / ECF / ILRI / LIVESTOCK-FISH / Vaccines

Proteomics of Theileria parva sporozoites

East Coast fever (ECF) is a lymphoproliferative disease caused by the protozoan parasite Theileria parva. It kills about one million cattle annually in Africa. The sporozoite stage of this parasite, harbored in the salivary glands of the tick Rhipicephalus appendiculatus, invades and establishes infection in the bovine lymphocytes during tick feeding. However, little is known about the parasite molecules involved in this infection process. It is therefore necessary to elucidate the protein composition of the sporozoites to identify novel targets for blocking invasion. Blocking this initial stage of invasion presents a promising vaccine strategy for the control of ECF. Continue reading