Van der Walt, Etienne2019-03-262019-03-261998https://hdl.handle.net/10539/26634A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science.This is the first report comparing the inducible humoral immune responses of' two long-lived arthropods. Inducible humoral immune responses were detected in two arthropods namely, the scorpion Opisthopthalmus latitnanus (Arachnida) and the millipede Triaetiostreptus triodus (Diploooda: Spirostreptidae). These anti-bacterial activities were elicited by "ve gram-negative and gram-positive bacteria. A dramatic hemocytopenia was demonstrated in both the millipede and scorpion after experimental infection, suggesting the possible release of a hemocyte depletion factor. The anti-bacterial humoral responses of the millipede and the scorpion were similar in magnitude to those that have been reported for a large variety of short-lived insects. I also provide further characterisation of the anti-bacterial defence proteirus) of the Kalana n millipede. My results suggest that the humoral immune response of arthopods may have a long and conserved phylogeny.enArthropoda.Immune response.Scorpions.Millipedes.Thesis