Effect of anti-thymocyte serum on acquisition of resistance to infestation by Rhipicephalus appendiculatus larvae in rabbits

Administration of specific goat anti-thymocyte serum (ATS) to rabbits, prior to a primary infestation by Rhipicephalus appendiculatus larvae, blocked the acquisition of resistance significantly only in the third infestation. The larvae which fed on these rabbits had higher engorgement masses than did those feeding on untreated control rabbits. Also, a higher percentage (92%) of larval ticks fed on these animals than on the controls (88%). ATS also induced a leucopenia due to a lymphopenia in the treated rabbits. It was concluded that a T-cell-dependent component might be involved in acquired resistance to infestation by R. appendiculatus.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

Effect of cyclophosphamide on the acquisition of resistance to infestation by Rhipicephalus appendiculatus in rabbits

Parenteral administration of cyclophosphamide in rabbits made resistant to infestation by the tick Rhipicephalus appendiculatus, resulted in abrogation of the resistance phenomenon. As a result, a high percentage (83%) of the larval ticks fed to repletion. This was in contrast to the control rabbits which were expressing the phenomenon of resistance to infestation by the ticks. In the latter, only 28% of the ticks fed to repletion. Cyclophosphamide administration in rabbits induced a leucopenia and depressed antibody response to the heterologous antigen, sheep red-blood cells.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

Is the anemia in bovine trypanosomiasis caused by immunologic mechanisms?

Meeting: Conference on Recent Advances in the Knowledge of Pathogenicity of Trypanosomes, 20-23 Nov. 1978, Nairobi, KEIn IDL-329

Biological properties of bovine immunoglobulins and systemic antibody responses

The classification of bovine immunoglobulins is similar to that of nonruminant mammals, namely IgM, IgA, IgG1, IgG2 and IgE. There are minimal differences between IgG1 and IgG2 in complement fixation, ability to mediate passive cutaneous anaphylaxis, phagocytosis of coated erythrocytes by cultured monocytes and precipitation of antigens bearing unique determinants, such as ovalbumin. The functional properties of bovine IgM are identical to those of the IgM of other mammals. The antigens used in elucidating these properties, however, were of noninfective origin. These studies were extended to infectious agents such as African trypanosomes and Theileria parva. Cattle infected with Trypanosoma congelense and T. brucei produced high levels of specific IgM and IgG antibodies that could inhibit infectivity and mediate phagocytosis of homologous trypanosomes. The IgM produced in T. brucei infections differed from that produced against noninfectious agents in that it induced adherence of sensitized trypanosomes to, and phagocytosis by, cultured bovine monocytes in the absence of heterologous complement. The ability of trypanosome-infected cattle to respond to superinfection was depressed depending on the time interval between the first and the second inoculations. Cattle vaccinated with Brucella abortus vaccine during acute or chronic infection with T. congelense or T. vivax also showed reduced responses to the vaccine. The nature of these altered responses was reminiscent of antigenic competition. Cattle responded to T. parva infections by producing antibodies to the three stages of the parasite, namely sporozoites, macroschizonts and piroplams. Only the anti-sporozoite antibodies could block entry of sporozoite antibodies could block entry of sporozoites into target cells

Epidemiology and control of bovine malignant catarrhal fever

In IDL-535

Immunosuppression of humoral immune response in bovine trypanosomiasis

Meeting: Conference on Recent Advances in the Knowledge of Pathogenicity of Trypanosomes, 20-23 Nov. 1978, Nairobi, KEIn IDL-329