Anaplasma marginale inactivated vaccine: dose titration against a homologous challenge

• Published in: Comparative immunology, microbiology and infectious diseases microbiology and infectious diseases, 2000-10, Vol.23 (4), p.239-252
• Main Authors: Rodrı́guez, S.D, Garcı́a Ortiz, M.A, Hernández Salgado, G, Santos Cerda, N.A, Aboytes Torres, R, Cantó Alarcón, G.J
• Format: Article
• Language: English
• Subjects: Adjuvants, Immunologic - administration & dosage; Anaplasma - immunology; Anaplasma - pathogenicity; Anaplasma marginale; Anaplasmosis - blood; Anaplasmosis - immunology; Anaplasmosis - prevention & control; Animals; Antibodies, Bacterial - blood; Bacterial Vaccines - administration & dosage; Bacterial Vaccines - immunology; Bacterial Vaccines - standards; Bacteriology; Biological and medical sciences; Body Temperature; Body Weight; Bovines; Bovins; Cattle; Cattle Diseases - immunology; Cattle Diseases - prevention & control; Dose-titration; Enzyme-Linked Immunosorbent Assay - veterinary; Female; Fundamental and applied biological sciences. Psychology; Hematocrit - veterinary; Homologous challenge; Homologue confrontation; Inactivated vaccine; Inactivé vaccin; Initial bodies; Initiaux corps; Mexico; Microbiology; Random Allocation; Vaccination - veterinary; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies; Vaccines, Inactivated - administration & dosage; Vaccines, Inactivated - immunology; Vaccines, Inactivated - standards
• ISSN: 0147-9571; 1878-1667
• DOI: 10.1016/S0147-9571(99)00076-4

The present study was performed to dose-titrate an Anaplasma marginale experimental immunogen derived from partially purified initial bodies from three geographically different Mexican strains. Three five-bovine groups were inoculated twice on days zero and 21 with A. marginale initial bodies equivalent to 1.5×10 10 (group I), 3×10 10 (group II) or 6×10 10 (group III) infected erythrocytes mixed with STDCM® adjuvant. A similar group served as non-vaccinated controls. All four groups were challenged with 1×10 8 infected erythrocytes from a donor cow with an increasing rickettsemia of strain MEX-15 on day 87 post-vaccination. The prepatent period was very similar for all four groups. All five non-vaccinated controls presented typical acute anaplasmosis syndrome reaching a mean of 30.9% rickettsemia and a loss of 73.4% in the packed cell volume (PCV). Two of five controls died of acute anaplasmosis. Within the vaccinated groups only one animal (group II) suffered acute disease and died. Although all the other vaccinated animals were free of clinical signs, they developed very low rickettsemias (3.2, 3.8 and 4.3%) and PCV losses of 49.9, 47.8, and 49.3% for groups I, II and III. The starting mean weight was very similar for all four groups. All animals lost weight following challenge but losses for groups I and II were lower and significantly different from group IV losses ( P⩽0.1). Although there were no significant differences among vaccinated groups, group III was more severely affected. Taken altogether, these results show a 93.3% protection against both illness and death for all groups; and 100% protection for groups I and III, and 80% for group II. Le but de l’étude était de définir la meilleure dose d’un immunogen expérimental contre l’Anaplasmose bovine. L’immunogen était dérivé des corps initiaux de trois isolats mexicains géographiquement différents. Trois groupes de cinq bovins ont été inoculés deux fois, les jours zéro et vingt et un, avec des corps initiaux équivalents à 1.5×10 10 (groupe I), 3×10 10 (groupe II) et 6×10 10 (groupe III) érythrocytes infectés et mélangés avec l’adjuvant STDCM®. Un groupe semblable de cinq bovins a servi de témoin non vaccinés. Le jour quatre-vingt-sept, les quatre groupes ont été éprouvés avec une dose de 1×10 8 érythrocytes infectés à l’aide de la souche MEX-15-099-01 d’ A. marginale. La période avant l’épreuve était très semblable pour chacun des quatre groupes. Les cinq bovins témoins ont présentés un syndrôme ai