HOST FACTORS AFFECTING THE HOMOLOGOUS AND HETEROLOGOUS IMMUNE-RESPONSE OF CATTLE TO FMDV - GENETIC BACKGROUND, AGE, VIRUS-STRAINS AND ROUTEOF ADMINISTRATION

Sixty bulls were tested for antibodies to the heterologous serotype C- 1 of FMDV following repeatable vaccinations with a commercial trivalen t vaccine (O-1, A(22),, Asia1), Six (10%) bulls were found to possess rather high levels of heterologous neutralizing antibodies which showe d accumulative trend with age, Two high positive and two negative bull s for the heterologous serotype C, were selected for progeny rest invo lving ten daughters of each bull, The four bulls, either positive or n egative for the heterologous serotype C-1, showed significant phenotyp ic correlation between their heterologous and homologous titers (O-1, A(22), Asia1), This correlation between heterologous and homologous an tibody titers was not found in the daughters of these bulls. However; two, of ten daughters of one positive bull, to C-1 showed individual h igh titers (greater than or equal to 1.5), The intradermal (ID) as com pared to subcutaneous (SC) route of administration resulted in higher rate of responders to both heterologous serotypes C-1 and SATI, The he terologous immune response to FMDV in Israeli-Friesian cattle was foun d to be related to the age of the host, multiplicity of vaccinations, route of vaccination, kind and numbers of the antigens used in the vac cine, The homologous immune? response is also controlled by genetic fa ctors. (C) 1998 Elsevier Science Ltd. All rights reserved.