Qualitative assessment of the humoral immune status against FMDV in post-vaccination cattle

Analyses on diluted sera would not measure the complete activity of the nat ural in-vivo serum environment used by humoral immune responses. Since thes e humoral defences must react rapidly, serum reactions occurring during 10 and 60 s were analysed. Primo- and multiple-vaccinated, efficiently respons ive, and protected animals were differentiated. A variation in the response s, particularly the quality of response, of individual animals was also now discernible. The critical importance of antibody-antigen contact time was demonstrated, wherein natural immunoglobulins and non-immunoglobulin opsoni ns would influence specific antibody reactivity, through an increased avidi ty of reaction with antigen. Although not measured directly, the influence of the non-specific serum components would be manifest through increased sp ecific antibody binding. By considering serum as an entity, analysis of all constituent components permits increased qualitative assessment of post-va ccination sera. (C) 2001 Elsevier Science Ltd. All rights reserved.