A quantitative assessment of primary and secondary immune responses in cattle using a B cell ELISPOT assayEric A. Lefevre, B. Veronica Carr, Helen Prentice and Bryan Charleston
Compton Laboratory, Institute for Animal Health, High Street, Compton, Newbury, Berkshire RG20 7NN, United Kingdom
Received 20 March 2008; accepted 29 September 2008; published online 3 October 2008
Abstract - The aim of the study was to build a comprehensive picture of the appearance in the blood stream of Ag-specific plasma cells and memory B cells in the bovine model. For this purpose, we have developed a method allowing the detection and quantification of both cell types within individual calves immunised with ovalbumin. During the primary response, we detected a burst of ovalbumin-specific plasma cells at days 6 and 7 post-immunisation, which was followed by the production of specific Ab, whereas a gradual increase of memory B cells was only detected from day 15. As expected, a boost immunisation performed 7 weeks later induced a quicker and stronger secondary response. Indeed, a burst of plasma cells was detected in the blood at days 3 and 4, which was followed by a strong increase in Ab titres. Furthermore, a burst of memory B cells, and not a gradual increase, was detected at days 5 and 6 post-boost immunisation. Importantly, we showed a strong correlation between the anti-ovalbumin-specific IgG titres detected 5 months after secondary immunisation and the plasma cell numbers detected in the blood at the peak response after secondary immunisation. The detection and quantification of plasma cells following an mmunisation/vaccination strategy could constitute a very effective means for predicting the magnitude and longevity of an Ab response.
Key words: bovine immunology / memory B cells / plasma cells / humoral response / vaccines
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© INRA, EDP Sciences 2008